kcov: collect coverage from remote threads #1

xairy · 2018-06-11T14:39:55Z

No description provided.

dvyukov

First round. Need to see usage example to review further.

dvyukov · 2018-06-12T12:58:47Z

include/uapi/linux/kcov.h

@@ -32,4 +36,11 @@ enum {
 #define KCOV_CMP_SIZE(n)        ((n) << 1)
 #define KCOV_CMP_MASK           KCOV_CMP_SIZE(3)

+#define KCOV_REMOTE_HANDLE_USB  0x4242424200000000ul


Do we need whole 4 bytes for subsystem id? I would do 2 bytes for subsystem id, because we may need more space for subsystem-specific id.

s/ul/ull/ or drop it entirely

dvyukov · 2018-06-12T13:00:52Z

include/uapi/linux/kcov.h

+
+static inline u64 kcov_remote_handle_usb(int bus)
+{
+	return KCOV_REMOTE_HANDLE_USB + (u64)bus;


Is u64 correct type to use in uapi headers?

__u64, done.

dvyukov · 2018-06-12T13:01:46Z

include/uapi/linux/kcov.h

@@ -7,6 +7,10 @@
 #define KCOV_INIT_TRACE			_IOR('c', 1, unsigned long)
 #define KCOV_ENABLE			_IO('c', 100)
 #define KCOV_DISABLE			_IO('c', 101)
+#define KCOV_REMOTE_ENABLE		_IOW('c', 102, unsigned long)


add usage example/test to Documentation/dev-tools/kcov.rst

dvyukov · 2018-06-12T13:02:53Z

kernel/kcov.c

@@ -50,12 +51,60 @@ struct kcov {
 	enum kcov_mode		mode;
 	/* Size of arena (in long's for KCOV_MODE_TRACE). */
 	unsigned		size;
+


I don't understand grouping introduced by this newline.
size and area are separated, while it's size of the area

Typo, fixed.

dvyukov · 2018-06-12T13:03:05Z

kernel/kcov.c

 	/* Coverage buffer shared with user space. */
 	void			*area;
 	/* Task for which we collect coverage, or NULL. */
 	struct task_struct	*t;
+	/* Collecting coverage from remote threads. */
+	bool			remote;
+	/* Size of remote arena (in long's) */


dot at the end of sentence

dvyukov · 2018-06-12T13:04:52Z

kernel/kcov.c

 };

+DEFINE_SPINLOCK(kcov_remote_lock);
+DEFINE_HASHTABLE(kcov_remote_map, 4);
+struct list_head kcov_remote_areas = LIST_HEAD_INIT(kcov_remote_areas);


dvyukov · 2018-06-12T13:10:00Z

kernel/kcov.c

+	u64 handle;
+
+	if (cmd == KCOV_REMOTE_TRACK) {
+		if (copy_from_user(&handle, (void *)arg, sizeof(handle)))


get_user will be simpler here

dvyukov · 2018-06-12T13:12:14Z

kernel/kcov.c

-	if (WARN_ON(kcov->t != t)) {
-		spin_unlock(&kcov->lock);
-		return;
+	if (!kcov->remote) {


I think we just need to do WARN_ON(kcov->remote) here. Task exiting with remote kcov enabled is a kernel bug. Or not?

No, it's OK to have kcov->remote set, but it should only happen in the master thread (the one that created kcov device). Reworked this part anyway.

dvyukov · 2018-06-12T13:13:49Z

kernel/kcov.c

+	struct kcov_remote *remote;
+	struct hlist_node *tmp;
+
+	spin_lock(&kcov->lock);


Shouldn't all this code go into kcov_put?

You mean the code that frees areas? We could move it there. We won't need it here in this case, but we'll still need it in KCOV_REMOTE_DISABLE.

This code must to be there. close does not mean much, it merely drops a reference to kcov, kcov still can be alive after close. You must not do shutdown in close.

dvyukov · 2018-06-12T13:17:15Z

kernel/kcov.c

+		if (!kcov->remote)
+			return -EINVAL;
+		spin_lock(&kcov_remote_lock);
+		hash_for_each_safe(kcov_remote_map, bkt, tmp, remote, hnode) {


This code duplicates what we already have in kcov_close (or at least it should). We need a helper function that does all of this and which is called from both places, just like we have kcov_task_init for KCOV_DISABLE and task exit now.

xairy · 2018-06-12T16:33:42Z

@dvyukov PTAL

dvyukov · 2018-06-12T17:29:26Z

Documentation/dev-tools/kcov.rst

+	handle = kcov_remote_handle_usb(1);
+	if (ioctl(fd, KCOV_REMOTE_TRACK, &handle))
+		perror("ioctl"), exit(1);
+	__atomic_store_n(&cover[0], 0, __ATOMIC_RELAXED);


Why do we need this?

Can't mmap'ed area contain garbage? This would reset the coverage counter.

mmaped memory contains zeros.

You copy-pasted it from the previous test:

/* Reset coverage from the tail of the ioctl() call. */ __atomic_store_n(&cover[0], 0, __ATOMIC_RELAXED);

But this is not applicable here. We don't trace ioctl in this case.

Indeed, vmalloc_user() zeroes out the memory. Fixed.

It's not so about how we currently allocate memory. The mmap'ed memory must be zeros and we don't need this store. If the memory contains garbage, then we introduced a huge kernel infoleak and need to fix it elsewhere rather than workaround it here.

dvyukov · 2018-06-12T17:29:39Z

Documentation/dev-tools/kcov.rst

+	__atomic_store_n(&cover[0], 0, __ATOMIC_RELAXED);
+
+	/* Sleep. The user needs to trigger some activity on the USB bus #1. */
+	usleep(2000 * 1000);


dvyukov · 2018-06-12T17:31:34Z

kernel/kcov.c

+		}
+		remote = kmalloc(sizeof(*remote), GFP_ATOMIC);
+		if (!remote)
+			return -ENOMEM;


spin_unlock(&kcov_remote_lock) before return

dvyukov · 2018-06-12T17:32:08Z

kernel/kcov.c

+			return -EINVAL;
+		kcov->remote_size = size;
+	case KCOV_REMOTE_TRACK:
+		if (!kcov->remote || !kcov->remote_size)


How can kcov->remote_size be 0 if kcov->remote is set? Can it?

No, removed the check.

dvyukov · 2018-06-12T17:35:29Z

kernel/kcov.c

+
+	if (cmd == KCOV_REMOTE_TRACK) {
+		if (get_user(handle, (u64 *)arg))
+			return -EINVAL;


dvyukov · 2018-06-12T17:36:05Z

kernel/kcov.c

+		spin_lock(&kcov_remote_lock);
+		if (kcov_remote_find(handle)) {
+			spin_unlock(&kcov_remote_lock);
+			return -EINVAL;


I would return EEXIST to simplify debugging.

xairy · 2018-06-12T18:03:59Z

@dvyukov PTAL

dvyukov · 2018-06-13T08:04:01Z

Documentation/dev-tools/kcov.rst

+    #define KCOV_ENABLE                     _IO('c', 100)
+    #define KCOV_DISABLE                    _IO('c', 101)
+
+    #define KCOV_REMOTE_ENABLE		_IOW('c', 102, unsigned long)


Please also show how this will be used in syzkaller. I wonder if we need to combine KCOV_REMOTE_ENABLE, KCOV_REMOTE_SIZE and COV_REMOTE_TRACK into a single ioctl that accepts all necessary info to setup remote tracing rather than accept it all in small pieces.

Merged them all into KCOV_REMOTE_ENABLE.

dvyukov · 2018-06-13T08:07:36Z

kernel/kcov.c

+		spin_unlock(&kcov_remote_lock);
+		return;
+	}
+	area = kcov_remote_area_get();


If we grab an area from the global list, it is not necessary of remote->kcov->remote_size size...

dvyukov · 2018-06-13T08:11:45Z

kernel/kcov.c

 void kcov_task_exit(struct task_struct *t)
 {
 	struct kcov *kcov;

 	kcov = t->kcov;
 	if (kcov == NULL)
 		return;
+


Task must not exit inside of kcov_remote_start/stop region, right? If so, please add a WARN here.

Yes, the existing WARN_ON(kcov->t != t) covers this case, added a comment with explanations.

dvyukov · 2018-06-13T08:12:45Z

kernel/kcov.c

+	t->kcov = NULL;
+
+	spin_lock(&kcov->lock);
+	if (kcov->remote)


Is t possible that we are here, but kcov->remote is false? How?

Yes, when KCOV_DISABLE happened between kcov_remote_start() and kcov_remote_stop(). Added a comment.

dvyukov · 2018-06-13T08:18:30Z

kernel/kcov.c

+	if (!t->kcov)
+		return;
+
+	kcov = t->kcov;


Better to move this before the if above and then check (!kcov).

dvyukov · 2018-06-13T08:21:03Z

kernel/kcov.c

@@ -391,8 +486,59 @@ static int kcov_ioctl_locked(struct kcov *kcov, unsigned int cmd,
 		if (WARN_ON(kcov->t != t))
 			return -EINVAL;
 		kcov_task_init(t);
-		kcov->t = NULL;
-		kcov->mode = KCOV_MODE_INIT;
+		kcov_reset(kcov);


We need to check that !kcov->remote similarly to how we check kcov->remote in KCOV_REMOTE_DISABLE. But thinking of this, it's better to just use KCOV_DISABLE in both cases, we know if it's remote or not anyway, and both ioctls share most of the code.

Merged KCOV_REMOTE_DISABLE into KCOV_DISABLE.

dvyukov · 2018-06-13T08:27:01Z

kernel/kcov.c

+	/* Check that kcov_remote_start is not called twice. */
+	if (WARN_ON(t->kcov))
+		return;
+


I think we also need to check that we are in task context here. It won't work from interrupts, right?

Added a check.

dvyukov · 2018-06-13T08:33:43Z

kernel/kcov.c

+		if ((1 + dst[0] * KCOV_WORDS_PER_CMP) * sizeof(u64) >=
+				dst_area_size * sizeof(unsigned long))
+			return;
+		bytes_to_move = min(


Did it become simpler with memcpy? This version is quite hard to follow.
We need to use READ_ONCE/WRITE_ONCE at least for dst[0], dst is mapped to user-space. For that you will need to introduce some helper variables. Perhaps it will become easier to follow with appropriate helper variables, like "this is how much free space we have in dst", "this is how much we want to copy from src", etc.

xairy · 2018-06-13T19:29:45Z

@dvyukov PTAL

dvyukov · 2018-06-14T07:51:18Z

kernel/kcov.c

+	unsigned long remote_arg_size;
+
+	if (cmd == KCOV_REMOTE_ENABLE) {
+		remote_arg = (struct kcov_remote_arg *)arg;


This line seems excessive.

dvyukov · 2018-06-14T07:55:50Z

Documentation/dev-tools/kcov.rst

+	arg->trace_mode = KCOV_TRACE_PC;
+	arg->area_size = COVER_SIZE;
+	arg->num_handles = 1;
+	arg->unused = 0;


excessive since we do memset above

dvyukov · 2018-06-14T07:56:06Z

Documentation/dev-tools/kcov.rst

+	arg = malloc(sizeof(*arg) + sizeof(uint64_t));
+	if (!arg)
+		perror("malloc"), exit(1);
+	memset(arg, 0, sizeof(*arg) + sizeof(uint64_t));


perhaps use calloc to not duplicate size calculation

dvyukov · 2018-06-14T07:56:52Z

kernel/kcov.c

+		kcov->remote = true;
+		kcov->remote_size = remote_arg->area_size;
+		spin_lock(&kcov_remote_lock);
+		for (i = 0; i < remote_arg->num_handles; i++) {


FWIW this is TOCTOU bug ;)
this is not the value you used to allocate handles array

Oops, fixed =)

dvyukov · 2018-06-14T07:58:38Z

kernel/kcov.c

+			return -EINVAL;
+		remote_arg_size = sizeof(*remote_arg) +
+			remote_num_handles * sizeof(u64);
+		remote_arg = kmalloc(remote_arg_size, GFP_KERNEL);


will be simpler and shorter with memdup_user

dvyukov · 2018-06-14T08:19:25Z

kernel/kcov.c

+	spin_unlock(&kcov->lock);
+
+	spin_lock(&kcov_remote_lock);
+	kcov_remote_area_put(area, kcov->remote_size);


Strictly saying, kcov can be reinitialized with different remote_size between kcov_remote_start and kcov_remote_start. We better use area_size cached in current.

dvyukov · 2018-06-14T08:23:36Z

kernel/kcov.c

+	switch (mode) {
+	case KCOV_MODE_TRACE_PC:
+		WRITE_ONCE(*(unsigned long *)dst_area, dst_len + entries_moved);
+		*(unsigned long *)src_area = 0;


We reset first word both here and in kcov_remote_start. kcov_remote_start looks like a better place, because it happens right before we start tracing, so we are sure that we start with clear state. So I think we can remove reset here and in the next case.

dvyukov · 2018-06-14T08:24:14Z

kernel/kcov.c

+		WRITE_ONCE(*(u64 *)dst_area, dst_len + entries_moved);
+		*(u64 *)src_area = 0;
+		break;
+	default:


Without WARN empty default break is pointless. Either add WARN, or remove this. My vote is for removing.

GCC complains that we don't cover all possible values here if I remove default.

dvyukov · 2018-06-14T08:35:28Z

kernel/kcov.c

+	if (dst_len >= (INT_MAX - count_size) / entry_size)
+		return;
+	dst_occupied = count_size + dst_len * entry_size;
+	if (dst_occupied >= dst_area_size * word_size)


Can't we remove both if's with dst_len > (dst_area_size - count_size) / entry_size? It seems that this will put pretty strict limit on dst_len and prevent any overflows.

Yes, I think so. Done.

dvyukov · 2018-06-14T08:35:53Z

kernel/kcov.c

+		return;
+	}
+
+	dst_entries = dst_area + count_size + dst_len * entry_size;


This can be moved after we calculate dst_occupied and reuse dst_occupied value.

xairy · 2018-06-14T13:50:39Z

@dvyukov PTAL

dvyukov · 2018-06-15T07:42:32Z

kernel/kcov.c

+static void kcov_stop(struct task_struct *t)
+{
+	WRITE_ONCE(t->kcov_mode, KCOV_MODE_DISABLED);
+	barrier();


There are some kcov changes just merged upstream, in particular fix for kcov_stop. Don't forget to rebase this before mailing.

I will once the new rc1 is released.

dvyukov · 2018-06-15T07:45:18Z

kernel/kcov.c

 	spin_lock(&kcov->lock);
+	/*
+	 * If !kcov->remote, this checks that t->kcov == kcov->t.


t->kcov is of type struct kcov*
kcov->t is of type struct task_struct*
they are never equal

dvyukov · 2018-06-15T07:53:31Z

kernel/kcov.c

+		if (IS_ERR(remote_arg)) {
+			res = PTR_ERR(remote_arg);
+			if (res != -ENOMEM)
+				kfree(remote_arg);


I am not following. If res != -ENOMEM, it also allocated the memory block? How can it even return both error and a pointer?

It can't, my bad, fixed.

dvyukov · 2018-06-15T07:55:14Z

kernel/kcov.c

+				kfree(remote_arg);
+			return res;
+		}
+		if (remote_arg->num_handles != remote_num_handles) {


I would fold these 2 if's into remote_arg->num_handles != remote_num_handles || remote_arg->unused just to save few lines.

dvyukov · 2018-06-15T07:57:53Z

kernel/kcov.c

+	if (!area) {
+		area = vmalloc(size * sizeof(unsigned long));
+		if (!area)
+			return;


need kcov_put here

dvyukov · 2018-06-15T08:05:12Z

kernel/kcov.c

+	 * KCOV_DISABLE could have been called between kcov_remote_start()
+	 * and kcov_remote_stop(), hence the check.
+	 */
+	if (kcov->remote)


Strictly saying, it's slightly more complex. kcov could have been disabled and then remote-enabled again, but now it does not want our coverage because it already traces something else...
To resolve this we could add a sequence number to kcov, remember this sequence number in
kcov_remote_start and then compare it here. If sequence numbers don't match, it's not the kcov you are looking you.

xairy · 2018-06-15T16:32:28Z

@dvyukov PTAL

xairy · 2018-06-15T17:22:48Z

Looks like something got broken, looking...

xairy · 2018-06-15T18:58:31Z

OK, so the issue was on the syzkaller side. I didn't wait for a device to disconnect after executing a program. As a result device disconnection could be processed within the same hub_event() call as the device connection in the next program. And so kcov_remote_start() could happen between two programs without remote coverage collection enabled. As a result we don't see coverage from the second program.

xairy · 2018-06-15T19:00:00Z

Fixed by waiting for device disconnection in syzkaller (via a timeout for now). Also put USB kcov annotations under ifdef, in case we ever decide to change the way we collect coverage from USB stack (for example if we decide to collect coverage from individual ports).

xairy · 2018-06-15T19:00:23Z

@dvyukov PTAL

dvyukov · 2018-06-18T08:07:19Z

Also put USB kcov annotations under ifdef, in case we ever decide to change the way we collect coverage from USB stack (for example if we decide to collect coverage from individual ports).

If we decide to collect coverage from individual ports, what will we do? And how the ifdefs will help us?

xairy · 2018-06-18T16:23:47Z

Discussed IRL, removed the new config.

The commit 4af1b64 ("octeontx2-pf: Fix lmtst ID used in aura free") uses the get/put_cpu() to protect the usage of percpu pointer in ->aura_freeptr() callback, but it also unnecessarily disable the preemption for the blockable memory allocation. The commit 87b93b6 ("octeontx2-pf: Avoid use of GFP_KERNEL in atomic context") tried to fix these sleep inside atomic warnings. But it only fix the one for the non-rt kernel. For the rt kernel, we still get the similar warnings like below. BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:46 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 1, name: swapper/0 preempt_count: 1, expected: 0 RCU nest depth: 0, expected: 0 3 locks held by swapper/0/1: #0: ffff800009fc5fe8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock+0x24/0x30 #1: ffff000100c276c0 (&mbox->lock){+.+.}-{3:3}, at: otx2_init_hw_resources+0x8c/0x3a4 #2: ffffffbfef6537e0 (&cpu_rcache->lock){+.+.}-{2:2}, at: alloc_iova_fast+0x1ac/0x2ac Preemption disabled at: [<ffff800008b1908c>] otx2_rq_aura_pool_init+0x14c/0x284 CPU: 20 PID: 1 Comm: swapper/0 Tainted: G W 6.2.0-rc3-rt1-yocto-preempt-rt #1 Hardware name: Marvell OcteonTX CN96XX board (DT) Call trace: dump_backtrace.part.0+0xe8/0xf4 show_stack+0x20/0x30 dump_stack_lvl+0x9c/0xd8 dump_stack+0x18/0x34 __might_resched+0x188/0x224 rt_spin_lock+0x64/0x110 alloc_iova_fast+0x1ac/0x2ac iommu_dma_alloc_iova+0xd4/0x110 __iommu_dma_map+0x80/0x144 iommu_dma_map_page+0xe8/0x260 dma_map_page_attrs+0xb4/0xc0 __otx2_alloc_rbuf+0x90/0x150 otx2_rq_aura_pool_init+0x1c8/0x284 otx2_init_hw_resources+0xe4/0x3a4 otx2_open+0xf0/0x610 __dev_open+0x104/0x224 __dev_change_flags+0x1e4/0x274 dev_change_flags+0x2c/0x7c ic_open_devs+0x124/0x2f8 ip_auto_config+0x180/0x42c do_one_initcall+0x90/0x4dc do_basic_setup+0x10c/0x14c kernel_init_freeable+0x10c/0x13c kernel_init+0x2c/0x140 ret_from_fork+0x10/0x20 Of course, we can shuffle the get/put_cpu() to only wrap the invocation of ->aura_freeptr() as what commit 87b93b6 does. But there are only two ->aura_freeptr() callbacks, otx2_aura_freeptr() and cn10k_aura_freeptr(). There is no usage of perpcu variable in the otx2_aura_freeptr() at all, so the get/put_cpu() seems redundant to it. We can move the get/put_cpu() into the corresponding callback which really has the percpu variable usage and avoid the sprinkling of get/put_cpu() in several places. Fixes: 4af1b64 ("octeontx2-pf: Fix lmtst ID used in aura free") Signed-off-by: Kevin Hao <haokexin@gmail.com> Link: https://lore.kernel.org/r/20230118071300.3271125-1-haokexin@gmail.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Run the following tests on the qemu platform: syzkaller:~# modprobe speakup_audptr input: Speakup as /devices/virtual/input/input4 initialized device: /dev/synth, node (MAJOR 10, MINOR 125) speakup 3.1.6: initialized synth name on entry is: (null) synth probe spk_ttyio_initialise_ldisc failed because tty_kopen_exclusive returned failed (errno -16), then remove the module, we will get a null-ptr-defer problem, as follow: syzkaller:~# modprobe -r speakup_audptr releasing synth audptr BUG: kernel NULL pointer dereference, address: 0000000000000080 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: 0002 [#1] PREEMPT SMP PTI CPU: 2 PID: 204 Comm: modprobe Not tainted 6.1.0-rc6-dirty #1 RIP: 0010:mutex_lock+0x14/0x30 Call Trace: <TASK> spk_ttyio_release+0x19/0x70 [speakup] synth_release.part.6+0xac/0xc0 [speakup] synth_remove+0x56/0x60 [speakup] __x64_sys_delete_module+0x156/0x250 ? fpregs_assert_state_consistent+0x1d/0x50 do_syscall_64+0x37/0x90 entry_SYSCALL_64_after_hwframe+0x63/0xcd </TASK> Modules linked in: speakup_audptr(-) speakup Dumping ftrace buffer: in_synth->dev was not initialized during modprobe, so we add check for in_synth->dev to fix this bug. Fixes: 4f2a81f ("speakup: Reference synth from tty and tty from synth") Cc: stable <stable@kernel.org> Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com> Link: https://lore.kernel.org/r/20221202060633.217364-1-cuigaosheng1@huawei.com Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Commit f1e5250 ("x86/boot: Skip realmode init code when running as Xen PV guest") missed one code path accessing real_mode_header, leading to dereferencing NULL when suspending the system under Xen: [ 348.284004] PM: suspend entry (deep) [ 348.289532] Filesystems sync: 0.005 seconds [ 348.291545] Freezing user space processes ... (elapsed 0.000 seconds) done. [ 348.292457] OOM killer disabled. [ 348.292462] Freezing remaining freezable tasks ... (elapsed 0.104 seconds) done. [ 348.396612] printk: Suspending console(s) (use no_console_suspend to debug) [ 348.749228] PM: suspend devices took 0.352 seconds [ 348.769713] ACPI: EC: interrupt blocked [ 348.816077] BUG: kernel NULL pointer dereference, address: 000000000000001c [ 348.816080] #PF: supervisor read access in kernel mode [ 348.816081] #PF: error_code(0x0000) - not-present page [ 348.816083] PGD 0 P4D 0 [ 348.816086] Oops: 0000 [#1] PREEMPT SMP NOPTI [ 348.816089] CPU: 0 PID: 6764 Comm: systemd-sleep Not tainted 6.1.3-1.fc32.qubes.x86_64 #1 [ 348.816092] Hardware name: Star Labs StarBook/StarBook, BIOS 8.01 07/03/2022 [ 348.816093] RIP: e030:acpi_get_wakeup_address+0xc/0x20 Fix that by adding an optional acpi callback allowing to skip setting the wakeup address, as in the Xen PV case this will be handled by the hypervisor anyway. Fixes: f1e5250 ("x86/boot: Skip realmode init code when running as Xen PV guest") Reported-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com> Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Link: https://lore.kernel.org/all/20230117155724.22940-1-jgross%40suse.com

The vmci_dispatch_dgs() tasklet function calls vmci_read_data() which uses wait_event() resulting in invalid sleep in an atomic context (and therefore potentially in a deadlock). Use threaded irqs to fix this issue and completely remove usage of tasklets. [ 20.264639] BUG: sleeping function called from invalid context at drivers/misc/vmw_vmci/vmci_guest.c:145 [ 20.264643] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 762, name: vmtoolsd [ 20.264645] preempt_count: 101, expected: 0 [ 20.264646] RCU nest depth: 0, expected: 0 [ 20.264647] 1 lock held by vmtoolsd/762: [ 20.264648] #0: ffff0000874ae440 (sk_lock-AF_VSOCK){+.+.}-{0:0}, at: vsock_connect+0x60/0x330 [vsock] [ 20.264658] Preemption disabled at: [ 20.264659] [<ffff80000151d7d8>] vmci_send_datagram+0x44/0xa0 [vmw_vmci] [ 20.264665] CPU: 0 PID: 762 Comm: vmtoolsd Not tainted 5.19.0-0.rc8.20220727git39c3c396f813.60.fc37.aarch64 #1 [ 20.264667] Hardware name: VMware, Inc. VBSA/VBSA, BIOS VEFI 12/31/2020 [ 20.264668] Call trace: [ 20.264669] dump_backtrace+0xc4/0x130 [ 20.264672] show_stack+0x24/0x80 [ 20.264673] dump_stack_lvl+0x88/0xb4 [ 20.264676] dump_stack+0x18/0x34 [ 20.264677] __might_resched+0x1a0/0x280 [ 20.264679] __might_sleep+0x58/0x90 [ 20.264681] vmci_read_data+0x74/0x120 [vmw_vmci] [ 20.264683] vmci_dispatch_dgs+0x64/0x204 [vmw_vmci] [ 20.264686] tasklet_action_common.constprop.0+0x13c/0x150 [ 20.264688] tasklet_action+0x40/0x50 [ 20.264689] __do_softirq+0x23c/0x6b4 [ 20.264690] __irq_exit_rcu+0x104/0x214 [ 20.264691] irq_exit_rcu+0x1c/0x50 [ 20.264693] el1_interrupt+0x38/0x6c [ 20.264695] el1h_64_irq_handler+0x18/0x24 [ 20.264696] el1h_64_irq+0x68/0x6c [ 20.264697] preempt_count_sub+0xa4/0xe0 [ 20.264698] _raw_spin_unlock_irqrestore+0x64/0xb0 [ 20.264701] vmci_send_datagram+0x7c/0xa0 [vmw_vmci] [ 20.264703] vmci_datagram_dispatch+0x84/0x100 [vmw_vmci] [ 20.264706] vmci_datagram_send+0x2c/0x40 [vmw_vmci] [ 20.264709] vmci_transport_send_control_pkt+0xb8/0x120 [vmw_vsock_vmci_transport] [ 20.264711] vmci_transport_connect+0x40/0x7c [vmw_vsock_vmci_transport] [ 20.264713] vsock_connect+0x278/0x330 [vsock] [ 20.264715] __sys_connect_file+0x8c/0xc0 [ 20.264718] __sys_connect+0x84/0xb4 [ 20.264720] __arm64_sys_connect+0x2c/0x3c [ 20.264721] invoke_syscall+0x78/0x100 [ 20.264723] el0_svc_common.constprop.0+0x68/0x124 [ 20.264724] do_el0_svc+0x38/0x4c [ 20.264725] el0_svc+0x60/0x180 [ 20.264726] el0t_64_sync_handler+0x11c/0x150 [ 20.264728] el0t_64_sync+0x190/0x194 Signed-off-by: Vishnu Dasa <vdasa@vmware.com> Suggested-by: Zack Rusin <zackr@vmware.com> Reported-by: Nadav Amit <namit@vmware.com> Reported-by: Nathan Chancellor <nathan@kernel.org> Tested-by: Nathan Chancellor <nathan@kernel.org> Fixes: 463713e ("VMCI: dma dg: add support for DMA datagrams receive") Cc: <stable@vger.kernel.org> # v5.18+ Cc: VMware PV-Drivers Reviewers <pv-drivers@vmware.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Bryan Tan <bryantan@vmware.com> Reviewed-by: Bryan Tan <bryantan@vmware.com> Reviewed-by: Zack Rusin <zackr@vmware.com> Link: https://lore.kernel.org/r/20221130070511.46558-1-vdasa@vmware.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The page_pool_release_page was used when freeing rx buffers, and this function just unmaps the page (if mapped) and does not recycle the page. So after hundreds of down/up the eth0, the system will out of memory. For more details, please refer to the following reproduce steps and bug logs. To solve this issue and refer to the doc of page pool, the page_pool_put_full_page should be used to replace page_pool_release_page. Because this API will try to recycle the page if the page refcnt equal to 1. After testing 20000 times, the issue can not be reproduced anymore (about testing 391 times the issue will occur on i.MX8MN-EVK before). Reproduce steps: Create the test script and run the script. The script content is as follows: LOOPS=20000 i=1 while [ $i -le $LOOPS ] do echo "TINFO:ENET $curface up and down test $i times" org_macaddr=$(cat /sys/class/net/eth0/address) ifconfig eth0 down ifconfig eth0 hw ether $org_macaddr up i=$(expr $i + 1) done sleep 5 if cat /sys/class/net/eth0/operstate | grep 'up';then echo "TEST PASS" else echo "TEST FAIL" fi Bug detail logs: TINFO:ENET up and down test 391 times [ 850.471205] Qualcomm Atheros AR8031/AR8033 30be0000.ethernet-1:00: attached PHY driver (mii_bus:phy_addr=30be0000.ethernet-1:00, irq=POLL) [ 853.535318] IPv6: ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready [ 853.541694] fec 30be0000.ethernet eth0: Link is Up - 1Gbps/Full - flow control rx/tx [ 870.590531] page_pool_release_retry() stalled pool shutdown 199 inflight 60 sec [ 931.006557] page_pool_release_retry() stalled pool shutdown 199 inflight 120 sec TINFO:ENET up and down test 392 times [ 991.426544] page_pool_release_retry() stalled pool shutdown 192 inflight 181 sec [ 1051.838531] page_pool_release_retry() stalled pool shutdown 170 inflight 241 sec [ 1093.751217] Qualcomm Atheros AR8031/AR8033 30be0000.ethernet-1:00: attached PHY driver (mii_bus:phy_addr=30be0000.ethernet-1:00, irq=POLL) [ 1096.446520] page_pool_release_retry() stalled pool shutdown 308 inflight 60 sec [ 1096.831245] fec 30be0000.ethernet eth0: Link is Up - 1Gbps/Full - flow control rx/tx [ 1096.839092] IPv6: ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready [ 1112.254526] page_pool_release_retry() stalled pool shutdown 103 inflight 302 sec [ 1156.862533] page_pool_release_retry() stalled pool shutdown 308 inflight 120 sec [ 1172.674516] page_pool_release_retry() stalled pool shutdown 103 inflight 362 sec [ 1217.278532] page_pool_release_retry() stalled pool shutdown 308 inflight 181 sec TINFO:ENET up and down test 393 times [ 1233.086535] page_pool_release_retry() stalled pool shutdown 103 inflight 422 sec [ 1277.698513] page_pool_release_retry() stalled pool shutdown 308 inflight 241 sec [ 1293.502525] page_pool_release_retry() stalled pool shutdown 86 inflight 483 sec [ 1338.110518] page_pool_release_retry() stalled pool shutdown 308 inflight 302 sec [ 1353.918540] page_pool_release_retry() stalled pool shutdown 32 inflight 543 sec [ 1361.179205] Qualcomm Atheros AR8031/AR8033 30be0000.ethernet-1:00: attached PHY driver (mii_bus:phy_addr=30be0000.ethernet-1:00, irq=POLL) [ 1364.255298] fec 30be0000.ethernet eth0: Link is Up - 1Gbps/Full - flow control rx/tx [ 1364.263189] IPv6: ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready [ 1371.998532] page_pool_release_retry() stalled pool shutdown 310 inflight 60 sec [ 1398.530542] page_pool_release_retry() stalled pool shutdown 308 inflight 362 sec [ 1414.334539] page_pool_release_retry() stalled pool shutdown 16 inflight 604 sec [ 1432.414520] page_pool_release_retry() stalled pool shutdown 310 inflight 120 sec [ 1458.942523] page_pool_release_retry() stalled pool shutdown 308 inflight 422 sec [ 1474.750521] page_pool_release_retry() stalled pool shutdown 16 inflight 664 sec TINFO:ENET up and down test 394 times [ 1492.830522] page_pool_release_retry() stalled pool shutdown 310 inflight 181 sec [ 1519.358519] page_pool_release_retry() stalled pool shutdown 308 inflight 483 sec [ 1535.166545] page_pool_release_retry() stalled pool shutdown 2 inflight 724 sec [ 1537.090278] eth_test2.sh invoked oom-killer: gfp_mask=0x400dc0(GFP_KERNEL_ACCOUNT|__GFP_ZERO), order=0, oom_score_adj=0 [ 1537.101192] CPU: 3 PID: 2379 Comm: eth_test2.sh Tainted: G C 6.1.1+g56321e101aca #1 [ 1537.110249] Hardware name: NXP i.MX8MNano EVK board (DT) [ 1537.115561] Call trace: [ 1537.118005] dump_backtrace.part.0+0xe0/0xf0 [ 1537.122289] show_stack+0x18/0x40 [ 1537.125608] dump_stack_lvl+0x64/0x80 [ 1537.129276] dump_stack+0x18/0x34 [ 1537.132592] dump_header+0x44/0x208 [ 1537.136083] oom_kill_process+0x2b4/0x2c0 [ 1537.140097] out_of_memory+0xe4/0x594 [ 1537.143766] __alloc_pages+0xb68/0xd00 [ 1537.147521] alloc_pages+0xac/0x160 [ 1537.151013] __get_free_pages+0x14/0x40 [ 1537.154851] pgd_alloc+0x1c/0x30 [ 1537.158082] mm_init+0xf8/0x1d0 [ 1537.161228] mm_alloc+0x48/0x60 [ 1537.164368] alloc_bprm+0x7c/0x240 [ 1537.167777] do_execveat_common.isra.0+0x70/0x240 [ 1537.172486] __arm64_sys_execve+0x40/0x54 [ 1537.176502] invoke_syscall+0x48/0x114 [ 1537.180255] el0_svc_common.constprop.0+0xcc/0xec [ 1537.184964] do_el0_svc+0x2c/0xd0 [ 1537.188280] el0_svc+0x2c/0x84 [ 1537.191340] el0t_64_sync_handler+0xf4/0x120 [ 1537.195613] el0t_64_sync+0x18c/0x190 [ 1537.199334] Mem-Info: [ 1537.201620] active_anon:342 inactive_anon:10343 isolated_anon:0 [ 1537.201620] active_file:54 inactive_file:112 isolated_file:0 [ 1537.201620] unevictable:0 dirty:0 writeback:0 [ 1537.201620] slab_reclaimable:2620 slab_unreclaimable:7076 [ 1537.201620] mapped:1489 shmem:2473 pagetables:466 [ 1537.201620] sec_pagetables:0 bounce:0 [ 1537.201620] kernel_misc_reclaimable:0 [ 1537.201620] free:136672 free_pcp:96 free_cma:129241 [ 1537.240419] Node 0 active_anon:1368kB inactive_anon:41372kB active_file:216kB inactive_file:5052kB unevictable:0kB isolated(anon):0kB isolated(file):0kB s [ 1537.271422] Node 0 DMA free:541636kB boost:0kB min:30000kB low:37500kB high:45000kB reserved_highatomic:0KB active_anon:1368kB inactive_anon:41372kB actiB [ 1537.300219] lowmem_reserve[]: 0 0 0 0 [ 1537.303929] Node 0 DMA: 1015*4kB (UMEC) 743*8kB (UMEC) 417*16kB (UMEC) 235*32kB (UMEC) 116*64kB (UMEC) 25*128kB (UMEC) 4*256kB (UC) 2*512kB (UC) 0*1024kBB [ 1537.323938] Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=1048576kB [ 1537.332708] Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=32768kB [ 1537.341292] Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=2048kB [ 1537.349776] Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=64kB [ 1537.358087] 2939 total pagecache pages [ 1537.361876] 0 pages in swap cache [ 1537.365229] Free swap = 0kB [ 1537.368147] Total swap = 0kB [ 1537.371065] 516096 pages RAM [ 1537.373959] 0 pages HighMem/MovableOnly [ 1537.377834] 17302 pages reserved [ 1537.381103] 163840 pages cma reserved [ 1537.384809] 0 pages hwpoisoned [ 1537.387902] Tasks state (memory values in pages): [ 1537.392652] [ pid ] uid tgid total_vm rss pgtables_bytes swapents oom_score_adj name [ 1537.401356] [ 201] 993 201 1130 72 45056 0 0 rpcbind [ 1537.409772] [ 202] 0 202 4529 1640 77824 0 -250 systemd-journal [ 1537.418861] [ 222] 0 222 4691 801 69632 0 -1000 systemd-udevd [ 1537.427787] [ 248] 994 248 20914 130 65536 0 0 systemd-timesyn [ 1537.436884] [ 497] 0 497 620 31 49152 0 0 atd [ 1537.444938] [ 500] 0 500 854 77 53248 0 0 crond [ 1537.453165] [ 503] 997 503 1470 160 49152 0 -900 dbus-daemon [ 1537.461908] [ 505] 0 505 633 24 40960 0 0 firmwared [ 1537.470491] [ 513] 0 513 2507 180 61440 0 0 ofonod [ 1537.478800] [ 514] 990 514 69640 137 81920 0 0 parsec [ 1537.487120] [ 533] 0 533 599 39 40960 0 0 syslogd [ 1537.495518] [ 534] 0 534 4546 148 65536 0 0 systemd-logind [ 1537.504560] [ 535] 0 535 690 24 45056 0 0 tee-supplicant [ 1537.513564] [ 540] 996 540 2769 168 61440 0 0 systemd-network [ 1537.522680] [ 566] 0 566 3878 228 77824 0 0 connmand [ 1537.531168] [ 645] 998 645 1538 133 57344 0 0 avahi-daemon [ 1537.540004] [ 646] 998 646 1461 64 57344 0 0 avahi-daemon [ 1537.548846] [ 648] 992 648 781 41 45056 0 0 rpc.statd [ 1537.557415] [ 650] 64371 650 590 23 45056 0 0 ninfod [ 1537.565754] [ 653] 61563 653 555 24 45056 0 0 rdisc [ 1537.573971] [ 655] 0 655 374569 2999 290816 0 -999 containerd [ 1537.582621] [ 658] 0 658 1311 20 49152 0 0 agetty [ 1537.590922] [ 663] 0 663 1529 97 49152 0 0 login [ 1537.599138] [ 666] 0 666 3430 202 69632 0 0 wpa_supplicant [ 1537.608147] [ 667] 0 667 2344 96 61440 0 0 systemd-userdbd [ 1537.617240] [ 677] 0 677 2964 314 65536 0 100 systemd [ 1537.625651] [ 679] 0 679 3720 646 73728 0 100 (sd-pam) [ 1537.634138] [ 687] 0 687 1289 403 45056 0 0 sh [ 1537.642108] [ 789] 0 789 970 93 45056 0 0 eth_test2.sh [ 1537.650955] [ 2355] 0 2355 2346 94 61440 0 0 systemd-userwor [ 1537.660046] [ 2356] 0 2356 2346 94 61440 0 0 systemd-userwor [ 1537.669137] [ 2358] 0 2358 2346 95 57344 0 0 systemd-userwor [ 1537.678258] [ 2379] 0 2379 970 93 45056 0 0 eth_test2.sh [ 1537.687098] oom-kill:constraint=CONSTRAINT_NONE,nodemask=(null),cpuset=/,mems_allowed=0,global_oom,task_memcg=/user.slice/user-0.slice/user@0.service,tas0 [ 1537.703009] Out of memory: Killed process 679 ((sd-pam)) total-vm:14880kB, anon-rss:2584kB, file-rss:0kB, shmem-rss:0kB, UID:0 pgtables:72kB oom_score_ad0 [ 1553.246526] page_pool_release_retry() stalled pool shutdown 310 inflight 241 sec Fixes: 95698ff ("net: fec: using page pool to manage RX buffers") Signed-off-by: Wei Fang <wei.fang@nxp.com> Reviewed-by: shenwei wang <Shenwei.wang@nxp.com> Reviewed-by: Jesse Brandeburg <jesse.brandeburg@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>

Set kprobe at 'jalr 1140(ra)' of vfs_write results in the following crash: [ 32.092235] Unable to handle kernel access to user memory without uaccess routines at virtual address 00aaaaaad77b1170 [ 32.093115] Oops [#1] [ 32.093251] Modules linked in: [ 32.093626] CPU: 0 PID: 135 Comm: ftracetest Not tainted 6.2.0-rc2-00013-gb0aa5e5df0cb-dirty torvalds#16 [ 32.093985] Hardware name: riscv-virtio,qemu (DT) [ 32.094280] epc : ksys_read+0x88/0xd6 [ 32.094855] ra : ksys_read+0xc0/0xd6 [ 32.095016] epc : ffffffff801cda80 ra : ffffffff801cdab8 sp : ff20000000d7bdc0 [ 32.095227] gp : ffffffff80f14000 tp : ff60000080f9cb40 t0 : ffffffff80f13e80 [ 32.095500] t1 : ffffffff8000c29c t2 : ffffffff800dbc54 s0 : ff20000000d7be60 [ 32.095716] s1 : 0000000000000000 a0 : ffffffff805a64ae a1 : ffffffff80a83708 [ 32.095921] a2 : ffffffff80f160a0 a3 : 0000000000000000 a4 : f229b0afdb165300 [ 32.096171] a5 : f229b0afdb165300 a6 : ffffffff80eeebd0 a7 : 00000000000003ff [ 32.096411] s2 : ff6000007ff76800 s3 : fffffffffffffff7 s4 : 00aaaaaad77b1170 [ 32.096638] s5 : ffffffff80f160a0 s6 : ff6000007ff76800 s7 : 0000000000000030 [ 32.096865] s8 : 00ffffffc3d97be0 s9 : 0000000000000007 s10: 00aaaaaad77c9410 [ 32.097092] s11: 0000000000000000 t3 : ffffffff80f13e48 t4 : ffffffff8000c29c [ 32.097317] t5 : ffffffff8000c29c t6 : ffffffff800dbc54 [ 32.097505] status: 0000000200000120 badaddr: 00aaaaaad77b1170 cause: 000000000000000d [ 32.098011] [<ffffffff801cdb72>] ksys_write+0x6c/0xd6 [ 32.098222] [<ffffffff801cdc06>] sys_write+0x2a/0x38 [ 32.098405] [<ffffffff80003c76>] ret_from_syscall+0x0/0x2 Since the rs1 and rd might be the same one, such as 'jalr 1140(ra)', hence it requires obtaining the target address from rs1 followed by updating rd. Fixes: c22b0bc ("riscv: Add kprobes supported") Signed-off-by: Liao Chang <liaochang1@huawei.com> Reviewed-by: Guo Ren <guoren@kernel.org> Link: https://lore.kernel.org/r/20230116064342.2092136-1-liaochang1@huawei.com [Palmer: Pick Guo's cleanup] Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

commit 69403ba upstream. ieee80211_tx_ba_session_handle_start() may get NULL for sdata when a deauthentication is ongoing. Here a trace triggering the race with the hostapd test multi_ap_fronthaul_on_ap: (gdb) list *drv_ampdu_action+0x46 0x8b16 is in drv_ampdu_action (net/mac80211/driver-ops.c:396). 391 int ret = -EOPNOTSUPP; 392 393 might_sleep(); 394 395 sdata = get_bss_sdata(sdata); 396 if (!check_sdata_in_driver(sdata)) 397 return -EIO; 398 399 trace_drv_ampdu_action(local, sdata, params); 400 wlan0: moving STA 02:00:00:00:03:00 to state 3 wlan0: associated wlan0: deauthenticating from 02:00:00:00:03:00 by local choice (Reason: 3=DEAUTH_LEAVING) wlan3.sta1: Open BA session requested for 02:00:00:00:00:00 tid 0 wlan3.sta1: dropped frame to 02:00:00:00:00:00 (unauthorized port) wlan0: moving STA 02:00:00:00:03:00 to state 2 wlan0: moving STA 02:00:00:00:03:00 to state 1 wlan0: Removed STA 02:00:00:00:03:00 wlan0: Destroyed STA 02:00:00:00:03:00 BUG: unable to handle page fault for address: fffffffffffffb48 PGD 11814067 P4D 11814067 PUD 11816067 PMD 0 Oops: 0000 [#1] PREEMPT SMP PTI CPU: 2 PID: 133397 Comm: kworker/u16:1 Tainted: G W 6.1.0-rc8-wt+ torvalds#59 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.0-20220807_005459-localhost 04/01/2014 Workqueue: phy3 ieee80211_ba_session_work [mac80211] RIP: 0010:drv_ampdu_action+0x46/0x280 [mac80211] Code: 53 48 89 f3 be 89 01 00 00 e8 d6 43 bf ef e8 21 46 81 f0 83 bb a0 1b 00 00 04 75 0e 48 8b 9b 28 0d 00 00 48 81 eb 10 0e 00 00 <8b> 93 58 09 00 00 f6 c2 20 0f 84 3b 01 00 00 8b 05 dd 1c 0f 00 85 RSP: 0018:ffffc900025ebd20 EFLAGS: 00010287 RAX: 0000000000000000 RBX: fffffffffffff1f0 RCX: ffff888102228240 RDX: 0000000080000000 RSI: ffffffff918c5de0 RDI: ffff888102228b40 RBP: ffffc900025ebd40 R08: 0000000000000001 R09: 0000000000000001 R10: 0000000000000001 R11: 0000000000000000 R12: ffff888118c18ec0 R13: 0000000000000000 R14: ffffc900025ebd60 R15: ffff888018b7efb8 FS: 0000000000000000(0000) GS:ffff88817a600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: fffffffffffffb48 CR3: 0000000105228006 CR4: 0000000000170ee0 Call Trace: <TASK> ieee80211_tx_ba_session_handle_start+0xd0/0x190 [mac80211] ieee80211_ba_session_work+0xff/0x2e0 [mac80211] process_one_work+0x29f/0x620 worker_thread+0x4d/0x3d0 ? process_one_work+0x620/0x620 kthread+0xfb/0x120 ? kthread_complete_and_exit+0x20/0x20 ret_from_fork+0x22/0x30 </TASK> Signed-off-by: Alexander Wetzel <alexander@wetzel-home.de> Link: https://lore.kernel.org/r/20221230121850.218810-2-alexander@wetzel-home.de Cc: stable@vger.kernel.org Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

…ction commit 57054fe upstream. Since there is no protection for vd, a kernel panic will be triggered here in exceptional cases. You can refer to the processing of axi_chan_block_xfer_complete function The triggered kernel panic is as follows: [ 67.848444] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000060 [ 67.848447] Mem abort info: [ 67.848449] ESR = 0x96000004 [ 67.848451] EC = 0x25: DABT (current EL), IL = 32 bits [ 67.848454] SET = 0, FnV = 0 [ 67.848456] EA = 0, S1PTW = 0 [ 67.848458] Data abort info: [ 67.848460] ISV = 0, ISS = 0x00000004 [ 67.848462] CM = 0, WnR = 0 [ 67.848465] user pgtable: 4k pages, 48-bit VAs, pgdp=00000800c4c0b000 [ 67.848468] [0000000000000060] pgd=0000000000000000, p4d=0000000000000000 [ 67.848472] Internal error: Oops: 96000004 [#1] SMP [ 67.848475] Modules linked in: dmatest [ 67.848479] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.10.100-emu_x2rc+ torvalds#11 [ 67.848483] pstate: 62000085 (nZCv daIf -PAN -UAO +TCO BTYPE=--) [ 67.848487] pc : axi_chan_handle_err+0xc4/0x230 [ 67.848491] lr : axi_chan_handle_err+0x30/0x230 [ 67.848493] sp : ffff0803fe55ae50 [ 67.848495] x29: ffff0803fe55ae50 x28: ffff800011212200 [ 67.848500] x27: ffff0800c42c0080 x26: ffff0800c097c080 [ 67.848504] x25: ffff800010d33880 x24: ffff80001139d850 [ 67.848508] x23: ffff0800c097c168 x22: 0000000000000000 [ 67.848512] x21: 0000000000000080 x20: 0000000000002000 [ 67.848517] x19: ffff0800c097c080 x18: 0000000000000000 [ 67.848521] x17: 0000000000000000 x16: 0000000000000000 [ 67.848525] x15: 0000000000000000 x14: 0000000000000000 [ 67.848529] x13: 0000000000000000 x12: 0000000000000040 [ 67.848533] x11: ffff0800c0400248 x10: ffff0800c040024a [ 67.848538] x9 : ffff800010576cd4 x8 : ffff0800c0400270 [ 67.848542] x7 : 0000000000000000 x6 : ffff0800c04003e0 [ 67.848546] x5 : ffff0800c0400248 x4 : ffff0800c4294480 [ 67.848550] x3 : dead000000000100 x2 : dead000000000122 [ 67.848555] x1 : 0000000000000100 x0 : ffff0800c097c168 [ 67.848559] Call trace: [ 67.848562] axi_chan_handle_err+0xc4/0x230 [ 67.848566] dw_axi_dma_interrupt+0xf4/0x590 [ 67.848569] __handle_irq_event_percpu+0x60/0x220 [ 67.848573] handle_irq_event+0x64/0x120 [ 67.848576] handle_fasteoi_irq+0xc4/0x220 [ 67.848580] __handle_domain_irq+0x80/0xe0 [ 67.848583] gic_handle_irq+0xc0/0x138 [ 67.848585] el1_irq+0xc8/0x180 [ 67.848588] arch_cpu_idle+0x14/0x2c [ 67.848591] default_idle_call+0x40/0x16c [ 67.848594] do_idle+0x1f0/0x250 [ 67.848597] cpu_startup_entry+0x2c/0x60 [ 67.848600] rest_init+0xc0/0xcc [ 67.848603] arch_call_rest_init+0x14/0x1c [ 67.848606] start_kernel+0x4cc/0x500 [ 67.848610] Code: eb0002ff 9a9f12d6 f2fbd5a2 f2fbd5a3 (a94602c1) [ 67.848613] ---[ end trace 585a97036f88203a ]--- Signed-off-by: Shawn.Shao <shawn.shao@jaguarmicro.com> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20230112055802.1764-1-shawn.shao@jaguarmicro.com Signed-off-by: Vinod Koul <vkoul@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 7633355 upstream. If nilfs2 reads a corrupted disk image and tries to reads a b-tree node block by calling __nilfs_btree_get_block() against an invalid virtual block address, it returns -ENOENT because conversion of the virtual block address to a disk block address fails. However, this return value is the same as the internal code that b-tree lookup routines return to indicate that the block being searched does not exist, so functions that operate on that b-tree may misbehave. When nilfs_btree_insert() receives this spurious 'not found' code from nilfs_btree_do_lookup(), it misunderstands that the 'not found' check was successful and continues the insert operation using incomplete lookup path data, causing the following crash: general protection fault, probably for non-canonical address 0xdffffc0000000005: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f] ... RIP: 0010:nilfs_btree_get_nonroot_node fs/nilfs2/btree.c:418 [inline] RIP: 0010:nilfs_btree_prepare_insert fs/nilfs2/btree.c:1077 [inline] RIP: 0010:nilfs_btree_insert+0x6d3/0x1c10 fs/nilfs2/btree.c:1238 Code: bc 24 80 00 00 00 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 ff e8 4b 02 92 fe 4d 8b 3f 49 83 c7 28 4c 89 f8 48 c1 e8 03 <42> 80 3c 28 00 74 08 4c 89 ff e8 2e 02 92 fe 4d 8b 3f 49 83 c7 02 ... Call Trace: <TASK> nilfs_bmap_do_insert fs/nilfs2/bmap.c:121 [inline] nilfs_bmap_insert+0x20d/0x360 fs/nilfs2/bmap.c:147 nilfs_get_block+0x414/0x8d0 fs/nilfs2/inode.c:101 __block_write_begin_int+0x54c/0x1a80 fs/buffer.c:1991 __block_write_begin fs/buffer.c:2041 [inline] block_write_begin+0x93/0x1e0 fs/buffer.c:2102 nilfs_write_begin+0x9c/0x110 fs/nilfs2/inode.c:261 generic_perform_write+0x2e4/0x5e0 mm/filemap.c:3772 __generic_file_write_iter+0x176/0x400 mm/filemap.c:3900 generic_file_write_iter+0xab/0x310 mm/filemap.c:3932 call_write_iter include/linux/fs.h:2186 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x7dc/0xc50 fs/read_write.c:584 ksys_write+0x177/0x2a0 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd ... </TASK> This patch fixes the root cause of this problem by replacing the error code that __nilfs_btree_get_block() returns on block address conversion failure from -ENOENT to another internal code -EINVAL which means that the b-tree metadata is corrupted. By returning -EINVAL, it propagates without glitches, and for all relevant b-tree operations, functions in the upper bmap layer output an error message indicating corrupted b-tree metadata via nilfs_bmap_convert_error(), and code -EIO will be eventually returned as it should be. Link: https://lkml.kernel.org/r/000000000000bd89e205f0e38355@google.com Link: https://lkml.kernel.org/r/20230105055356.8811-1-konishi.ryusuke@gmail.com Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com> Reported-by: syzbot+ede796cecd5296353515@syzkaller.appspotmail.com Tested-by: Ryusuke Konishi <konishi.ryusuke@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

…ter deref commit b7adbf9 upstream. If we have one task trying to start the quota rescan worker while another one is trying to disable quotas, we can end up hitting a race that results in the quota rescan worker doing a NULL pointer dereference. The steps for this are the following: 1) Quotas are enabled; 2) Task A calls the quota rescan ioctl and enters btrfs_qgroup_rescan(). It calls qgroup_rescan_init() which returns 0 (success) and then joins a transaction and commits it; 3) Task B calls the quota disable ioctl and enters btrfs_quota_disable(). It clears the bit BTRFS_FS_QUOTA_ENABLED from fs_info->flags and calls btrfs_qgroup_wait_for_completion(), which returns immediately since the rescan worker is not yet running. Then it starts a transaction and locks fs_info->qgroup_ioctl_lock; 4) Task A queues the rescan worker, by calling btrfs_queue_work(); 5) The rescan worker starts, and calls rescan_should_stop() at the start of its while loop, which results in 0 iterations of the loop, since the flag BTRFS_FS_QUOTA_ENABLED was cleared from fs_info->flags by task B at step 3); 6) Task B sets fs_info->quota_root to NULL; 7) The rescan worker tries to start a transaction and uses fs_info->quota_root as the root argument for btrfs_start_transaction(). This results in a NULL pointer dereference down the call chain of btrfs_start_transaction(). The stack trace is something like the one reported in Link tag below: general protection fault, probably for non-canonical address 0xdffffc0000000041: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000208-0x000000000000020f] CPU: 1 PID: 34 Comm: kworker/u4:2 Not tainted 6.1.0-syzkaller-13872-gb6bb9676f216 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 Workqueue: btrfs-qgroup-rescan btrfs_work_helper RIP: 0010:start_transaction+0x48/0x10f0 fs/btrfs/transaction.c:564 Code: 48 89 fb 48 (...) RSP: 0018:ffffc90000ab7ab0 EFLAGS: 00010206 RAX: 0000000000000041 RBX: 0000000000000208 RCX: ffff88801779ba80 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: dffffc0000000000 R08: 0000000000000001 R09: fffff52000156f5d R10: fffff52000156f5d R11: 1ffff92000156f5c R12: 0000000000000000 R13: 0000000000000001 R14: 0000000000000001 R15: 0000000000000003 FS: 0000000000000000(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f2bea75b718 CR3: 000000001d0cc000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> btrfs_qgroup_rescan_worker+0x3bb/0x6a0 fs/btrfs/qgroup.c:3402 btrfs_work_helper+0x312/0x850 fs/btrfs/async-thread.c:280 process_one_work+0x877/0xdb0 kernel/workqueue.c:2289 worker_thread+0xb14/0x1330 kernel/workqueue.c:2436 kthread+0x266/0x300 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 </TASK> Modules linked in: So fix this by having the rescan worker function not attempt to start a transaction if it didn't do any rescan work. Reported-by: syzbot+96977faa68092ad382c4@syzkaller.appspotmail.com Link: https://lore.kernel.org/linux-btrfs/000000000000e5454b05f065a803@google.com/ Fixes: e804861 ("btrfs: fix deadlock between quota disable and qgroup rescan worker") CC: stable@vger.kernel.org # 5.4+ Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 5abbeeb upstream. Run the following tests on the qemu platform: syzkaller:~# modprobe speakup_audptr input: Speakup as /devices/virtual/input/input4 initialized device: /dev/synth, node (MAJOR 10, MINOR 125) speakup 3.1.6: initialized synth name on entry is: (null) synth probe spk_ttyio_initialise_ldisc failed because tty_kopen_exclusive returned failed (errno -16), then remove the module, we will get a null-ptr-defer problem, as follow: syzkaller:~# modprobe -r speakup_audptr releasing synth audptr BUG: kernel NULL pointer dereference, address: 0000000000000080 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: 0002 [#1] PREEMPT SMP PTI CPU: 2 PID: 204 Comm: modprobe Not tainted 6.1.0-rc6-dirty #1 RIP: 0010:mutex_lock+0x14/0x30 Call Trace: <TASK> spk_ttyio_release+0x19/0x70 [speakup] synth_release.part.6+0xac/0xc0 [speakup] synth_remove+0x56/0x60 [speakup] __x64_sys_delete_module+0x156/0x250 ? fpregs_assert_state_consistent+0x1d/0x50 do_syscall_64+0x37/0x90 entry_SYSCALL_64_after_hwframe+0x63/0xcd </TASK> Modules linked in: speakup_audptr(-) speakup Dumping ftrace buffer: in_synth->dev was not initialized during modprobe, so we add check for in_synth->dev to fix this bug. Fixes: 4f2a81f ("speakup: Reference synth from tty and tty from synth") Cc: stable <stable@kernel.org> Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com> Link: https://lore.kernel.org/r/20221202060633.217364-1-cuigaosheng1@huawei.com Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 80f8a66 upstream. This reverts commit 13e5afd. ieee80211_if_free() is already called from free_netdev(ndev) because ndev->priv_destructor == ieee80211_if_free syzbot reported: general protection fault, probably for non-canonical address 0xdffffc0000000004: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000020-0x0000000000000027] CPU: 0 PID: 10041 Comm: syz-executor.0 Not tainted 6.2.0-rc2-syzkaller-00388-g55b98837e37d #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 RIP: 0010:pcpu_get_page_chunk mm/percpu.c:262 [inline] RIP: 0010:pcpu_chunk_addr_search mm/percpu.c:1619 [inline] RIP: 0010:free_percpu mm/percpu.c:2271 [inline] RIP: 0010:free_percpu+0x186/0x10f0 mm/percpu.c:2254 Code: 80 3c 02 00 0f 85 f5 0e 00 00 48 8b 3b 48 01 ef e8 cf b3 0b 00 48 ba 00 00 00 00 00 fc ff df 48 8d 78 20 48 89 f9 48 c1 e9 03 <80> 3c 11 00 0f 85 3b 0e 00 00 48 8b 58 20 48 b8 00 00 00 00 00 fc RSP: 0018:ffffc90004ba7068 EFLAGS: 00010002 RAX: 0000000000000000 RBX: ffff88823ffe2b80 RCX: 0000000000000004 RDX: dffffc0000000000 RSI: ffffffff81c1f4e7 RDI: 0000000000000020 RBP: ffffe8fffe8fc220 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000000 R11: 1ffffffff2179ab2 R12: ffff8880b983d000 R13: 0000000000000003 R14: 0000607f450fc220 R15: ffff88823ffe2988 FS: 00007fcb349de700(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b32220000 CR3: 000000004914f000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> netdev_run_todo+0x6bf/0x1100 net/core/dev.c:10352 ieee80211_register_hw+0x2663/0x4040 net/mac80211/main.c:1411 mac80211_hwsim_new_radio+0x2537/0x4d80 drivers/net/wireless/mac80211_hwsim.c:4583 hwsim_new_radio_nl+0xa09/0x10f0 drivers/net/wireless/mac80211_hwsim.c:5176 genl_family_rcv_msg_doit.isra.0+0x1e6/0x2d0 net/netlink/genetlink.c:968 genl_family_rcv_msg net/netlink/genetlink.c:1048 [inline] genl_rcv_msg+0x4ff/0x7e0 net/netlink/genetlink.c:1065 netlink_rcv_skb+0x165/0x440 net/netlink/af_netlink.c:2564 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1076 netlink_unicast_kernel net/netlink/af_netlink.c:1330 [inline] netlink_unicast+0x547/0x7f0 net/netlink/af_netlink.c:1356 netlink_sendmsg+0x91b/0xe10 net/netlink/af_netlink.c:1932 sock_sendmsg_nosec net/socket.c:714 [inline] sock_sendmsg+0xd3/0x120 net/socket.c:734 ____sys_sendmsg+0x712/0x8c0 net/socket.c:2476 ___sys_sendmsg+0x110/0x1b0 net/socket.c:2530 __sys_sendmsg+0xf7/0x1c0 net/socket.c:2559 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Reported-by: syzbot <syzkaller@googlegroups.com> Fixes: 13e5afd ("wifi: mac80211: fix memory leak in ieee80211_if_add()") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Zhengchao Shao <shaozhengchao@huawei.com> Cc: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Kalle Valo <kvalo@kernel.org> Link: https://lore.kernel.org/r/20230113124326.3533978-1-edumazet@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

[ Upstream commit 3c46372 ] This lockdep splat says it better than I could: ================================ WARNING: inconsistent lock state 6.2.0-rc2-07010-ga9b9500ffaac-dirty torvalds#967 Not tainted -------------------------------- inconsistent {IN-SOFTIRQ-W} -> {SOFTIRQ-ON-W} usage. kworker/1:3/179 [HC0[0]:SC0[0]:HE1:SE1] takes: ffff3ec4036ce098 (_xmit_ETHER#2){+.?.}-{3:3}, at: netif_freeze_queues+0x5c/0xc0 {IN-SOFTIRQ-W} state was registered at: _raw_spin_lock+0x5c/0xc0 sch_direct_xmit+0x148/0x37c __dev_queue_xmit+0x528/0x111c ip6_finish_output2+0x5ec/0xb7c ip6_finish_output+0x240/0x3f0 ip6_output+0x78/0x360 ndisc_send_skb+0x33c/0x85c ndisc_send_rs+0x54/0x12c addrconf_rs_timer+0x154/0x260 call_timer_fn+0xb8/0x3a0 __run_timers.part.0+0x214/0x26c run_timer_softirq+0x3c/0x74 __do_softirq+0x14c/0x5d8 ____do_softirq+0x10/0x20 call_on_irq_stack+0x2c/0x5c do_softirq_own_stack+0x1c/0x30 __irq_exit_rcu+0x168/0x1a0 irq_exit_rcu+0x10/0x40 el1_interrupt+0x38/0x64 irq event stamp: 7825 hardirqs last enabled at (7825): [<ffffdf1f7200cae4>] exit_to_kernel_mode+0x34/0x130 hardirqs last disabled at (7823): [<ffffdf1f708105f0>] __do_softirq+0x550/0x5d8 softirqs last enabled at (7824): [<ffffdf1f7081050c>] __do_softirq+0x46c/0x5d8 softirqs last disabled at (7811): [<ffffdf1f708166e0>] ____do_softirq+0x10/0x20 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(_xmit_ETHER#2); <Interrupt> lock(_xmit_ETHER#2); *** DEADLOCK *** 3 locks held by kworker/1:3/179: #0: ffff3ec400004748 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x1f4/0x6c0 #1: ffff80000a0bbdc8 ((work_completion)(&priv->tx_onestep_tstamp)){+.+.}-{0:0}, at: process_one_work+0x1f4/0x6c0 #2: ffff3ec4036cd438 (&dev->tx_global_lock){+.+.}-{3:3}, at: netif_tx_lock+0x1c/0x34 Workqueue: events enetc_tx_onestep_tstamp Call trace: print_usage_bug.part.0+0x208/0x22c mark_lock+0x7f0/0x8b0 __lock_acquire+0x7c4/0x1ce0 lock_acquire.part.0+0xe0/0x220 lock_acquire+0x68/0x84 _raw_spin_lock+0x5c/0xc0 netif_freeze_queues+0x5c/0xc0 netif_tx_lock+0x24/0x34 enetc_tx_onestep_tstamp+0x20/0x100 process_one_work+0x28c/0x6c0 worker_thread+0x74/0x450 kthread+0x118/0x11c but I'll say it anyway: the enetc_tx_onestep_tstamp() work item runs in process context, therefore with softirqs enabled (i.o.w., it can be interrupted by a softirq). If we hold the netif_tx_lock() when there is an interrupt, and the NET_TX softirq then gets scheduled, this will take the netif_tx_lock() a second time and deadlock the kernel. To solve this, use netif_tx_lock_bh(), which blocks softirqs from running. Fixes: 7294380 ("enetc: support PTP Sync packet one-step timestamping") Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Reviewed-by: Alexander Duyck <alexanderduyck@fb.com> Link: https://lore.kernel.org/r/20230112105440.1786799-1-vladimir.oltean@nxp.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit 3c938cc ] In case of PREEMPT_RT, there is a raw_spinlock -> spinlock dependency as the lockdep report shows. __irq_set_handler irq_get_desc_buslock __irq_get_desc_lock raw_spin_lock_irqsave(&desc->lock, *flags); // raw spinlock get here __irq_do_set_handler mask_ack_irq dwapb_irq_ack spin_lock_irqsave(&gc->bgpio_lock, flags); // sleep able spinlock irq_put_desc_busunlock Replace with a raw lock to avoid BUGs. This lock is only used to access registers, and It's safe to replace with the raw lock without bad influence. [ 15.090359][ T1] ============================= [ 15.090365][ T1] [ BUG: Invalid wait context ] [ 15.090373][ T1] 5.10.59-rt52-00983-g186a6841c682-dirty #3 Not tainted [ 15.090386][ T1] ----------------------------- [ 15.090392][ T1] swapper/0/1 is trying to lock: [ 15.090402][ T1] 70ff00018507c188 (&gc->bgpio_lock){....}-{3:3}, at: _raw_spin_lock_irqsave+0x1c/0x28 [ 15.090470][ T1] other info that might help us debug this: [ 15.090477][ T1] context-{5:5} [ 15.090485][ T1] 3 locks held by swapper/0/1: [ 15.090497][ T1] #0: c2ff0001816de1a0 (&dev->mutex){....}-{4:4}, at: __device_driver_lock+0x98/0x104 [ 15.090553][ T1] #1: ffff90001485b4b8 (irq_domain_mutex){+.+.}-{4:4}, at: irq_domain_associate+0xbc/0x6d4 [ 15.090606][ T1] #2: 4bff000185d7a8e0 (lock_class){....}-{2:2}, at: _raw_spin_lock_irqsave+0x1c/0x28 [ 15.090654][ T1] stack backtrace: [ 15.090661][ T1] CPU: 4 PID: 1 Comm: swapper/0 Not tainted 5.10.59-rt52-00983-g186a6841c682-dirty #3 [ 15.090682][ T1] Hardware name: Horizon Robotics Journey 5 DVB (DT) [ 15.090692][ T1] Call trace: ...... [ 15.090811][ T1] _raw_spin_lock_irqsave+0x1c/0x28 [ 15.090828][ T1] dwapb_irq_ack+0xb4/0x300 [ 15.090846][ T1] __irq_do_set_handler+0x494/0xb2c [ 15.090864][ T1] __irq_set_handler+0x74/0x114 [ 15.090881][ T1] irq_set_chip_and_handler_name+0x44/0x58 [ 15.090900][ T1] gpiochip_irq_map+0x210/0x644 Signed-off-by: Schspa Shi <schspa@gmail.com> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Acked-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Doug Berger <opendmb@gmail.com> Acked-by: Serge Semin <fancer.lancer@gmail.com> Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl> Stable-dep-of: e546427 ("gpio: mxc: Protect GPIO irqchip RMW with bgpio spinlock") Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit f3dc1b3 ] The first time dma_chan_get() is called for a channel the channel client_count is incorrectly incremented twice for public channels, first in balance_ref_count(), and again prior to returning. This results in an incorrect client count which will lead to the channel resources not being freed when they should be. A simple test of repeated module load and unload of async_tx on a Dell Power Edge R7425 also shows this resulting in a kref underflow warning. [ 124.329662] async_tx: api initialized (async) [ 129.000627] async_tx: api initialized (async) [ 130.047839] ------------[ cut here ]------------ [ 130.052472] refcount_t: underflow; use-after-free. [ 130.057279] WARNING: CPU: 3 PID: 19364 at lib/refcount.c:28 refcount_warn_saturate+0xba/0x110 [ 130.065811] Modules linked in: async_tx(-) rfkill intel_rapl_msr intel_rapl_common amd64_edac edac_mce_amd ipmi_ssif kvm_amd dcdbas kvm mgag200 drm_shmem_helper acpi_ipmi irqbypass drm_kms_helper ipmi_si syscopyarea sysfillrect rapl pcspkr ipmi_devintf sysimgblt fb_sys_fops k10temp i2c_piix4 ipmi_msghandler acpi_power_meter acpi_cpufreq vfat fat drm fuse xfs libcrc32c sd_mod t10_pi sg ahci crct10dif_pclmul libahci crc32_pclmul crc32c_intel ghash_clmulni_intel igb megaraid_sas i40e libata i2c_algo_bit ccp sp5100_tco dca dm_mirror dm_region_hash dm_log dm_mod [last unloaded: async_tx] [ 130.117361] CPU: 3 PID: 19364 Comm: modprobe Kdump: loaded Not tainted 5.14.0-185.el9.x86_64 #1 [ 130.126091] Hardware name: Dell Inc. PowerEdge R7425/02MJ3T, BIOS 1.18.0 01/17/2022 [ 130.133806] RIP: 0010:refcount_warn_saturate+0xba/0x110 [ 130.139041] Code: 01 01 e8 6d bd 55 00 0f 0b e9 72 9d 8a 00 80 3d 26 18 9c 01 00 75 85 48 c7 c7 f8 a3 03 9d c6 05 16 18 9c 01 01 e8 4a bd 55 00 <0f> 0b e9 4f 9d 8a 00 80 3d 01 18 9c 01 00 0f 85 5e ff ff ff 48 c7 [ 130.157807] RSP: 0018:ffffbf98898afe68 EFLAGS: 00010286 [ 130.163036] RAX: 0000000000000000 RBX: ffff9da06028e598 RCX: 0000000000000000 [ 130.170172] RDX: ffff9daf9de26480 RSI: ffff9daf9de198a0 RDI: ffff9daf9de198a0 [ 130.177316] RBP: ffff9da7cddf3970 R08: 0000000000000000 R09: 00000000ffff7fff [ 130.184459] R10: ffffbf98898afd00 R11: ffffffff9d9e8c28 R12: ffff9da7cddf1970 [ 130.191596] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 130.198739] FS: 00007f646435c740(0000) GS:ffff9daf9de00000(0000) knlGS:0000000000000000 [ 130.206832] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 130.212586] CR2: 00007f6463b214f0 CR3: 00000008ab98c000 CR4: 00000000003506e0 [ 130.219729] Call Trace: [ 130.222192] <TASK> [ 130.224305] dma_chan_put+0x10d/0x110 [ 130.227988] dmaengine_put+0x7a/0xa0 [ 130.231575] __do_sys_delete_module.constprop.0+0x178/0x280 [ 130.237157] ? syscall_trace_enter.constprop.0+0x145/0x1d0 [ 130.242652] do_syscall_64+0x5c/0x90 [ 130.246240] ? exc_page_fault+0x62/0x150 [ 130.250178] entry_SYSCALL_64_after_hwframe+0x63/0xcd [ 130.255243] RIP: 0033:0x7f6463a3f5ab [ 130.258830] Code: 73 01 c3 48 8b 0d 75 a8 1b 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa b8 b0 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 45 a8 1b 00 f7 d8 64 89 01 48 [ 130.277591] RSP: 002b:00007fff22f972c8 EFLAGS: 00000206 ORIG_RAX: 00000000000000b0 [ 130.285164] RAX: ffffffffffffffda RBX: 000055b6786edd40 RCX: 00007f6463a3f5ab [ 130.292303] RDX: 0000000000000000 RSI: 0000000000000800 RDI: 000055b6786edda8 [ 130.299443] RBP: 000055b6786edd40 R08: 0000000000000000 R09: 0000000000000000 [ 130.306584] R10: 00007f6463b9eac0 R11: 0000000000000206 R12: 000055b6786edda8 [ 130.313731] R13: 0000000000000000 R14: 000055b6786edda8 R15: 00007fff22f995f8 [ 130.320875] </TASK> [ 130.323081] ---[ end trace eff7156d56b5cf25 ]--- cat /sys/class/dma/dma0chan*/in_use would get the wrong result. 2 2 2 Fixes: d2f4f99 ("dmaengine: Rework dma_chan_get") Signed-off-by: Koba Ko <koba.ko@canonical.com> Reviewed-by: Jie Hai <haijie1@huawei.com> Test-by: Jie Hai <haijie1@huawei.com> Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com> Reviewed-by: Dave Jiang <dave.jiang@intel.com> Tested-by: Joel Savitz <jsavitz@redhat.com> Link: https://lore.kernel.org/r/20221201030050.978595-1-koba.ko@canonical.com Signed-off-by: Vinod Koul <vkoul@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit 55ba18d ] The commit 4af1b64 ("octeontx2-pf: Fix lmtst ID used in aura free") uses the get/put_cpu() to protect the usage of percpu pointer in ->aura_freeptr() callback, but it also unnecessarily disable the preemption for the blockable memory allocation. The commit 87b93b6 ("octeontx2-pf: Avoid use of GFP_KERNEL in atomic context") tried to fix these sleep inside atomic warnings. But it only fix the one for the non-rt kernel. For the rt kernel, we still get the similar warnings like below. BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:46 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 1, name: swapper/0 preempt_count: 1, expected: 0 RCU nest depth: 0, expected: 0 3 locks held by swapper/0/1: #0: ffff800009fc5fe8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock+0x24/0x30 #1: ffff000100c276c0 (&mbox->lock){+.+.}-{3:3}, at: otx2_init_hw_resources+0x8c/0x3a4 #2: ffffffbfef6537e0 (&cpu_rcache->lock){+.+.}-{2:2}, at: alloc_iova_fast+0x1ac/0x2ac Preemption disabled at: [<ffff800008b1908c>] otx2_rq_aura_pool_init+0x14c/0x284 CPU: 20 PID: 1 Comm: swapper/0 Tainted: G W 6.2.0-rc3-rt1-yocto-preempt-rt #1 Hardware name: Marvell OcteonTX CN96XX board (DT) Call trace: dump_backtrace.part.0+0xe8/0xf4 show_stack+0x20/0x30 dump_stack_lvl+0x9c/0xd8 dump_stack+0x18/0x34 __might_resched+0x188/0x224 rt_spin_lock+0x64/0x110 alloc_iova_fast+0x1ac/0x2ac iommu_dma_alloc_iova+0xd4/0x110 __iommu_dma_map+0x80/0x144 iommu_dma_map_page+0xe8/0x260 dma_map_page_attrs+0xb4/0xc0 __otx2_alloc_rbuf+0x90/0x150 otx2_rq_aura_pool_init+0x1c8/0x284 otx2_init_hw_resources+0xe4/0x3a4 otx2_open+0xf0/0x610 __dev_open+0x104/0x224 __dev_change_flags+0x1e4/0x274 dev_change_flags+0x2c/0x7c ic_open_devs+0x124/0x2f8 ip_auto_config+0x180/0x42c do_one_initcall+0x90/0x4dc do_basic_setup+0x10c/0x14c kernel_init_freeable+0x10c/0x13c kernel_init+0x2c/0x140 ret_from_fork+0x10/0x20 Of course, we can shuffle the get/put_cpu() to only wrap the invocation of ->aura_freeptr() as what commit 87b93b6 does. But there are only two ->aura_freeptr() callbacks, otx2_aura_freeptr() and cn10k_aura_freeptr(). There is no usage of perpcu variable in the otx2_aura_freeptr() at all, so the get/put_cpu() seems redundant to it. We can move the get/put_cpu() into the corresponding callback which really has the percpu variable usage and avoid the sprinkling of get/put_cpu() in several places. Fixes: 4af1b64 ("octeontx2-pf: Fix lmtst ID used in aura free") Signed-off-by: Kevin Hao <haokexin@gmail.com> Link: https://lore.kernel.org/r/20230118071300.3271125-1-haokexin@gmail.com Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit ba81043 ] There is a lock inversion and rwsem read-lock recursion in the devfreq target callback which can lead to deadlocks. Specifically, ufshcd_devfreq_scale() already holds a clk_scaling_lock read lock when toggling the write booster, which involves taking the dev_cmd mutex before taking another clk_scaling_lock read lock. This can lead to a deadlock if another thread: 1) tries to acquire the dev_cmd and clk_scaling locks in the correct order, or 2) takes a clk_scaling write lock before the attempt to take the clk_scaling read lock a second time. Fix this by dropping the clk_scaling_lock before toggling the write booster as was done before commit 0e9d4ca ("scsi: ufs: Protect some contexts from unexpected clock scaling"). While the devfreq callbacks are already serialised, add a second serialising mutex to handle the unlikely case where a callback triggered through the devfreq sysfs interface is racing with a request to disable clock scaling through the UFS controller 'clkscale_enable' sysfs attribute. This could otherwise lead to the write booster being left disabled after having disabled clock scaling. Also take the new mutex in ufshcd_clk_scaling_allow() to make sure that any pending write booster update has completed on return. Note that this currently only affects Qualcomm platforms since commit 87bd050 ("scsi: ufs: core: Allow host driver to disable wb toggling during clock scaling"). The lock inversion (i.e. 1 above) was reported by lockdep as: ====================================================== WARNING: possible circular locking dependency detected 6.1.0-next-20221216 torvalds#211 Not tainted ------------------------------------------------------ kworker/u16:2/71 is trying to acquire lock: ffff076280ba98a0 (&hba->dev_cmd.lock){+.+.}-{3:3}, at: ufshcd_query_flag+0x50/0x1c0 but task is already holding lock: ffff076280ba9cf0 (&hba->clk_scaling_lock){++++}-{3:3}, at: ufshcd_devfreq_scale+0x2b8/0x380 which lock already depends on the new lock. [ +0.011606] the existing dependency chain (in reverse order) is: -> #1 (&hba->clk_scaling_lock){++++}-{3:3}: lock_acquire+0x68/0x90 down_read+0x58/0x80 ufshcd_exec_dev_cmd+0x70/0x2c0 ufshcd_verify_dev_init+0x68/0x170 ufshcd_probe_hba+0x398/0x1180 ufshcd_async_scan+0x30/0x320 async_run_entry_fn+0x34/0x150 process_one_work+0x288/0x6c0 worker_thread+0x74/0x450 kthread+0x118/0x120 ret_from_fork+0x10/0x20 -> #0 (&hba->dev_cmd.lock){+.+.}-{3:3}: __lock_acquire+0x12a0/0x2240 lock_acquire.part.0+0xcc/0x220 lock_acquire+0x68/0x90 __mutex_lock+0x98/0x430 mutex_lock_nested+0x2c/0x40 ufshcd_query_flag+0x50/0x1c0 ufshcd_query_flag_retry+0x64/0x100 ufshcd_wb_toggle+0x5c/0x120 ufshcd_devfreq_scale+0x2c4/0x380 ufshcd_devfreq_target+0xf4/0x230 devfreq_set_target+0x84/0x2f0 devfreq_update_target+0xc4/0xf0 devfreq_monitor+0x38/0x1f0 process_one_work+0x288/0x6c0 worker_thread+0x74/0x450 kthread+0x118/0x120 ret_from_fork+0x10/0x20 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&hba->clk_scaling_lock); lock(&hba->dev_cmd.lock); lock(&hba->clk_scaling_lock); lock(&hba->dev_cmd.lock); *** DEADLOCK *** Fixes: 0e9d4ca ("scsi: ufs: Protect some contexts from unexpected clock scaling") Cc: stable@vger.kernel.org # 5.12 Cc: Can Guo <quic_cang@quicinc.com> Tested-by: Andrew Halaney <ahalaney@redhat.com> Signed-off-by: Johan Hovold <johan+linaro@kernel.org> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Link: https://lore.kernel.org/r/20230116161201.16923-1-johan+linaro@kernel.org Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit ca02549 ] Set kprobe at 'jalr 1140(ra)' of vfs_write results in the following crash: [ 32.092235] Unable to handle kernel access to user memory without uaccess routines at virtual address 00aaaaaad77b1170 [ 32.093115] Oops [#1] [ 32.093251] Modules linked in: [ 32.093626] CPU: 0 PID: 135 Comm: ftracetest Not tainted 6.2.0-rc2-00013-gb0aa5e5df0cb-dirty torvalds#16 [ 32.093985] Hardware name: riscv-virtio,qemu (DT) [ 32.094280] epc : ksys_read+0x88/0xd6 [ 32.094855] ra : ksys_read+0xc0/0xd6 [ 32.095016] epc : ffffffff801cda80 ra : ffffffff801cdab8 sp : ff20000000d7bdc0 [ 32.095227] gp : ffffffff80f14000 tp : ff60000080f9cb40 t0 : ffffffff80f13e80 [ 32.095500] t1 : ffffffff8000c29c t2 : ffffffff800dbc54 s0 : ff20000000d7be60 [ 32.095716] s1 : 0000000000000000 a0 : ffffffff805a64ae a1 : ffffffff80a83708 [ 32.095921] a2 : ffffffff80f160a0 a3 : 0000000000000000 a4 : f229b0afdb165300 [ 32.096171] a5 : f229b0afdb165300 a6 : ffffffff80eeebd0 a7 : 00000000000003ff [ 32.096411] s2 : ff6000007ff76800 s3 : fffffffffffffff7 s4 : 00aaaaaad77b1170 [ 32.096638] s5 : ffffffff80f160a0 s6 : ff6000007ff76800 s7 : 0000000000000030 [ 32.096865] s8 : 00ffffffc3d97be0 s9 : 0000000000000007 s10: 00aaaaaad77c9410 [ 32.097092] s11: 0000000000000000 t3 : ffffffff80f13e48 t4 : ffffffff8000c29c [ 32.097317] t5 : ffffffff8000c29c t6 : ffffffff800dbc54 [ 32.097505] status: 0000000200000120 badaddr: 00aaaaaad77b1170 cause: 000000000000000d [ 32.098011] [<ffffffff801cdb72>] ksys_write+0x6c/0xd6 [ 32.098222] [<ffffffff801cdc06>] sys_write+0x2a/0x38 [ 32.098405] [<ffffffff80003c76>] ret_from_syscall+0x0/0x2 Since the rs1 and rd might be the same one, such as 'jalr 1140(ra)', hence it requires obtaining the target address from rs1 followed by updating rd. Fixes: c22b0bc ("riscv: Add kprobes supported") Signed-off-by: Liao Chang <liaochang1@huawei.com> Reviewed-by: Guo Ren <guoren@kernel.org> Link: https://lore.kernel.org/r/20230116064342.2092136-1-liaochang1@huawei.com [Palmer: Pick Guo's cleanup] Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com> Signed-off-by: Sasha Levin <sashal@kernel.org>

Thread #1: [122554.641906][ T92] f2fs_getxattr+0xd4/0x5fc -> waiting for f2fs_down_read(&F2FS_I(inode)->i_xattr_sem); [122554.641927][ T92] __f2fs_get_acl+0x50/0x284 [122554.641948][ T92] f2fs_init_acl+0x84/0x54c [122554.641969][ T92] f2fs_init_inode_metadata+0x460/0x5f0 [122554.641990][ T92] f2fs_add_inline_entry+0x11c/0x350 -> Locked dir->inode_page by f2fs_get_node_page() [122554.642009][ T92] f2fs_do_add_link+0x100/0x1e4 [122554.642025][ T92] f2fs_create+0xf4/0x22c [122554.642047][ T92] vfs_create+0x130/0x1f4 Thread #2: [123996.386358][ T92] __get_node_page+0x8c/0x504 -> waiting for dir->inode_page lock [123996.386383][ T92] read_all_xattrs+0x11c/0x1f4 [123996.386405][ T92] __f2fs_setxattr+0xcc/0x528 [123996.386424][ T92] f2fs_setxattr+0x158/0x1f4 -> f2fs_down_write(&F2FS_I(inode)->i_xattr_sem); [123996.386443][ T92] __f2fs_set_acl+0x328/0x430 [123996.386618][ T92] f2fs_set_acl+0x38/0x50 [123996.386642][ T92] posix_acl_chmod+0xc8/0x1c8 [123996.386669][ T92] f2fs_setattr+0x5e0/0x6bc [123996.386689][ T92] notify_change+0x4d8/0x580 [123996.386717][ T92] chmod_common+0xd8/0x184 [123996.386748][ T92] do_fchmodat+0x60/0x124 [123996.386766][ T92] __arm64_sys_fchmodat+0x28/0x3c Bug: 280545073 Fixes: 27161f1 "f2fs: avoid race in between read xattr & write xattr" Cc: <stable@vger.kernel.org> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> (cherry picked from commit 82d8a4f642421ece594542e1fabc689dcb094b1a) Change-Id: Iec383216e1887e11c69374d28e4ecdedda133919

As previously noted in commit 66e4f4a ("rtc: cmos: Use spin_lock_irqsave() in cmos_interrupt()"): <4>[ 254.192378] WARNING: inconsistent lock state <4>[ 254.192384] 5.12.0-rc1-CI-CI_DRM_9834+ #1 Not tainted <4>[ 254.192396] -------------------------------- <4>[ 254.192400] inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage. <4>[ 254.192409] rtcwake/5309 [HC0[0]:SC0[0]:HE1:SE1] takes: <4>[ 254.192429] ffffffff8263c5f8 (rtc_lock){?...}-{2:2}, at: cmos_interrupt+0x18/0x100 <4>[ 254.192481] {IN-HARDIRQ-W} state was registered at: <4>[ 254.192488] lock_acquire+0xd1/0x3d0 <4>[ 254.192504] _raw_spin_lock+0x2a/0x40 <4>[ 254.192519] cmos_interrupt+0x18/0x100 <4>[ 254.192536] rtc_handler+0x1f/0xc0 <4>[ 254.192553] acpi_ev_fixed_event_detect+0x109/0x13c <4>[ 254.192574] acpi_ev_sci_xrupt_handler+0xb/0x28 <4>[ 254.192596] acpi_irq+0x13/0x30 <4>[ 254.192620] __handle_irq_event_percpu+0x43/0x2c0 <4>[ 254.192641] handle_irq_event_percpu+0x2b/0x70 <4>[ 254.192661] handle_irq_event+0x2f/0x50 <4>[ 254.192680] handle_fasteoi_irq+0x9e/0x150 <4>[ 254.192693] __common_interrupt+0x76/0x140 <4>[ 254.192715] common_interrupt+0x96/0xc0 <4>[ 254.192732] asm_common_interrupt+0x1e/0x40 <4>[ 254.192750] _raw_spin_unlock_irqrestore+0x38/0x60 <4>[ 254.192767] resume_irqs+0xba/0xf0 <4>[ 254.192786] dpm_resume_noirq+0x245/0x3d0 <4>[ 254.192811] suspend_devices_and_enter+0x230/0xaa0 <4>[ 254.192835] pm_suspend.cold.8+0x301/0x34a <4>[ 254.192859] state_store+0x7b/0xe0 <4>[ 254.192879] kernfs_fop_write_iter+0x11d/0x1c0 <4>[ 254.192899] new_sync_write+0x11d/0x1b0 <4>[ 254.192916] vfs_write+0x265/0x390 <4>[ 254.192933] ksys_write+0x5a/0xd0 <4>[ 254.192949] do_syscall_64+0x33/0x80 <4>[ 254.192965] entry_SYSCALL_64_after_hwframe+0x44/0xae <4>[ 254.192986] irq event stamp: 43775 <4>[ 254.192994] hardirqs last enabled at (43775): [<ffffffff81c00c42>] asm_sysvec_apic_timer_interrupt+0x12/0x20 <4>[ 254.193023] hardirqs last disabled at (43774): [<ffffffff81aa691a>] sysvec_apic_timer_interrupt+0xa/0xb0 <4>[ 254.193049] softirqs last enabled at (42548): [<ffffffff81e00342>] __do_softirq+0x342/0x48e <4>[ 254.193074] softirqs last disabled at (42543): [<ffffffff810b45fd>] irq_exit_rcu+0xad/0xd0 <4>[ 254.193101] other info that might help us debug this: <4>[ 254.193107] Possible unsafe locking scenario: <4>[ 254.193112] CPU0 <4>[ 254.193117] ---- <4>[ 254.193121] lock(rtc_lock); <4>[ 254.193137] <Interrupt> <4>[ 254.193142] lock(rtc_lock); <4>[ 254.193156] *** DEADLOCK *** <4>[ 254.193161] 6 locks held by rtcwake/5309: <4>[ 254.193174] #0: ffff888104861430 (sb_writers#5){.+.+}-{0:0}, at: ksys_write+0x5a/0xd0 <4>[ 254.193232] #1: ffff88810f823288 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0xe7/0x1c0 <4>[ 254.193282] #2: ffff888100cef3c0 (kn->active#285 <7>[ 254.192706] i915 0000:00:02.0: [drm:intel_modeset_setup_hw_state [i915]] [CRTC:51:pipe A] hw state readout: disabled <4>[ 254.193307] ){.+.+}-{0:0}, at: kernfs_fop_write_iter+0xf0/0x1c0 <4>[ 254.193333] #3: ffffffff82649fa8 (system_transition_mutex){+.+.}-{3:3}, at: pm_suspend.cold.8+0xce/0x34a <4>[ 254.193387] #4: ffffffff827a2108 (acpi_scan_lock){+.+.}-{3:3}, at: acpi_suspend_begin+0x47/0x70 <4>[ 254.193433] #5: ffff8881019ea178 (&dev->mutex){....}-{3:3}, at: device_resume+0x68/0x1e0 <4>[ 254.193485] stack backtrace: <4>[ 254.193492] CPU: 1 PID: 5309 Comm: rtcwake Not tainted 5.12.0-rc1-CI-CI_DRM_9834+ #1 <4>[ 254.193514] Hardware name: Google Soraka/Soraka, BIOS MrChromebox-4.10 08/25/2019 <4>[ 254.193524] Call Trace: <4>[ 254.193536] dump_stack+0x7f/0xad <4>[ 254.193567] mark_lock.part.47+0x8ca/0xce0 <4>[ 254.193604] __lock_acquire+0x39b/0x2590 <4>[ 254.193626] ? asm_sysvec_apic_timer_interrupt+0x12/0x20 <4>[ 254.193660] lock_acquire+0xd1/0x3d0 <4>[ 254.193677] ? cmos_interrupt+0x18/0x100 <4>[ 254.193716] _raw_spin_lock+0x2a/0x40 <4>[ 254.193735] ? cmos_interrupt+0x18/0x100 <4>[ 254.193758] cmos_interrupt+0x18/0x100 <4>[ 254.193785] cmos_resume+0x2ac/0x2d0 <4>[ 254.193813] ? acpi_pm_set_device_wakeup+0x1f/0x110 <4>[ 254.193842] ? pnp_bus_suspend+0x10/0x10 <4>[ 254.193864] pnp_bus_resume+0x5e/0x90 <4>[ 254.193885] dpm_run_callback+0x5f/0x240 <4>[ 254.193914] device_resume+0xb2/0x1e0 <4>[ 254.193942] ? pm_dev_err+0x25/0x25 <4>[ 254.193974] dpm_resume+0xea/0x3f0 <4>[ 254.194005] dpm_resume_end+0x8/0x10 <4>[ 254.194030] suspend_devices_and_enter+0x29b/0xaa0 <4>[ 254.194066] pm_suspend.cold.8+0x301/0x34a <4>[ 254.194094] state_store+0x7b/0xe0 <4>[ 254.194124] kernfs_fop_write_iter+0x11d/0x1c0 <4>[ 254.194151] new_sync_write+0x11d/0x1b0 <4>[ 254.194183] vfs_write+0x265/0x390 <4>[ 254.194207] ksys_write+0x5a/0xd0 <4>[ 254.194232] do_syscall_64+0x33/0x80 <4>[ 254.194251] entry_SYSCALL_64_after_hwframe+0x44/0xae <4>[ 254.194274] RIP: 0033:0x7f07d79691e7 <4>[ 254.194293] Code: 64 89 02 48 c7 c0 ff ff ff ff eb bb 0f 1f 80 00 00 00 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 48 89 54 24 18 48 89 74 24 <4>[ 254.194312] RSP: 002b:00007ffd9cc2c768 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 <4>[ 254.194337] RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007f07d79691e7 <4>[ 254.194352] RDX: 0000000000000004 RSI: 0000556ebfc63590 RDI: 000000000000000b <4>[ 254.194366] RBP: 0000556ebfc63590 R08: 0000000000000000 R09: 0000000000000004 <4>[ 254.194379] R10: 0000556ebf0ec2a6 R11: 0000000000000246 R12: 0000000000000004 which breaks S3-resume on fi-kbl-soraka presumably as that's slow enough to trigger the alarm during the suspend. Fixes: 6950d04 ("rtc: cmos: Replace spin_lock_irqsave with spin_lock in hard IRQ") References: 66e4f4a ("rtc: cmos: Use spin_lock_irqsave() in cmos_interrupt()"): Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Xiaofei Tan <tanxiaofei@huawei.com> Cc: Alexandre Belloni <alexandre.belloni@bootlin.com> Cc: Alessandro Zummo <a.zummo@towertech.it> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210305122140.28774-1-chris@chris-wilson.co.uk

When passing 'phys' in the devicetree to describe the USB PHY phandle (which is the recommended way according to Documentation/devicetree/bindings/usb/ci-hdrc-usb2.txt) the following NULL pointer dereference is observed on i.MX7 and i.MX8MM: [ 1.489344] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000098 [ 1.498170] Mem abort info: [ 1.500966] ESR = 0x96000044 [ 1.504030] EC = 0x25: DABT (current EL), IL = 32 bits [ 1.509356] SET = 0, FnV = 0 [ 1.512416] EA = 0, S1PTW = 0 [ 1.515569] FSC = 0x04: level 0 translation fault [ 1.520458] Data abort info: [ 1.523349] ISV = 0, ISS = 0x00000044 [ 1.527196] CM = 0, WnR = 1 [ 1.530176] [0000000000000098] user address but active_mm is swapper [ 1.536544] Internal error: Oops: 96000044 [#1] PREEMPT SMP [ 1.542125] Modules linked in: [ 1.545190] CPU: 3 PID: 7 Comm: kworker/u8:0 Not tainted 5.14.0-dirty #3 [ 1.551901] Hardware name: Kontron i.MX8MM N801X S (DT) [ 1.557133] Workqueue: events_unbound deferred_probe_work_func [ 1.562984] pstate: 80000005 (Nzcv daif -PAN -UAO -TCO BTYPE=--) [ 1.568998] pc : imx7d_charger_detection+0x3f0/0x510 [ 1.573973] lr : imx7d_charger_detection+0x22c/0x510 This happens because the charger functions check for the phy presence inside the imx_usbmisc_data structure (data->usb_phy), but the chipidea core populates the usb_phy passed via 'phys' inside 'struct ci_hdrc' (ci->usb_phy) instead. This causes the NULL pointer dereference inside imx7d_charger_detection(). Fix it by also searching for 'phys' in case 'fsl,usbphy' is not found. Tested on a imx7s-warp board. Cc: stable@vger.kernel.org Fixes: 746f316 ("usb: chipidea: introduce imx7d USB charger detection") Reported-by: Heiko Thiery <heiko.thiery@gmail.com> Signed-off-by: Fabio Estevam <festevam@gmail.com> Tested-by: Frieder Schrempf <frieder.schrempf@kontron.de> Reviewed-by: Frieder Schrempf <frieder.schrempf@kontron.de> Link: https://lore.kernel.org/r/20210921113754.767631-1-festevam@gmail.com Signed-off-by: Peter Chen <peter.chen@kernel.org>

btrfs_can_activate_zone() can be called with the device_list_mutex already held, which will lead to a deadlock: insert_dev_extents() // Takes device_list_mutex `-> insert_dev_extent() `-> btrfs_insert_empty_item() `-> btrfs_insert_empty_items() `-> btrfs_search_slot() `-> btrfs_cow_block() `-> __btrfs_cow_block() `-> btrfs_alloc_tree_block() `-> btrfs_reserve_extent() `-> find_free_extent() `-> find_free_extent_update_loop() `-> can_allocate_chunk() `-> btrfs_can_activate_zone() // Takes device_list_mutex again As we're only traversing the list for reads we can switch from the device_list_mutex to an RCU traversal of the list. [15.166572] WARNING: possible recursive locking detected [15.167117] 5.17.0-rc6-dennis torvalds#79 Not tainted [15.167487] -------------------------------------------- [15.167733] kworker/u8:3/146 is trying to acquire lock: [15.167733] ffff888102962ee0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: find_free_extent+0x15a/0x14f0 [btrfs] [15.167733] [15.167733] but task is already holding lock: [15.167733] ffff888102962ee0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: btrfs_create_pending_block_groups+0x20a/0x560 [btrfs] [15.167733] [15.167733] other info that might help us debug this: [15.167733] Possible unsafe locking scenario: [15.167733] [15.171834] CPU0 [15.171834] ---- [15.171834] lock(&fs_devs->device_list_mutex); [15.171834] lock(&fs_devs->device_list_mutex); [15.171834] [15.171834] *** DEADLOCK *** [15.171834] [15.171834] May be due to missing lock nesting notation [15.171834] [15.171834] 5 locks held by kworker/u8:3/146: [15.171834] #0: ffff888100050938 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x1c3/0x5a0 [15.171834] #1: ffffc9000067be80 ((work_completion)(&fs_info->async_data_reclaim_work)){+.+.}-{0:0}, at: process_one_work+0x1c3/0x5a0 [15.176244] #2: ffff88810521e620 (sb_internal){.+.+}-{0:0}, at: flush_space+0x335/0x600 [btrfs] [15.176244] #3: ffff888102962ee0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: btrfs_create_pending_block_groups+0x20a/0x560 [btrfs] [15.176244] #4: ffff8881152e4b78 (btrfs-dev-00){++++}-{3:3}, at: __btrfs_tree_lock+0x27/0x130 [btrfs] [15.179641] [15.179641] stack backtrace: [15.179641] CPU: 1 PID: 146 Comm: kworker/u8:3 Not tainted 5.17.0-rc6-dennis torvalds#79 [15.179641] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1.fc35 04/01/2014 [15.179641] Workqueue: events_unbound btrfs_async_reclaim_data_space [btrfs] [15.179641] Call Trace: [15.179641] <TASK> [15.179641] dump_stack_lvl+0x45/0x59 [15.179641] __lock_acquire.cold+0x217/0x2b2 [15.179641] lock_acquire+0xbf/0x2b0 [15.183838] ? find_free_extent+0x15a/0x14f0 [btrfs] [15.183838] __mutex_lock+0x8e/0x970 [15.183838] ? find_free_extent+0x15a/0x14f0 [btrfs] [15.183838] ? find_free_extent+0x15a/0x14f0 [btrfs] [15.183838] ? lock_is_held_type+0xd7/0x130 [15.183838] ? find_free_extent+0x15a/0x14f0 [btrfs] [15.183838] find_free_extent+0x15a/0x14f0 [btrfs] [15.183838] ? _raw_spin_unlock+0x24/0x40 [15.183838] ? btrfs_get_alloc_profile+0x106/0x230 [btrfs] [15.187601] btrfs_reserve_extent+0x131/0x260 [btrfs] [15.187601] btrfs_alloc_tree_block+0xb5/0x3b0 [btrfs] [15.187601] __btrfs_cow_block+0x138/0x600 [btrfs] [15.187601] btrfs_cow_block+0x10f/0x230 [btrfs] [15.187601] btrfs_search_slot+0x55f/0xbc0 [btrfs] [15.187601] ? lock_is_held_type+0xd7/0x130 [15.187601] btrfs_insert_empty_items+0x2d/0x60 [btrfs] [15.187601] btrfs_create_pending_block_groups+0x2b3/0x560 [btrfs] [15.187601] __btrfs_end_transaction+0x36/0x2a0 [btrfs] [15.192037] flush_space+0x374/0x600 [btrfs] [15.192037] ? find_held_lock+0x2b/0x80 [15.192037] ? btrfs_async_reclaim_data_space+0x49/0x180 [btrfs] [15.192037] ? lock_release+0x131/0x2b0 [15.192037] btrfs_async_reclaim_data_space+0x70/0x180 [btrfs] [15.192037] process_one_work+0x24c/0x5a0 [15.192037] worker_thread+0x4a/0x3d0 Fixes: a85f05e ("btrfs: zoned: avoid chunk allocation if active block group has enough space") CC: stable@vger.kernel.org # 5.16+ Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>

There is a kernel panic caused by pcpu_alloc_pages() passing offlined and uninitialized node to alloc_pages_node() leading to panic by NULL dereferencing uninitialized NODE_DATA(nid). CPU2 has been hot-added BUG: unable to handle page fault for address: 0000000000001608 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] SMP PTI CPU: 0 PID: 1 Comm: systemd Tainted: G E 5.15.0-rc7+ torvalds#11 Hardware name: VMware, Inc. VMware7,1/440BX Desktop Reference Platform, BIOS VMW RIP: 0010:__alloc_pages+0x127/0x290 Code: 4c 89 f0 5b 41 5c 41 5d 41 5e 41 5f 5d c3 44 89 e0 48 8b 55 b8 c1 e8 0c 83 e0 01 88 45 d0 4c 89 c8 48 85 d2 0f 85 1a 01 00 00 <45> 3b 41 08 0f 82 10 01 00 00 48 89 45 c0 48 8b 00 44 89 e2 81 e2 RSP: 0018:ffffc900006f3bc8 EFLAGS: 00010246 RAX: 0000000000001600 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000cc2 RBP: ffffc900006f3c18 R08: 0000000000000001 R09: 0000000000001600 R10: ffffc900006f3a40 R11: ffff88813c9fffe8 R12: 0000000000000cc2 R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000cc2 FS: 00007f27ead70500(0000) GS:ffff88807ce00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000001608 CR3: 000000000582c003 CR4: 00000000001706b0 Call Trace: pcpu_alloc_pages.constprop.0+0xe4/0x1c0 pcpu_populate_chunk+0x33/0xb0 pcpu_alloc+0x4d3/0x6f0 __alloc_percpu_gfp+0xd/0x10 alloc_mem_cgroup_per_node_info+0x54/0xb0 mem_cgroup_alloc+0xed/0x2f0 mem_cgroup_css_alloc+0x33/0x2f0 css_create+0x3a/0x1f0 cgroup_apply_control_enable+0x12b/0x150 cgroup_mkdir+0xdd/0x110 kernfs_iop_mkdir+0x4f/0x80 vfs_mkdir+0x178/0x230 do_mkdirat+0xfd/0x120 __x64_sys_mkdir+0x47/0x70 ? syscall_exit_to_user_mode+0x21/0x50 do_syscall_64+0x43/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae Panic can be easily reproduced by disabling udev rule for automatic onlining hot added CPU followed by CPU with memoryless node (NUMA node with CPU only) hot add. Hot adding CPU and memoryless node does not bring the node to online state. Memoryless node will be onlined only during the onlining its CPU. Node can be in one of the following states: 1. not present.(nid == NUMA_NO_NODE) 2. present, but offline (nid > NUMA_NO_NODE, node_online(nid) == 0, NODE_DATA(nid) == NULL) 3. present and online (nid > NUMA_NO_NODE, node_online(nid) > 0, NODE_DATA(nid) != NULL) Percpu code is doing allocations for all possible CPUs. The issue happens when it serves hot added but not yet onlined CPU when its node is in 2nd state. This node is not ready to use, fallback to numa_mem_id(). Link: https://lkml.kernel.org/r/20211108202325.20304-1-amakhalov@vmware.com Signed-off-by: Alexey Makhalov <amakhalov@vmware.com> Reviewed-by: David Hildenbrand <david@redhat.com> Acked-by: Dennis Zhou <dennis@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Tejun Heo <tj@kernel.org> Cc: Christoph Lameter <cl@linux.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>

A kernel panic was observed during reading /proc/kpageflags for first few pfns allocated by pmem namespace: BUG: unable to handle page fault for address: fffffffffffffffe [ 114.495280] #PF: supervisor read access in kernel mode [ 114.495738] #PF: error_code(0x0000) - not-present page [ 114.496203] PGD 17120e067 P4D 17120e067 PUD 171210067 PMD 0 [ 114.496713] Oops: 0000 [#1] SMP PTI [ 114.497037] CPU: 9 PID: 1202 Comm: page-types Not tainted 5.3.0-rc1 #1 [ 114.497621] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.11.0-0-g63451fca13-prebuilt.qemu-project.org 04/01/2014 [ 114.498706] RIP: 0010:stable_page_flags+0x27/0x3f0 [ 114.499142] Code: 82 66 90 66 66 66 66 90 48 85 ff 0f 84 d1 03 00 00 41 54 55 48 89 fd 53 48 8b 57 08 48 8b 1f 48 8d 42 ff 83 e2 01 48 0f 44 c7 <48> 8b 00 f6 c4 02 0f 84 57 03 00 00 45 31 e4 48 8b 55 08 48 89 ef [ 114.500788] RSP: 0018:ffffa5e601a0fe60 EFLAGS: 00010202 [ 114.501373] RAX: fffffffffffffffe RBX: ffffffffffffffff RCX: 0000000000000000 [ 114.502009] RDX: 0000000000000001 RSI: 00007ffca13a7310 RDI: ffffd07489000000 [ 114.502637] RBP: ffffd07489000000 R08: 0000000000000001 R09: 0000000000000000 [ 114.503270] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000240000 [ 114.503896] R13: 0000000000080000 R14: 00007ffca13a7310 R15: ffffa5e601a0ff08 [ 114.504530] FS: 00007f0266c7f540(0000) GS:ffff962dbbac0000(0000) knlGS:0000000000000000 [ 114.505245] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 114.505754] CR2: fffffffffffffffe CR3: 000000023a204000 CR4: 00000000000006e0 [ 114.506401] Call Trace: [ 114.506660] kpageflags_read+0xb1/0x130 [ 114.507051] proc_reg_read+0x39/0x60 [ 114.507387] vfs_read+0x8a/0x140 [ 114.507686] ksys_pread64+0x61/0xa0 [ 114.508021] do_syscall_64+0x5f/0x1a0 [ 114.508372] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 114.508844] RIP: 0033:0x7f0266ba426b The reason for the panic is that stable_page_flags() which parses the page flags uses uninitialized struct pages reserved by the ZONE_DEVICE driver. Earlier approach to fix this was discussed here: https://marc.info/?l=linux-mm&m=152964770000672&w=2 This is another approach. To avoid using the uninitialized struct page, immediately return with KPF_RESERVED at the beginning of stable_page_flags() if the page is reserved by ZONE_DEVICE driver. Dan said: : The nvdimm implementation uses vmem_altmap to arrange for the 'struct : page' array to be allocated from a reservation of a pmem namespace. A : namespace in this mode contains an info-block that consumes the first : 8K of the namespace capacity, capacity designated for page mapping, : capacity for padding the start of data to optionally 4K, 2MB, or 1GB : (on x86), and then the namespace data itself. The implementation : specifies a section aligned (now sub-section aligned) address to : arch_add_memory() to establish the linear mapping to map the metadata, : and then vmem_altmap indicates to memmap_init_zone() which pfns : represent data. The implementation only specifies enough 'struct page' : capacity for pfn_to_page() to operate on the data space, not the : namespace metadata space. : : The proposal to validate ZONE_DEVICE pfns against the altmap seems the : right approach to me. Link: http://lkml.kernel.org/r/20190725023100.31141-3-t-fukasawa@vx.jp.nec.com Signed-off-by: Toshiki Fukasawa <t-fukasawa@vx.jp.nec.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Junichi Nomura <j-nomura@ce.jp.nec.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>

Patch series "mm: enforce pageblock_order < MAX_ORDER". Having pageblock_order >= MAX_ORDER seems to be able to happen in corner cases and some parts of the kernel are not prepared for it. For example, Aneesh has shown [1] that such kernels can be compiled on ppc64 with 64k base pages by setting FORCE_MAX_ZONEORDER=8, which will run into a WARN_ON_ONCE(order >= MAX_ORDER) in comapction code right during boot. We can get pageblock_order >= MAX_ORDER when the default hugetlb size is bigger than the maximum allocation granularity of the buddy, in which case we are no longer talking about huge pages but instead gigantic pages. Having pageblock_order >= MAX_ORDER can only make alloc_contig_range() of such gigantic pages more likely to succeed. Reliable use of gigantic pages either requires boot time allcoation or CMA, no need to overcomplicate some places in the kernel to optimize for corner cases that are broken in other areas of the kernel. This patch (of 2): Let's enforce pageblock_order < MAX_ORDER and simplify. Especially patch #1 can be regarded a cleanup before: [PATCH v5 0/6] Use pageblock_order for cma and alloc_contig_range alignment. [2] [1] https://lkml.kernel.org/r/87r189a2ks.fsf@linux.ibm.com [2] https://lkml.kernel.org/r/20220211164135.1803616-1-zi.yan@sent.com Link: https://lkml.kernel.org/r/20220214174132.219303-2-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Acked-by: Rob Herring <robh@kernel.org> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Frank Rowand <frowand.list@gmail.com> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Robin Murphy <robin.murphy@arm.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: John Garry via iommu <iommu@lists.linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>

ZONE_MOVABLE uses the remaining memory in each node. Its starting pfn is also aligned to MAX_ORDER_NR_PAGES. It is possible for the remaining memory in a node to be less than MAX_ORDER_NR_PAGES, meaning there is not enough room for ZONE_MOVABLE on that node. Unfortunately this condition is not checked for. This leads to zone_movable_pfn[] getting set to a pfn greater than the last pfn in a node. calculate_node_totalpages() then sets zone->present_pages to be greater than zone->spanned_pages which is invalid, as spanned_pages represents the maximum number of pages in a zone assuming no holes. Subsequently it is possible free_area_init_core() will observe a zone of size zero with present pages. In this case it will skip setting up the zone, including the initialisation of free_lists[]. However populated_zone() checks zone->present_pages to see if a zone has memory available. This is used by iterators such as walk_zones_in_node(). pagetypeinfo_showfree() uses this to walk the free_list of each zone in each node, which are assumed to be initialised due to the zone not being empty. As free_area_init_core() never initialised the free_lists[] this results in the following kernel crash when trying to read /proc/pagetypeinfo: [ 67.534914] BUG: kernel NULL pointer dereference, address: 0000000000000000 [ 67.535429] #PF: supervisor read access in kernel mode [ 67.535789] #PF: error_code(0x0000) - not-present page [ 67.536128] PGD 0 P4D 0 [ 67.536305] Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC NOPTI [ 67.536696] CPU: 0 PID: 456 Comm: cat Not tainted 5.16.0 torvalds#461 [ 67.537096] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014 [ 67.537638] RIP: 0010:pagetypeinfo_show+0x163/0x460 [ 67.537992] Code: 9e 82 e8 80 57 0e 00 49 8b 06 b9 01 00 00 00 4c 39 f0 75 16 e9 65 02 00 00 48 83 c1 01 48 81 f9 a0 86 01 00 0f 84 48 02 00 00 <48> 8b 00 4c 39 f0 75 e7 48 c7 c2 80 a2 e2 82 48 c7 c6 79 ef e3 82 [ 67.538259] RSP: 0018:ffffc90001c4bd10 EFLAGS: 00010003 [ 67.538259] RAX: 0000000000000000 RBX: ffff88801105f638 RCX: 0000000000000001 [ 67.538259] RDX: 0000000000000001 RSI: 000000000000068b RDI: ffff8880163dc68b [ 67.538259] RBP: ffffc90001c4bd90 R08: 0000000000000001 R09: ffff8880163dc67e [ 67.538259] R10: 656c6261766f6d6e R11: 6c6261766f6d6e55 R12: ffff88807ffb4a00 [ 67.538259] R13: ffff88807ffb49f8 R14: ffff88807ffb4580 R15: ffff88807ffb3000 [ 67.538259] FS: 00007f9c83eff5c0(0000) GS:ffff88807dc00000(0000) knlGS:0000000000000000 [ 67.538259] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 67.538259] CR2: 0000000000000000 CR3: 0000000013c8e000 CR4: 0000000000350ef0 [ 67.538259] Call Trace: [ 67.538259] <TASK> [ 67.538259] seq_read_iter+0x128/0x460 [ 67.538259] ? aa_file_perm+0x1af/0x5f0 [ 67.538259] proc_reg_read_iter+0x51/0x80 [ 67.538259] ? lock_is_held_type+0xea/0x140 [ 67.538259] new_sync_read+0x113/0x1a0 [ 67.538259] vfs_read+0x136/0x1d0 [ 67.538259] ksys_read+0x70/0xf0 [ 67.538259] __x64_sys_read+0x1a/0x20 [ 67.538259] do_syscall_64+0x3b/0xc0 [ 67.538259] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 67.538259] RIP: 0033:0x7f9c83e23cce [ 67.538259] Code: c0 e9 b6 fe ff ff 50 48 8d 3d 6e 13 0a 00 e8 c9 e3 01 00 66 0f 1f 84 00 00 00 00 00 64 8b 04 25 18 00 00 00 85 c0 75 14 0f 05 <48> 3d 00 f0 ff ff 77 5a c3 66 0f 1f 84 00 00 00 00 00 48 83 ec 28 [ 67.538259] RSP: 002b:00007fff116e1a08 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 [ 67.538259] RAX: ffffffffffffffda RBX: 0000000000020000 RCX: 00007f9c83e23cce [ 67.538259] RDX: 0000000000020000 RSI: 00007f9c83a2c000 RDI: 0000000000000003 [ 67.538259] RBP: 00007f9c83a2c000 R08: 00007f9c83a2b010 R09: 0000000000000000 [ 67.538259] R10: 00007f9c83f2d7d0 R11: 0000000000000246 R12: 0000000000000000 [ 67.538259] R13: 0000000000000003 R14: 0000000000020000 R15: 0000000000020000 [ 67.538259] </TASK> Fix this by checking that the aligned zone_movable_pfn[] does not exceed the end of the node, and if it does skip creating a movable zone on this node. Link: https://lkml.kernel.org/r/20220215025831.2113067-1-apopple@nvidia.com Fixes: 2a1e274 ("Create the ZONE_MOVABLE zone") Signed-off-by: Alistair Popple <apopple@nvidia.com> Acked-by: David Hildenbrand <david@redhat.com> Acked-by: Mel Gorman <mgorman@techsingularity.net> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Zi Yan <ziy@nvidia.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>

On x86, prior to ("mm: handle uninitialized numa nodes gracecully"), NUMA nodes could be allocated at three different places. - numa_register_memblks - init_cpu_to_node - init_gi_nodes All these calls happen at setup_arch, and have the following order: setup_arch ... x86_numa_init numa_init numa_register_memblks ... init_cpu_to_node init_memory_less_node alloc_node_data free_area_init_memoryless_node init_gi_nodes init_memory_less_node alloc_node_data free_area_init_memoryless_node numa_register_memblks() is only interested in those nodes which have memory, so it skips over any memoryless node it founds. Later on, when we have read ACPI's SRAT table, we call init_cpu_to_node() and init_gi_nodes(), which initialize any memoryless node we might have that have either CPU or Initiator affinity, meaning we allocate pg_data_t struct for them and we mark them as ONLINE. So far so good, but the thing is that after ("mm: handle uninitialized numa nodes gracefully"), we allocate all possible NUMA nodes in free_area_init(), meaning we have a picture like the following: setup_arch x86_numa_init numa_init numa_register_memblks <-- allocate non-memoryless node x86_init.paging.pagetable_init ... free_area_init free_area_init_memoryless <-- allocate memoryless node init_cpu_to_node alloc_node_data <-- allocate memoryless node with CPU free_area_init_memoryless_node init_gi_nodes alloc_node_data <-- allocate memoryless node with Initiator free_area_init_memoryless_node free_area_init() already allocates all possible NUMA nodes, but init_cpu_to_node() and init_gi_nodes() are clueless about that, so they go ahead and allocate a new pg_data_t struct without checking anything, meaning we end up allocating twice. It should be mad clear that this only happens in the case where memoryless NUMA node happens to have a CPU/Initiator affinity. So get rid of init_memory_less_node() and just set the node online. Note that setting the node online is needed, otherwise we choke down the chain when bringup_nonboot_cpus() ends up calling __try_online_node()->register_one_node()->... and we blow up in bus_add_device(). As can be seen here: ========== [ 0.585060] BUG: kernel NULL pointer dereference, address: 0000000000000060 [ 0.586091] #PF: supervisor read access in kernel mode [ 0.586831] #PF: error_code(0x0000) - not-present page [ 0.586930] PGD 0 P4D 0 [ 0.586930] Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC PTI [ 0.586930] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.17.0-rc4-1-default+ torvalds#45 [ 0.586930] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.0.0-prebuilt.qemu-project.org 04/4 [ 0.586930] RIP: 0010:bus_add_device+0x5a/0x140 [ 0.586930] Code: 8b 74 24 20 48 89 df e8 84 96 ff ff 85 c0 89 c5 75 38 48 8b 53 50 48 85 d2 0f 84 bb 00 004 [ 0.586930] RSP: 0000:ffffc9000022bd10 EFLAGS: 00010246 [ 0.586930] RAX: 0000000000000000 RBX: ffff888100987400 RCX: ffff8881003e4e19 [ 0.586930] RDX: ffff8881009a5e00 RSI: ffff888100987400 RDI: ffff888100987400 [ 0.586930] RBP: 0000000000000000 R08: ffff8881003e4e18 R09: ffff8881003e4c98 [ 0.586930] R10: 0000000000000000 R11: ffff888100402bc0 R12: ffffffff822ceba0 [ 0.586930] R13: 0000000000000000 R14: ffff888100987400 R15: 0000000000000000 [ 0.586930] FS: 0000000000000000(0000) GS:ffff88853fc00000(0000) knlGS:0000000000000000 [ 0.586930] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 0.586930] CR2: 0000000000000060 CR3: 000000000200a001 CR4: 00000000001706b0 [ 0.586930] Call Trace: [ 0.586930] <TASK> [ 0.586930] device_add+0x4c0/0x910 [ 0.586930] __register_one_node+0x97/0x2d0 [ 0.586930] __try_online_node+0x85/0xc0 [ 0.586930] try_online_node+0x25/0x40 [ 0.586930] cpu_up+0x4f/0x100 [ 0.586930] bringup_nonboot_cpus+0x4f/0x60 [ 0.586930] smp_init+0x26/0x79 [ 0.586930] kernel_init_freeable+0x130/0x2f1 [ 0.586930] ? rest_init+0x100/0x100 [ 0.586930] kernel_init+0x17/0x150 [ 0.586930] ? rest_init+0x100/0x100 [ 0.586930] ret_from_fork+0x22/0x30 [ 0.586930] </TASK> [ 0.586930] Modules linked in: [ 0.586930] CR2: 0000000000000060 [ 0.586930] ---[ end trace 0000000000000000 ]--- ========== The reason is simple, by the time bringup_nonboot_cpus() gets called, we did not register the node_subsys bus yet, so we crash when bus_add_device() tries to dereference bus()->p. The following shows the order of the calls: kernel_init_freeable smp_init bringup_nonboot_cpus ... bus_add_device() <- we did not register node_subsys yet do_basic_setup do_initcalls postcore_initcall(register_node_type); register_node_type subsys_system_register subsys_register bus_register <- register node_subsys bus Why setting the node online saves us then? Well, simply because __try_online_node() backs off when the node is online, meaning we do not end up calling register_one_node() in the first place. This is subtle, broken and deserves a deep analysis and thought about how to put this into shape, but for now let us have this easy fix for the leaking memory issue. Link: https://lkml.kernel.org/r/20220218224302.5282-2-osalvador@suse.de Fixes: da4490c ("mm: handle uninitialized numa nodes gracefully") Signed-off-by: Oscar Salvador <osalvador@suse.de> Acked-by: Michal Hocko <mhocko@suse.com> Cc: David Hildenbrand <david@redhat.com> Cc: Rafael Aquini <raquini@redhat.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Dennis Zhou <dennis@kernel.org> Cc: Alexey Makhalov <amakhalov@vmware.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>

…k_under_node() Patch series "drivers/base/memory: determine and store zone for single-zone memory blocks", v2. I remember talking to Michal in the past about removing test_pages_in_a_zone(), which we use for: * verifying that a memory block we intend to offline is really only managed by a single zone. We don't support offlining of memory blocks that are managed by multiple zones (e.g., multiple nodes, DMA and DMA32) * exposing that zone to user space via /sys/devices/system/memory/memory*/valid_zones Now that I identified some more cases where test_pages_in_a_zone() might go wrong, and we received an UBSAN report (see patch #3), let's get rid of this PFN walker. So instead of detecting the zone at runtime with test_pages_in_a_zone() by scanning the memmap, let's determine and remember for each memory block if it's managed by a single zone. The stored zone can then be used for the above two cases, avoiding a manual lookup using test_pages_in_a_zone(). This avoids eventually stumbling over uninitialized memmaps in corner cases, especially when ZONE_DEVICE ranges partly fall into memory block (that are responsible for managing System RAM). Handling memory onlining is easy, because we online to exactly one zone. Handling boot memory is more tricky, because we want to avoid scanning all zones of all nodes to detect possible zones that overlap with the physical memory region of interest. Fortunately, we already have code that determines the applicable nodes for a memory block, to create sysfs links -- we'll hook into that. Patch #1 is a simple cleanup I had laying around for a longer time. Patch #2 contains the main logic to remove test_pages_in_a_zone() and further details. [1] https://lkml.kernel.org/r/20220128144540.153902-1-david@redhat.com [2] https://lkml.kernel.org/r/20220203105212.30385-1-david@redhat.com This patch (of 2): Let's adjust the stale terminology, making it match unregister_memory_block_under_nodes() and do_register_memory_block_under_node(). We're dealing with memory block devices, which span 1..X memory sections. Link: https://lkml.kernel.org/r/20220210184359.235565-1-david@redhat.com Link: https://lkml.kernel.org/r/20220210184359.235565-2-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Acked-by: Oscar Salvador <osalvador@suse.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Michal Hocko <mhocko@suse.com> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Rafael Parra <rparrazo@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>

Lockdep noticed that there is chance for a deadlock if we have concurrent mmap, concurrent read, and the addition/removal of a callback. As nicely explained by Boqun: " Lockdep warned about the above sequences because rw_semaphore is a fair read-write lock, and the following can cause a deadlock: TASK 1 TASK 2 TASK 3 ====== ====== ====== down_write(mmap_lock); down_read(vmcore_cb_rwsem) down_write(vmcore_cb_rwsem); // blocked down_read(vmcore_cb_rwsem); // cannot get the lock because of the fairness down_read(mmap_lock); // blocked IOW, a reader can block another read if there is a writer queued by the second reader and the lock is fair. " To fix, convert to srcu to make this deadlock impossible. We need srcu as our callbacks can sleep. With this change, I cannot trigger any lockdep warnings. [ 6.386519] ====================================================== [ 6.387203] WARNING: possible circular locking dependency detected [ 6.387965] 5.17.0-0.rc0.20220117git0c947b893d69.68.test.fc36.x86_64 #1 Not tainted [ 6.388899] ------------------------------------------------------ [ 6.389657] makedumpfile/542 is trying to acquire lock: [ 6.390308] ffffffff832d2eb8 (vmcore_cb_rwsem){.+.+}-{3:3}, at: mmap_vmcore+0x340/0x580 [ 6.391290] [ 6.391290] but task is already holding lock: [ 6.391978] ffff8880af226438 (&mm->mmap_lock#2){++++}-{3:3}, at: vm_mmap_pgoff+0x84/0x150 [ 6.392898] [ 6.392898] which lock already depends on the new lock. [ 6.392898] [ 6.393866] [ 6.393866] the existing dependency chain (in reverse order) is: [ 6.394762] [ 6.394762] -> #1 (&mm->mmap_lock#2){++++}-{3:3}: [ 6.395530] lock_acquire+0xc3/0x1a0 [ 6.396047] __might_fault+0x4e/0x70 [ 6.396562] _copy_to_user+0x1f/0x90 [ 6.397093] __copy_oldmem_page+0x72/0xc0 [ 6.397663] read_from_oldmem+0x77/0x1e0 [ 6.398229] read_vmcore+0x2c2/0x310 [ 6.398742] proc_reg_read+0x47/0xa0 [ 6.399265] vfs_read+0x101/0x340 [ 6.399751] __x64_sys_pread64+0x5d/0xa0 [ 6.400314] do_syscall_64+0x43/0x90 [ 6.400778] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 6.401390] [ 6.401390] -> #0 (vmcore_cb_rwsem){.+.+}-{3:3}: [ 6.402063] validate_chain+0x9f4/0x2670 [ 6.402560] __lock_acquire+0x8f7/0xbc0 [ 6.403054] lock_acquire+0xc3/0x1a0 [ 6.403509] down_read+0x4a/0x140 [ 6.403948] mmap_vmcore+0x340/0x580 [ 6.404403] proc_reg_mmap+0x3e/0x90 [ 6.404866] mmap_region+0x504/0x880 [ 6.405322] do_mmap+0x38a/0x520 [ 6.405744] vm_mmap_pgoff+0xc1/0x150 [ 6.406258] ksys_mmap_pgoff+0x178/0x200 [ 6.406823] do_syscall_64+0x43/0x90 [ 6.407339] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 6.407975] [ 6.407975] other info that might help us debug this: [ 6.407975] [ 6.408945] Possible unsafe locking scenario: [ 6.408945] [ 6.409684] CPU0 CPU1 [ 6.410196] ---- ---- [ 6.410703] lock(&mm->mmap_lock#2); [ 6.411121] lock(vmcore_cb_rwsem); [ 6.411792] lock(&mm->mmap_lock#2); [ 6.412465] lock(vmcore_cb_rwsem); [ 6.412873] [ 6.412873] *** DEADLOCK *** [ 6.412873] [ 6.413522] 1 lock held by makedumpfile/542: [ 6.414006] #0: ffff8880af226438 (&mm->mmap_lock#2){++++}-{3:3}, at: vm_mmap_pgoff+0x84/0x150 [ 6.414944] [ 6.414944] stack backtrace: [ 6.415432] CPU: 0 PID: 542 Comm: makedumpfile Not tainted 5.17.0-0.rc0.20220117git0c947b893d69.68.test.fc36.x86_64 #1 [ 6.416581] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 [ 6.417272] Call Trace: [ 6.417593] <TASK> [ 6.417882] dump_stack_lvl+0x5d/0x78 [ 6.418346] print_circular_bug+0x5d7/0x5f0 [ 6.418821] ? stack_trace_save+0x3a/0x50 [ 6.419273] ? save_trace+0x3d/0x330 [ 6.419681] check_noncircular+0xd1/0xe0 [ 6.420217] validate_chain+0x9f4/0x2670 [ 6.420715] ? __lock_acquire+0x8f7/0xbc0 [ 6.421234] ? __lock_acquire+0x8f7/0xbc0 [ 6.421685] __lock_acquire+0x8f7/0xbc0 [ 6.422127] lock_acquire+0xc3/0x1a0 [ 6.422535] ? mmap_vmcore+0x340/0x580 [ 6.422965] ? lock_is_held_type+0xe2/0x140 [ 6.423432] ? mmap_vmcore+0x340/0x580 [ 6.423893] down_read+0x4a/0x140 [ 6.424321] ? mmap_vmcore+0x340/0x580 [ 6.424800] mmap_vmcore+0x340/0x580 [ 6.425237] ? vm_area_alloc+0x1c/0x60 [ 6.425661] ? trace_kmem_cache_alloc+0x30/0xe0 [ 6.426174] ? kmem_cache_alloc+0x1e0/0x2f0 [ 6.426641] proc_reg_mmap+0x3e/0x90 [ 6.427052] mmap_region+0x504/0x880 [ 6.427462] do_mmap+0x38a/0x520 [ 6.427842] vm_mmap_pgoff+0xc1/0x150 [ 6.428260] ksys_mmap_pgoff+0x178/0x200 [ 6.428701] do_syscall_64+0x43/0x90 [ 6.429126] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 6.429745] RIP: 0033:0x7fc7359b8fc7 [ 6.430157] Code: 00 00 00 89 ef e8 69 b3 ff ff eb e4 e8 c2 64 01 00 66 90 f3 0f 1e fa 41 89 ca 41 f7 c1 ff 0f 00 00 75 10 b8 09 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 21 c3 48 8b 05 21 7e 0e 00 64 c7 00 16 00 00 [ 6.432147] RSP: 002b:00007fff35b4c208 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 [ 6.432970] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007fc7359b8fc7 [ 6.433746] RDX: 0000000000000001 RSI: 0000000000400000 RDI: 0000000000000000 [ 6.434529] RBP: 000055a1125ecf10 R08: 0000000000000003 R09: 0000000000002000 [ 6.435310] R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000002000 [ 6.436093] R13: 0000000000400000 R14: 000055a1124269e2 R15: 0000000000000000 [ 6.436887] </TASK> Link: https://lkml.kernel.org/r/20220119193417.100385-1-david@redhat.com Fixes: cc5f270 ("proc/vmcore: convert oldmem_pfn_is_ram callback to more generic vmcore callbacks") Signed-off-by: David Hildenbrand <david@redhat.com> Reported-by: Baoquan He <bhe@redhat.com> Acked-by: Baoquan He <bhe@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Dave Young <dyoung@redhat.com> Cc: "Paul E. McKenney" <paulmck@kernel.org> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>

Patch series "mm: COW fixes part 1: fix the COW security issue for THP and swap", v3. This series attempts to optimize and streamline the COW logic for ordinary anon pages and THP anon pages, fixing two remaining instances of CVE-2020-29374 in do_swap_page() and do_huge_pmd_wp_page(): information can leak from a parent process to a child process via anonymous pages shared during fork(). This issue, including other related COW issues, has been summarized in [2]: " 1. Observing Memory Modifications of Private Pages From A Child Process Long story short: process-private memory might not be as private as you think once you fork(): successive modifications of private memory regions in the parent process can still be observed by the child process, for example, by smart use of vmsplice()+munmap(). The core problem is that pinning pages readable in a child process, such as done via the vmsplice system call, can result in a child process observing memory modifications done in the parent process the child is not supposed to observe. [1] contains an excellent summary and [2] contains further details. This issue was assigned CVE-2020-29374 [9]. For this to trigger, it's required to use a fork() without subsequent exec(), for example, as used under Android zygote. Without further details about an application that forks less-privileged child processes, one cannot really say what's actually affected and what's not -- see the details section the end of this mail for a short sshd/openssh analysis. While commit 1783985 ("gup: document and work around "COW can break either way" issue") fixed this issue and resulted in other problems (e.g., ptrace on pmem), commit 09854ba ("mm: do_wp_page() simplification") re-introduced part of the problem unfortunately. The original reproducer can be modified quite easily to use THP [3] and make the issue appear again on upstream kernels. I modified it to use hugetlb [4] and it triggers as well. The problem is certainly less severe with hugetlb than with THP; it merely highlights that we still have plenty of open holes we should be closing/fixing. Regarding vmsplice(), the only known workaround is to disallow the vmsplice() system call ... or disable THP and hugetlb. But who knows what else is affected (RDMA? O_DIRECT?) to achieve the same goal -- in the end, it's a more generic issue. " This security issue was first reported by Jann Horn on 27 May 2020 and it currently affects anonymous pages during swapin, anonymous THP and hugetlb. This series tackles anonymous pages during swapin and anonymous THP: * do_swap_page() for handling COW on PTEs during swapin directly * do_huge_pmd_wp_page() for handling COW on PMD-mapped THP during write faults With this series, we'll apply the same COW logic we have in do_wp_page() to all swappable anon pages: don't reuse (map writable) the page in case there are additional references (page_count() != 1). All users of reuse_swap_page() are remove, and consequently reuse_swap_page() is removed. In general, we're struggling with the following COW-related issues: (1) "missed COW": we miss to copy on write and reuse the page (map it writable) although we must copy because there are pending references from another process to this page. The result is a security issue. (2) "wrong COW": we copy on write although we wouldn't have to and shouldn't: if there are valid GUP references, they will become out of sync with the pages mapped into the page table. We fail to detect that such a page can be reused safely, especially if never more than a single process mapped the page. The result is an intra process memory corruption. (3) "unnecessary COW": we copy on write although we wouldn't have to: performance degradation and temporary increases swap+memory consumption can be the result. While this series fixes (1) for swappable anon pages, it tries to reduce reported cases of (3) first as good and easy as possible to limit the impact when streamlining. The individual patches try to describe in which cases we will run into (3). This series certainly makes (2) worse for THP, because a THP will now get PTE-mapped on write faults if there are additional references, even if there was only ever a single process involved: once PTE-mapped, we'll copy each and every subpage and won't reuse any subpage as long as the underlying compound page wasn't split. I'm working on an approach to fix (2) and improve (3): PageAnonExclusive to mark anon pages that are exclusive to a single process, allow GUP pins only on such exclusive pages, and allow turning exclusive pages shared (clearing PageAnonExclusive) only if there are no GUP pins. Anon pages with PageAnonExclusive set never have to be copied during write faults, but eventually during fork() if they cannot be turned shared. The improved reuse logic in this series will essentially also be the logic to reset PageAnonExclusive. This work will certainly take a while, but I'm planning on sharing details before having code fully ready. #1-#5 can be applied independently of the rest. torvalds#6-torvalds#9 are mostly only cleanups related to reuse_swap_page(). Notes: * For now, I'll leave hugetlb code untouched: "unnecessary COW" might easily break existing setups because hugetlb pages are a scarce resource and we could just end up having to crash the application when we run out of hugetlb pages. We have to be very careful and the security aspect with hugetlb is most certainly less relevant than for unprivileged anon pages. * Instead of lru_add_drain() we might actually just drain the lru_add list or even just remove the single page of interest from the lru_add list. This would require a new helper function, and could be added if the conditional lru_add_drain() turn out to be a problem. * I extended the test case already included in [1] to also test for the newly found do_swap_page() case. I'll send that out separately once/if this part was merged. [1] https://lkml.kernel.org/r/20211217113049.23850-1-david@redhat.com [2] https://lore.kernel.org/r/3ae33b08-d9ef-f846-56fb-645e3b9b4c66@redhat.com This patch (of 9): Liang Zhang reported [1] that the current COW logic in do_wp_page() is sub-optimal when it comes to swap+read fault+write fault of anonymous pages that have a single user, visible via a performance degradation in the redis benchmark. Something similar was previously reported [2] by Nadav with a simple reproducer. After we put an anon page into the swapcache and unmapped it from a single process, that process might read that page again and refault it read-only. If that process then writes to that page, the process is actually the exclusive user of the page, however, the COW logic in do_co_page() won't be able to reuse it due to the additional reference from the swapcache. Let's optimize for pages that have been added to the swapcache but only have an exclusive user. Try removing the swapcache reference if there is hope that we're the exclusive user. We will fail removing the swapcache reference in two scenarios: (1) There are additional swap entries referencing the page: copying instead of reusing is the right thing to do. (2) The page is under writeback: theoretically we might be able to reuse in some cases, however, we cannot remove the additional reference and will have to copy. Note that we'll only try removing the page from the swapcache when it's highly likely that we'll be the exclusive owner after removing the page from the swapache. As we're about to map that page writable and redirty it, that should not affect reclaim but is rather the right thing to do. Further, we might have additional references from the LRU pagevecs, which will force us to copy instead of being able to reuse. We'll try handling such references for some scenarios next. Concurrent writeback cannot be handled easily and we'll always have to copy. While at it, remove the superfluous page_mapcount() check: it's implicitly covered by the page_count() for ordinary anon pages. [1] https://lkml.kernel.org/r/20220113140318.11117-1-zhangliang5@huawei.com [2] https://lkml.kernel.org/r/0480D692-D9B2-429A-9A88-9BBA1331AC3A@gmail.com Link: https://lkml.kernel.org/r/20220131162940.210846-2-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reported-by: Liang Zhang <zhangliang5@huawei.com> Reported-by: Nadav Amit <nadav.amit@gmail.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: David Rientjes <rientjes@google.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Yang Shi <shy828301@gmail.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Jann Horn <jannh@google.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Rik van Riel <riel@surriel.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Peter Xu <peterx@redhat.com> Cc: Don Dutile <ddutile@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>

xairy force-pushed the usb-kcov branch from 7244f9e to 53037cd Compare June 12, 2018 12:42

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kcov: collect coverage from remote threads

abc2015

xairy force-pushed the usb-kcov branch from a9ffe61 to abc2015 Compare June 18, 2018 16:25

kcov: collect coverage from remote threads #1

kcov: collect coverage from remote threads #1

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xairy commented Jun 12, 2018

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xairy commented Jun 12, 2018

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xairy commented Jun 13, 2018

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