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(Compile fix) Fix backported security fix for CVE-2020-14386 #51

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(Compile fix) Fix backported security fix for CVE-2020-14386 #51

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flawedworld
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@flawedworld flawedworld commented Sep 12, 2020

The patch sent to the mailing list for the latest kernel requires this commit to build. This is also relevant to 4.14.

Compilation will fail otherwise giving:

net/packet/af_packet.c:2230:19: error: no member named 'tp_drops' in 'struct packet_sock' atomic_inc(&po->tp_drops); ~~ ^

Or Cohen and others added 2 commits September 9, 2020 21:31
Using tp_reserve to calculate netoff can overflow as
tp_reserve is unsigned int and netoff is unsigned short.

This may lead to macoff receving a smaller value then
sizeof(struct virtio_net_hdr), and if po->has_vnet_hdr
is set, an out-of-bounds write will occur when
calling virtio_net_hdr_from_skb.

The bug is fixed by converting netoff to unsigned int
and checking if it exceeds USHRT_MAX.

This addresses CVE-2020-14386

Fixes: 8913336 ("packet: add PACKET_RESERVE sockopt")
Signed-off-by: Or Cohen <orcohen@paloaltonetworks.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Under DDOS, we want to be able to increment tp_drops without
touching the spinlock. This will help readers to drain
the receive queue slightly faster :/

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
@flawedworld flawedworld changed the title (Compile fix) Fix backport of CVE-2020-14386 (Compile fix) Fix backported security fix for CVE-2020-14386 Sep 13, 2020
@anthraxx anthraxx added the bug Something isn't working label Sep 13, 2020
@anthraxx anthraxx self-assigned this Sep 13, 2020
@anthraxx
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anthraxx commented Sep 23, 2020

so, its not as easy as just cherry picking another patch, this is just a tiny part of the whole "packet-DDOS" merge that misses some important bits. I think its a safer call to fix the patch independently for pre refactoring trees.

I gonna test a different approach, it looks we can simply replace the code with using the old spin locking mechanism.
something like:

if (netoff > USHRT_MAX) {
    spin_lock(&sk->sk_receive_queue.lock);
    po->stats.stats1.tp_drops++;
    spin_unlock(&sk->sk_receive_queue.lock);
    goto drop_n_restore;
}

I gonna spend some testing time and adjust the faulty backport for the pre refactoring trees.

@flawedworld
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Sounds good, I wont lie, my solution is lazy, but I do agree with you.

@anthraxx
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@flawedworld can you give patch 7b00ca2 a try?

@flawedworld
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@anthraxx Yeah, I'll see if I can sneak a compile in before I wrap up for the day, otherwise I will try tomorrow.

@flawedworld
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@anthraxx Compiled fine for me. Looks good!

@anthraxx
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patch adjusted in 4.14 and 4.19 tree

@anthraxx anthraxx closed this Sep 26, 2020
@flawedworld flawedworld deleted the 4.19 branch October 7, 2020 23:54
anthraxx pushed a commit that referenced this pull request Nov 5, 2020
[ Upstream commit 27dada0 ]

The defer ops code has been finishing items in the wrong order -- if a
top level defer op creates items A and B, and finishing item A creates
more defer ops A1 and A2, we'll put the new items on the end of the
chain and process them in the order A B A1 A2.  This is kind of weird,
since it's convenient for programmers to be able to think of A and B as
an ordered sequence where all the sub-tasks for A must finish before we
move on to B, e.g. A A1 A2 D.

Right now, our log intent items are not so complex that this matters,
but this will become important for the atomic extent swapping patchset.
In order to maintain correct reference counting of extents, we have to
unmap and remap extents in that order, and we want to complete that work
before moving on to the next range that the user wants to swap.  This
patch fixes defer ops to satsify that requirement.

The primary symptom of the incorrect order was noticed in an early
performance analysis of the atomic extent swap code.  An astonishingly
large number of deferred work items accumulated when userspace requested
an atomic update of two very fragmented files.  The cause of this was
traced to the same ordering bug in the inner loop of
xfs_defer_finish_noroll.

If the ->finish_item method of a deferred operation queues new deferred
operations, those new deferred ops are appended to the tail of the
pending work list.  To illustrate, say that a caller creates a
transaction t0 with four deferred operations D0-D3.  The first thing
defer ops does is roll the transaction to t1, leaving us with:

t1: D0(t0), D1(t0), D2(t0), D3(t0)

Let's say that finishing each of D0-D3 will create two new deferred ops.
After finish D0 and roll, we'll have the following chain:

t2: D1(t0), D2(t0), D3(t0), d4(t1), d5(t1)

d4 and d5 were logged to t1.  Notice that while we're about to start
work on D1, we haven't actually completed all the work implied by D0
being finished.  So far we've been careful (or lucky) to structure the
dfops callers such that D1 doesn't depend on d4 or d5 being finished,
but this is a potential logic bomb.

There's a second problem lurking.  Let's see what happens as we finish
D1-D3:

t3: D2(t0), D3(t0), d4(t1), d5(t1), d6(t2), d7(t2)
t4: D3(t0), d4(t1), d5(t1), d6(t2), d7(t2), d8(t3), d9(t3)
t5: d4(t1), d5(t1), d6(t2), d7(t2), d8(t3), d9(t3), d10(t4), d11(t4)

Let's say that d4-d11 are simple work items that don't queue any other
operations, which means that we can complete each d4 and roll to t6:

t6: d5(t1), d6(t2), d7(t2), d8(t3), d9(t3), d10(t4), d11(t4)
t7: d6(t2), d7(t2), d8(t3), d9(t3), d10(t4), d11(t4)
...
t11: d10(t4), d11(t4)
t12: d11(t4)
<done>

When we try to roll to transaction #12, we're holding defer op d11,
which we logged way back in t4.  This means that the tail of the log is
pinned at t4.  If the log is very small or there are a lot of other
threads updating metadata, this means that we might have wrapped the log
and cannot get roll to t11 because there isn't enough space left before
we'd run into t4.

Let's shift back to the original failure.  I mentioned before that I
discovered this flaw while developing the atomic file update code.  In
that scenario, we have a defer op (D0) that finds a range of file blocks
to remap, creates a handful of new defer ops to do that, and then asks
to be continued with however much work remains.

So, D0 is the original swapext deferred op.  The first thing defer ops
does is rolls to t1:

t1: D0(t0)

We try to finish D0, logging d1 and d2 in the process, but can't get all
the work done.  We log a done item and a new intent item for the work
that D0 still has to do, and roll to t2:

t2: D0'(t1), d1(t1), d2(t1)

We roll and try to finish D0', but still can't get all the work done, so
we log a done item and a new intent item for it, requeue D0 a second
time, and roll to t3:

t3: D0''(t2), d1(t1), d2(t1), d3(t2), d4(t2)

If it takes 48 more rolls to complete D0, then we'll finally dispense
with D0 in t50:

t50: D<fifty primes>(t49), d1(t1), ..., d102(t50)

We then try to roll again to get a chain like this:

t51: d1(t1), d2(t1), ..., d101(t50), d102(t50)
...
t152: d102(t50)
<done>

Notice that in rolling to transaction #51, we're holding on to a log
intent item for d1 that was logged in transaction #1.  This means that
the tail of the log is pinned at t1.  If the log is very small or there
are a lot of other threads updating metadata, this means that we might
have wrapped the log and cannot roll to t51 because there isn't enough
space left before we'd run into t1.  This is of course problem #2 again.

But notice the third problem with this scenario: we have 102 defer ops
tied to this transaction!  Each of these items are backed by pinned
kernel memory, which means that we risk OOM if the chains get too long.

Yikes.  Problem #1 is a subtle logic bomb that could hit someone in the
future; problem #2 applies (rarely) to the current upstream, and problem
#3 applies to work under development.

This is not how incremental deferred operations were supposed to work.
The dfops design of logging in the same transaction an intent-done item
and a new intent item for the work remaining was to make it so that we
only have to juggle enough deferred work items to finish that one small
piece of work.  Deferred log item recovery will find that first
unfinished work item and restart it, no matter how many other intent
items might follow it in the log.  Therefore, it's ok to put the new
intents at the start of the dfops chain.

For the first example, the chains look like this:

t2: d4(t1), d5(t1), D1(t0), D2(t0), D3(t0)
t3: d5(t1), D1(t0), D2(t0), D3(t0)
...
t9: d9(t7), D3(t0)
t10: D3(t0)
t11: d10(t10), d11(t10)
t12: d11(t10)

For the second example, the chains look like this:

t1: D0(t0)
t2: d1(t1), d2(t1), D0'(t1)
t3: d2(t1), D0'(t1)
t4: D0'(t1)
t5: d1(t4), d2(t4), D0''(t4)
...
t148: D0<50 primes>(t147)
t149: d101(t148), d102(t148)
t150: d102(t148)
<done>

This actually sucks more for pinning the log tail (we try to roll to t10
while holding an intent item that was logged in t1) but we've solved
problem #1.  We've also reduced the maximum chain length from:

    sum(all the new items) + nr_original_items

to:

    max(new items that each original item creates) + nr_original_items

This solves problem #3 by sharply reducing the number of defer ops that
can be attached to a transaction at any given time.  The change makes
the problem of log tail pinning worse, but is improvement we need to
solve problem #2.  Actually solving #2, however, is left to the next
patch.

Note that a subsequent analysis of some hard-to-trigger reflink and COW
livelocks on extremely fragmented filesystems (or systems running a lot
of IO threads) showed the same symptoms -- uncomfortably large numbers
of incore deferred work items and occasional stalls in the transaction
grant code while waiting for log reservations.  I think this patch and
the next one will also solve these problems.

As originally written, the code used list_splice_tail_init instead of
list_splice_init, so change that, and leave a short comment explaining
our actions.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
anthraxx pushed a commit that referenced this pull request Nov 5, 2020
commit 8062426 upstream.

With LOCKDEP enabled, CTI driver triggers the following splat due
to uninitialized lock class for dynamically allocated attribute
objects.

[    5.372901] coresight etm0: CPU0: ETM v4.0 initialized
[    5.376694] coresight etm1: CPU1: ETM v4.0 initialized
[    5.380785] coresight etm2: CPU2: ETM v4.0 initialized
[    5.385851] coresight etm3: CPU3: ETM v4.0 initialized
[    5.389808] BUG: key ffff00000564a798 has not been registered!
[    5.392456] ------------[ cut here ]------------
[    5.398195] DEBUG_LOCKS_WARN_ON(1)
[    5.398233] WARNING: CPU: 1 PID: 32 at kernel/locking/lockdep.c:4623 lockdep_init_map_waits+0x14c/0x260
[    5.406149] Modules linked in:
[    5.415411] CPU: 1 PID: 32 Comm: kworker/1:1 Not tainted 5.9.0-12034-gbbe85027ce80 #51
[    5.418553] Hardware name: Qualcomm Technologies, Inc. APQ 8016 SBC (DT)
[    5.426453] Workqueue: events amba_deferred_retry_func
[    5.433299] pstate: 40000005 (nZcv daif -PAN -UAO -TCO BTYPE=--)
[    5.438252] pc : lockdep_init_map_waits+0x14c/0x260
[    5.444410] lr : lockdep_init_map_waits+0x14c/0x260
[    5.449007] sp : ffff800012bbb720
...

[    5.531561] Call trace:
[    5.536847]  lockdep_init_map_waits+0x14c/0x260
[    5.539027]  __kernfs_create_file+0xa8/0x1c8
[    5.543539]  sysfs_add_file_mode_ns+0xd0/0x208
[    5.548054]  internal_create_group+0x118/0x3c8
[    5.552307]  internal_create_groups+0x58/0xb8
[    5.556733]  sysfs_create_groups+0x2c/0x38
[    5.561160]  device_add+0x2d8/0x768
[    5.565148]  device_register+0x28/0x38
[    5.568537]  coresight_register+0xf8/0x320
[    5.572358]  cti_probe+0x1b0/0x3f0

...

Fix this by initializing the attributes when they are allocated.

Fixes: 3c5597e ("coresight: cti: Add connection information to sysfs")
Reported-by: Leo Yan <leo.yan@linaro.org>
Tested-by: Leo Yan <leo.yan@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20201029164559.1268531-2-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
anthraxx pushed a commit that referenced this pull request Dec 2, 2020
[ Upstream commit 1922a46 ]

If a user unbinds and re-binds a NC-SI aware driver the kernel will
attempt to register the netlink interface at runtime. The structure is
marked __ro_after_init so registration fails spectacularly at this point.

 # echo 1e660000.ethernet > /sys/bus/platform/drivers/ftgmac100/unbind
 # echo 1e660000.ethernet > /sys/bus/platform/drivers/ftgmac100/bind
  ftgmac100 1e660000.ethernet: Read MAC address 52:54:00:12:34:56 from chip
  ftgmac100 1e660000.ethernet: Using NCSI interface
  8<--- cut here ---
  Unable to handle kernel paging request at virtual address 80a8f858
  pgd = 8c768dd6
  [80a8f858] *pgd=80a0841e(bad)
  Internal error: Oops: 80d [#1] SMP ARM
  CPU: 0 PID: 116 Comm: sh Not tainted 5.10.0-rc3-next-20201111-00003-gdd25b227ec1e #51
  Hardware name: Generic DT based system
  PC is at genl_register_family+0x1f8/0x6d4
  LR is at 0xff26ffff
  pc : [<8073f930>]    lr : [<ff26ffff>]    psr: 20000153
  sp : 8553bc80  ip : 81406244  fp : 8553bd04
  r10: 8085d12c  r9 : 80a8f73c  r8 : 85739000
  r7 : 00000017  r6 : 80a8f860  r5 : 80c8ab98  r4 : 80a8f858
  r3 : 00000000  r2 : 00000000  r1 : 81406130  r0 : 00000017
  Flags: nzCv  IRQs on  FIQs off  Mode SVC_32  ISA ARM  Segment none
  Control: 00c5387d  Table: 85524008  DAC: 00000051
  Process sh (pid: 116, stack limit = 0x1f1988d6)
 ...
  Backtrace:
  [<8073f738>] (genl_register_family) from [<80860ac0>] (ncsi_init_netlink+0x20/0x48)
   r10:8085d12c r9:80c8fb0c r8:85739000 r7:00000000 r6:81218000 r5:85739000
   r4:8121c000
  [<80860aa0>] (ncsi_init_netlink) from [<8085d740>] (ncsi_register_dev+0x1b0/0x210)
   r5:8121c400 r4:8121c000
  [<8085d590>] (ncsi_register_dev) from [<805a8060>] (ftgmac100_probe+0x6e0/0x778)
   r10:00000004 r9:80950228 r8:8115bc10 r7:8115ab00 r6:9eae2c24 r5:813b6f88
   r4:85739000
  [<805a7980>] (ftgmac100_probe) from [<805355ec>] (platform_drv_probe+0x58/0xa8)
   r9:80c76bb0 r8:00000000 r7:80cd4974 r6:80c76bb0 r5:8115bc10 r4:00000000
  [<80535594>] (platform_drv_probe) from [<80532d58>] (really_probe+0x204/0x514)
   r7:80cd4974 r6:00000000 r5:80cd4868 r4:8115bc10

Jakub pointed out that ncsi_register_dev is obviously broken, because
there is only one family so it would never work if there was more than
one ncsi netdev.

Fix the crash by registering the netlink family once on boot, and drop
the code to unregister it.

Fixes: 955dc68 ("net/ncsi: Add generic netlink family")
Signed-off-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Samuel Mendoza-Jonas <sam@mendozajonas.com>
Link: https://lore.kernel.org/r/20201112061210.914621-1-joel@jms.id.au
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
anthraxx pushed a commit that referenced this pull request Dec 2, 2020
[ Upstream commit 1922a46 ]

If a user unbinds and re-binds a NC-SI aware driver the kernel will
attempt to register the netlink interface at runtime. The structure is
marked __ro_after_init so registration fails spectacularly at this point.

 # echo 1e660000.ethernet > /sys/bus/platform/drivers/ftgmac100/unbind
 # echo 1e660000.ethernet > /sys/bus/platform/drivers/ftgmac100/bind
  ftgmac100 1e660000.ethernet: Read MAC address 52:54:00:12:34:56 from chip
  ftgmac100 1e660000.ethernet: Using NCSI interface
  8<--- cut here ---
  Unable to handle kernel paging request at virtual address 80a8f858
  pgd = 8c768dd6
  [80a8f858] *pgd=80a0841e(bad)
  Internal error: Oops: 80d [#1] SMP ARM
  CPU: 0 PID: 116 Comm: sh Not tainted 5.10.0-rc3-next-20201111-00003-gdd25b227ec1e #51
  Hardware name: Generic DT based system
  PC is at genl_register_family+0x1f8/0x6d4
  LR is at 0xff26ffff
  pc : [<8073f930>]    lr : [<ff26ffff>]    psr: 20000153
  sp : 8553bc80  ip : 81406244  fp : 8553bd04
  r10: 8085d12c  r9 : 80a8f73c  r8 : 85739000
  r7 : 00000017  r6 : 80a8f860  r5 : 80c8ab98  r4 : 80a8f858
  r3 : 00000000  r2 : 00000000  r1 : 81406130  r0 : 00000017
  Flags: nzCv  IRQs on  FIQs off  Mode SVC_32  ISA ARM  Segment none
  Control: 00c5387d  Table: 85524008  DAC: 00000051
  Process sh (pid: 116, stack limit = 0x1f1988d6)
 ...
  Backtrace:
  [<8073f738>] (genl_register_family) from [<80860ac0>] (ncsi_init_netlink+0x20/0x48)
   r10:8085d12c r9:80c8fb0c r8:85739000 r7:00000000 r6:81218000 r5:85739000
   r4:8121c000
  [<80860aa0>] (ncsi_init_netlink) from [<8085d740>] (ncsi_register_dev+0x1b0/0x210)
   r5:8121c400 r4:8121c000
  [<8085d590>] (ncsi_register_dev) from [<805a8060>] (ftgmac100_probe+0x6e0/0x778)
   r10:00000004 r9:80950228 r8:8115bc10 r7:8115ab00 r6:9eae2c24 r5:813b6f88
   r4:85739000
  [<805a7980>] (ftgmac100_probe) from [<805355ec>] (platform_drv_probe+0x58/0xa8)
   r9:80c76bb0 r8:00000000 r7:80cd4974 r6:80c76bb0 r5:8115bc10 r4:00000000
  [<80535594>] (platform_drv_probe) from [<80532d58>] (really_probe+0x204/0x514)
   r7:80cd4974 r6:00000000 r5:80cd4868 r4:8115bc10

Jakub pointed out that ncsi_register_dev is obviously broken, because
there is only one family so it would never work if there was more than
one ncsi netdev.

Fix the crash by registering the netlink family once on boot, and drop
the code to unregister it.

Fixes: 955dc68 ("net/ncsi: Add generic netlink family")
Signed-off-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Samuel Mendoza-Jonas <sam@mendozajonas.com>
Link: https://lore.kernel.org/r/20201112061210.914621-1-joel@jms.id.au
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
anthraxx pushed a commit that referenced this pull request Dec 2, 2020
[ Upstream commit 1922a46 ]

If a user unbinds and re-binds a NC-SI aware driver the kernel will
attempt to register the netlink interface at runtime. The structure is
marked __ro_after_init so registration fails spectacularly at this point.

 # echo 1e660000.ethernet > /sys/bus/platform/drivers/ftgmac100/unbind
 # echo 1e660000.ethernet > /sys/bus/platform/drivers/ftgmac100/bind
  ftgmac100 1e660000.ethernet: Read MAC address 52:54:00:12:34:56 from chip
  ftgmac100 1e660000.ethernet: Using NCSI interface
  8<--- cut here ---
  Unable to handle kernel paging request at virtual address 80a8f858
  pgd = 8c768dd6
  [80a8f858] *pgd=80a0841e(bad)
  Internal error: Oops: 80d [#1] SMP ARM
  CPU: 0 PID: 116 Comm: sh Not tainted 5.10.0-rc3-next-20201111-00003-gdd25b227ec1e #51
  Hardware name: Generic DT based system
  PC is at genl_register_family+0x1f8/0x6d4
  LR is at 0xff26ffff
  pc : [<8073f930>]    lr : [<ff26ffff>]    psr: 20000153
  sp : 8553bc80  ip : 81406244  fp : 8553bd04
  r10: 8085d12c  r9 : 80a8f73c  r8 : 85739000
  r7 : 00000017  r6 : 80a8f860  r5 : 80c8ab98  r4 : 80a8f858
  r3 : 00000000  r2 : 00000000  r1 : 81406130  r0 : 00000017
  Flags: nzCv  IRQs on  FIQs off  Mode SVC_32  ISA ARM  Segment none
  Control: 00c5387d  Table: 85524008  DAC: 00000051
  Process sh (pid: 116, stack limit = 0x1f1988d6)
 ...
  Backtrace:
  [<8073f738>] (genl_register_family) from [<80860ac0>] (ncsi_init_netlink+0x20/0x48)
   r10:8085d12c r9:80c8fb0c r8:85739000 r7:00000000 r6:81218000 r5:85739000
   r4:8121c000
  [<80860aa0>] (ncsi_init_netlink) from [<8085d740>] (ncsi_register_dev+0x1b0/0x210)
   r5:8121c400 r4:8121c000
  [<8085d590>] (ncsi_register_dev) from [<805a8060>] (ftgmac100_probe+0x6e0/0x778)
   r10:00000004 r9:80950228 r8:8115bc10 r7:8115ab00 r6:9eae2c24 r5:813b6f88
   r4:85739000
  [<805a7980>] (ftgmac100_probe) from [<805355ec>] (platform_drv_probe+0x58/0xa8)
   r9:80c76bb0 r8:00000000 r7:80cd4974 r6:80c76bb0 r5:8115bc10 r4:00000000
  [<80535594>] (platform_drv_probe) from [<80532d58>] (really_probe+0x204/0x514)
   r7:80cd4974 r6:00000000 r5:80cd4868 r4:8115bc10

Jakub pointed out that ncsi_register_dev is obviously broken, because
there is only one family so it would never work if there was more than
one ncsi netdev.

Fix the crash by registering the netlink family once on boot, and drop
the code to unregister it.

Fixes: 955dc68 ("net/ncsi: Add generic netlink family")
Signed-off-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Samuel Mendoza-Jonas <sam@mendozajonas.com>
Link: https://lore.kernel.org/r/20201112061210.914621-1-joel@jms.id.au
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
anthraxx pushed a commit that referenced this pull request May 23, 2021
[ Upstream commit d5027ca ]

Ritesh reported a bug [1] against UML, noting that it crashed on
startup. The backtrace shows the following (heavily redacted):

(gdb) bt
...
 #26 0x0000000060015b5d in sem_init () at ipc/sem.c:268
 #27 0x00007f89906d92f7 in ?? () from /lib/x86_64-linux-gnu/libcom_err.so.2
 #28 0x00007f8990ab8fb2 in call_init (...) at dl-init.c:72
...
 #40 0x00007f89909bf3a6 in nss_load_library (...) at nsswitch.c:359
...
 #44 0x00007f8990895e35 in _nss_compat_getgrnam_r (...) at nss_compat/compat-grp.c:486
 #45 0x00007f8990968b85 in __getgrnam_r [...]
 #46 0x00007f89909d6b77 in grantpt [...]
 #47 0x00007f8990a9394e in __GI_openpty [...]
 #48 0x00000000604a1f65 in openpty_cb (...) at arch/um/os-Linux/sigio.c:407
 #49 0x00000000604a58d0 in start_idle_thread (...) at arch/um/os-Linux/skas/process.c:598
 #50 0x0000000060004a3d in start_uml () at arch/um/kernel/skas/process.c:45
 #51 0x00000000600047b2 in linux_main (...) at arch/um/kernel/um_arch.c:334
 #52 0x000000006000574f in main (...) at arch/um/os-Linux/main.c:144

indicating that the UML function openpty_cb() calls openpty(),
which internally calls __getgrnam_r(), which causes the nsswitch
machinery to get started.

This loads, through lots of indirection that I snipped, the
libcom_err.so.2 library, which (in an unknown function, "??")
calls sem_init().

Now, of course it wants to get libpthread's sem_init(), since
it's linked against libpthread. However, the dynamic linker
looks up that symbol against the binary first, and gets the
kernel's sem_init().

Hajime Tazaki noted that "objcopy -L" can localize a symbol,
so the dynamic linker wouldn't do the lookup this way. I tried,
but for some reason that didn't seem to work.

Doing the same thing in the linker script instead does seem to
work, though I cannot entirely explain - it *also* works if I
just add "VERSION { { global: *; }; }" instead, indicating that
something else is happening that I don't really understand. It
may be that explicitly doing that marks them with some kind of
empty version, and that's different from the default.

Explicitly marking them with a version breaks kallsyms, so that
doesn't seem to be possible.

Marking all the symbols as local seems correct, and does seem
to address the issue, so do that. Also do it for static link,
nsswitch libraries could still be loaded there.

[1] https://bugs.debian.org/983379

Reported-by: Ritesh Raj Sarraf <rrs@debian.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Tested-By: Ritesh Raj Sarraf <rrs@debian.org>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Sasha Levin <sashal@kernel.org>
anthraxx pushed a commit that referenced this pull request May 23, 2021
[ Upstream commit d5027ca ]

Ritesh reported a bug [1] against UML, noting that it crashed on
startup. The backtrace shows the following (heavily redacted):

(gdb) bt
...
 #26 0x0000000060015b5d in sem_init () at ipc/sem.c:268
 #27 0x00007f89906d92f7 in ?? () from /lib/x86_64-linux-gnu/libcom_err.so.2
 #28 0x00007f8990ab8fb2 in call_init (...) at dl-init.c:72
...
 #40 0x00007f89909bf3a6 in nss_load_library (...) at nsswitch.c:359
...
 #44 0x00007f8990895e35 in _nss_compat_getgrnam_r (...) at nss_compat/compat-grp.c:486
 #45 0x00007f8990968b85 in __getgrnam_r [...]
 #46 0x00007f89909d6b77 in grantpt [...]
 #47 0x00007f8990a9394e in __GI_openpty [...]
 #48 0x00000000604a1f65 in openpty_cb (...) at arch/um/os-Linux/sigio.c:407
 #49 0x00000000604a58d0 in start_idle_thread (...) at arch/um/os-Linux/skas/process.c:598
 #50 0x0000000060004a3d in start_uml () at arch/um/kernel/skas/process.c:45
 #51 0x00000000600047b2 in linux_main (...) at arch/um/kernel/um_arch.c:334
 #52 0x000000006000574f in main (...) at arch/um/os-Linux/main.c:144

indicating that the UML function openpty_cb() calls openpty(),
which internally calls __getgrnam_r(), which causes the nsswitch
machinery to get started.

This loads, through lots of indirection that I snipped, the
libcom_err.so.2 library, which (in an unknown function, "??")
calls sem_init().

Now, of course it wants to get libpthread's sem_init(), since
it's linked against libpthread. However, the dynamic linker
looks up that symbol against the binary first, and gets the
kernel's sem_init().

Hajime Tazaki noted that "objcopy -L" can localize a symbol,
so the dynamic linker wouldn't do the lookup this way. I tried,
but for some reason that didn't seem to work.

Doing the same thing in the linker script instead does seem to
work, though I cannot entirely explain - it *also* works if I
just add "VERSION { { global: *; }; }" instead, indicating that
something else is happening that I don't really understand. It
may be that explicitly doing that marks them with some kind of
empty version, and that's different from the default.

Explicitly marking them with a version breaks kallsyms, so that
doesn't seem to be possible.

Marking all the symbols as local seems correct, and does seem
to address the issue, so do that. Also do it for static link,
nsswitch libraries could still be loaded there.

[1] https://bugs.debian.org/983379

Reported-by: Ritesh Raj Sarraf <rrs@debian.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Tested-By: Ritesh Raj Sarraf <rrs@debian.org>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Sasha Levin <sashal@kernel.org>
anthraxx pushed a commit that referenced this pull request May 23, 2021
[ Upstream commit d5027ca ]

Ritesh reported a bug [1] against UML, noting that it crashed on
startup. The backtrace shows the following (heavily redacted):

(gdb) bt
...
 #26 0x0000000060015b5d in sem_init () at ipc/sem.c:268
 #27 0x00007f89906d92f7 in ?? () from /lib/x86_64-linux-gnu/libcom_err.so.2
 #28 0x00007f8990ab8fb2 in call_init (...) at dl-init.c:72
...
 #40 0x00007f89909bf3a6 in nss_load_library (...) at nsswitch.c:359
...
 #44 0x00007f8990895e35 in _nss_compat_getgrnam_r (...) at nss_compat/compat-grp.c:486
 #45 0x00007f8990968b85 in __getgrnam_r [...]
 #46 0x00007f89909d6b77 in grantpt [...]
 #47 0x00007f8990a9394e in __GI_openpty [...]
 #48 0x00000000604a1f65 in openpty_cb (...) at arch/um/os-Linux/sigio.c:407
 #49 0x00000000604a58d0 in start_idle_thread (...) at arch/um/os-Linux/skas/process.c:598
 #50 0x0000000060004a3d in start_uml () at arch/um/kernel/skas/process.c:45
 #51 0x00000000600047b2 in linux_main (...) at arch/um/kernel/um_arch.c:334
 #52 0x000000006000574f in main (...) at arch/um/os-Linux/main.c:144

indicating that the UML function openpty_cb() calls openpty(),
which internally calls __getgrnam_r(), which causes the nsswitch
machinery to get started.

This loads, through lots of indirection that I snipped, the
libcom_err.so.2 library, which (in an unknown function, "??")
calls sem_init().

Now, of course it wants to get libpthread's sem_init(), since
it's linked against libpthread. However, the dynamic linker
looks up that symbol against the binary first, and gets the
kernel's sem_init().

Hajime Tazaki noted that "objcopy -L" can localize a symbol,
so the dynamic linker wouldn't do the lookup this way. I tried,
but for some reason that didn't seem to work.

Doing the same thing in the linker script instead does seem to
work, though I cannot entirely explain - it *also* works if I
just add "VERSION { { global: *; }; }" instead, indicating that
something else is happening that I don't really understand. It
may be that explicitly doing that marks them with some kind of
empty version, and that's different from the default.

Explicitly marking them with a version breaks kallsyms, so that
doesn't seem to be possible.

Marking all the symbols as local seems correct, and does seem
to address the issue, so do that. Also do it for static link,
nsswitch libraries could still be loaded there.

[1] https://bugs.debian.org/983379

Reported-by: Ritesh Raj Sarraf <rrs@debian.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Tested-By: Ritesh Raj Sarraf <rrs@debian.org>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Sasha Levin <sashal@kernel.org>
anthraxx pushed a commit that referenced this pull request May 23, 2021
[ Upstream commit d5027ca ]

Ritesh reported a bug [1] against UML, noting that it crashed on
startup. The backtrace shows the following (heavily redacted):

(gdb) bt
...
 #26 0x0000000060015b5d in sem_init () at ipc/sem.c:268
 #27 0x00007f89906d92f7 in ?? () from /lib/x86_64-linux-gnu/libcom_err.so.2
 #28 0x00007f8990ab8fb2 in call_init (...) at dl-init.c:72
...
 #40 0x00007f89909bf3a6 in nss_load_library (...) at nsswitch.c:359
...
 #44 0x00007f8990895e35 in _nss_compat_getgrnam_r (...) at nss_compat/compat-grp.c:486
 #45 0x00007f8990968b85 in __getgrnam_r [...]
 #46 0x00007f89909d6b77 in grantpt [...]
 #47 0x00007f8990a9394e in __GI_openpty [...]
 #48 0x00000000604a1f65 in openpty_cb (...) at arch/um/os-Linux/sigio.c:407
 #49 0x00000000604a58d0 in start_idle_thread (...) at arch/um/os-Linux/skas/process.c:598
 #50 0x0000000060004a3d in start_uml () at arch/um/kernel/skas/process.c:45
 #51 0x00000000600047b2 in linux_main (...) at arch/um/kernel/um_arch.c:334
 #52 0x000000006000574f in main (...) at arch/um/os-Linux/main.c:144

indicating that the UML function openpty_cb() calls openpty(),
which internally calls __getgrnam_r(), which causes the nsswitch
machinery to get started.

This loads, through lots of indirection that I snipped, the
libcom_err.so.2 library, which (in an unknown function, "??")
calls sem_init().

Now, of course it wants to get libpthread's sem_init(), since
it's linked against libpthread. However, the dynamic linker
looks up that symbol against the binary first, and gets the
kernel's sem_init().

Hajime Tazaki noted that "objcopy -L" can localize a symbol,
so the dynamic linker wouldn't do the lookup this way. I tried,
but for some reason that didn't seem to work.

Doing the same thing in the linker script instead does seem to
work, though I cannot entirely explain - it *also* works if I
just add "VERSION { { global: *; }; }" instead, indicating that
something else is happening that I don't really understand. It
may be that explicitly doing that marks them with some kind of
empty version, and that's different from the default.

Explicitly marking them with a version breaks kallsyms, so that
doesn't seem to be possible.

Marking all the symbols as local seems correct, and does seem
to address the issue, so do that. Also do it for static link,
nsswitch libraries could still be loaded there.

[1] https://bugs.debian.org/983379

Reported-by: Ritesh Raj Sarraf <rrs@debian.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Tested-By: Ritesh Raj Sarraf <rrs@debian.org>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Sasha Levin <sashal@kernel.org>
anthraxx pushed a commit that referenced this pull request May 25, 2021
[ Upstream commit d5027ca ]

Ritesh reported a bug [1] against UML, noting that it crashed on
startup. The backtrace shows the following (heavily redacted):

(gdb) bt
...
 #26 0x0000000060015b5d in sem_init () at ipc/sem.c:268
 #27 0x00007f89906d92f7 in ?? () from /lib/x86_64-linux-gnu/libcom_err.so.2
 #28 0x00007f8990ab8fb2 in call_init (...) at dl-init.c:72
...
 #40 0x00007f89909bf3a6 in nss_load_library (...) at nsswitch.c:359
...
 #44 0x00007f8990895e35 in _nss_compat_getgrnam_r (...) at nss_compat/compat-grp.c:486
 #45 0x00007f8990968b85 in __getgrnam_r [...]
 #46 0x00007f89909d6b77 in grantpt [...]
 #47 0x00007f8990a9394e in __GI_openpty [...]
 #48 0x00000000604a1f65 in openpty_cb (...) at arch/um/os-Linux/sigio.c:407
 #49 0x00000000604a58d0 in start_idle_thread (...) at arch/um/os-Linux/skas/process.c:598
 #50 0x0000000060004a3d in start_uml () at arch/um/kernel/skas/process.c:45
 #51 0x00000000600047b2 in linux_main (...) at arch/um/kernel/um_arch.c:334
 #52 0x000000006000574f in main (...) at arch/um/os-Linux/main.c:144

indicating that the UML function openpty_cb() calls openpty(),
which internally calls __getgrnam_r(), which causes the nsswitch
machinery to get started.

This loads, through lots of indirection that I snipped, the
libcom_err.so.2 library, which (in an unknown function, "??")
calls sem_init().

Now, of course it wants to get libpthread's sem_init(), since
it's linked against libpthread. However, the dynamic linker
looks up that symbol against the binary first, and gets the
kernel's sem_init().

Hajime Tazaki noted that "objcopy -L" can localize a symbol,
so the dynamic linker wouldn't do the lookup this way. I tried,
but for some reason that didn't seem to work.

Doing the same thing in the linker script instead does seem to
work, though I cannot entirely explain - it *also* works if I
just add "VERSION { { global: *; }; }" instead, indicating that
something else is happening that I don't really understand. It
may be that explicitly doing that marks them with some kind of
empty version, and that's different from the default.

Explicitly marking them with a version breaks kallsyms, so that
doesn't seem to be possible.

Marking all the symbols as local seems correct, and does seem
to address the issue, so do that. Also do it for static link,
nsswitch libraries could still be loaded there.

[1] https://bugs.debian.org/983379

Reported-by: Ritesh Raj Sarraf <rrs@debian.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Tested-By: Ritesh Raj Sarraf <rrs@debian.org>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Sasha Levin <sashal@kernel.org>
anthraxx pushed a commit that referenced this pull request Sep 23, 2021
[ Upstream commit b9edbfe ]

Commit 3df98d7 ("lsm,selinux: pass flowi_common instead of flowi
to the LSM hooks") introduced flowi{4,6}_to_flowi_common() functions which
cause UBSAN warning when building with LLVM 11.0.1 on Ubuntu 21.04.

 ================================================================================
 UBSAN: object-size-mismatch in ./include/net/flow.h:197:33
 member access within address ffffc9000109fbd8 with insufficient space
 for an object of type 'struct flowi'
 CPU: 2 PID: 7410 Comm: systemd-resolve Not tainted 5.14.0 #51
 Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 02/27/2020
 Call Trace:
  dump_stack_lvl+0x103/0x171
  ubsan_type_mismatch_common+0x1de/0x390
  __ubsan_handle_type_mismatch_v1+0x41/0x50
  udp_sendmsg+0xda2/0x1300
  ? ip_skb_dst_mtu+0x1f0/0x1f0
  ? sock_rps_record_flow+0xe/0x200
  ? inet_send_prepare+0x2d/0x90
  sock_sendmsg+0x49/0x80
  ____sys_sendmsg+0x269/0x370
  __sys_sendmsg+0x15e/0x1d0
  ? syscall_enter_from_user_mode+0xf0/0x1b0
  do_syscall_64+0x3d/0xb0
  entry_SYSCALL_64_after_hwframe+0x44/0xae
 RIP: 0033:0x7f7081a50497
 Code: 0c 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 89 54 24 1c 48 89 74 24 10
 RSP: 002b:00007ffc153870f8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
 RAX: ffffffffffffffda RBX: 000000000000000c RCX: 00007f7081a50497
 RDX: 0000000000000000 RSI: 00007ffc15387140 RDI: 000000000000000c
 RBP: 00007ffc15387140 R08: 0000563f29a5e4fc R09: 000000000000cd28
 R10: 0000563f29a68a30 R11: 0000000000000246 R12: 000000000000000c
 R13: 0000000000000001 R14: 0000563f29a68a30 R15: 0000563f29a5e50c
 ================================================================================

I don't think we need to call flowi{4,6}_to_flowi() from these functions
because the first member of "struct flowi4" and "struct flowi6" is

  struct flowi_common __fl_common;

while the first member of "struct flowi" is

  union {
    struct flowi_common __fl_common;
    struct flowi4       ip4;
    struct flowi6       ip6;
    struct flowidn      dn;
  } u;

which should point to the same address without access to "struct flowi".

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
anthraxx pushed a commit that referenced this pull request Feb 22, 2023
commit 27dada0 upstream.

The defer ops code has been finishing items in the wrong order -- if a
top level defer op creates items A and B, and finishing item A creates
more defer ops A1 and A2, we'll put the new items on the end of the
chain and process them in the order A B A1 A2.  This is kind of weird,
since it's convenient for programmers to be able to think of A and B as
an ordered sequence where all the sub-tasks for A must finish before we
move on to B, e.g. A A1 A2 D.

Right now, our log intent items are not so complex that this matters,
but this will become important for the atomic extent swapping patchset.
In order to maintain correct reference counting of extents, we have to
unmap and remap extents in that order, and we want to complete that work
before moving on to the next range that the user wants to swap.  This
patch fixes defer ops to satsify that requirement.

The primary symptom of the incorrect order was noticed in an early
performance analysis of the atomic extent swap code.  An astonishingly
large number of deferred work items accumulated when userspace requested
an atomic update of two very fragmented files.  The cause of this was
traced to the same ordering bug in the inner loop of
xfs_defer_finish_noroll.

If the ->finish_item method of a deferred operation queues new deferred
operations, those new deferred ops are appended to the tail of the
pending work list.  To illustrate, say that a caller creates a
transaction t0 with four deferred operations D0-D3.  The first thing
defer ops does is roll the transaction to t1, leaving us with:

t1: D0(t0), D1(t0), D2(t0), D3(t0)

Let's say that finishing each of D0-D3 will create two new deferred ops.
After finish D0 and roll, we'll have the following chain:

t2: D1(t0), D2(t0), D3(t0), d4(t1), d5(t1)

d4 and d5 were logged to t1.  Notice that while we're about to start
work on D1, we haven't actually completed all the work implied by D0
being finished.  So far we've been careful (or lucky) to structure the
dfops callers such that D1 doesn't depend on d4 or d5 being finished,
but this is a potential logic bomb.

There's a second problem lurking.  Let's see what happens as we finish
D1-D3:

t3: D2(t0), D3(t0), d4(t1), d5(t1), d6(t2), d7(t2)
t4: D3(t0), d4(t1), d5(t1), d6(t2), d7(t2), d8(t3), d9(t3)
t5: d4(t1), d5(t1), d6(t2), d7(t2), d8(t3), d9(t3), d10(t4), d11(t4)

Let's say that d4-d11 are simple work items that don't queue any other
operations, which means that we can complete each d4 and roll to t6:

t6: d5(t1), d6(t2), d7(t2), d8(t3), d9(t3), d10(t4), d11(t4)
t7: d6(t2), d7(t2), d8(t3), d9(t3), d10(t4), d11(t4)
...
t11: d10(t4), d11(t4)
t12: d11(t4)
<done>

When we try to roll to transaction #12, we're holding defer op d11,
which we logged way back in t4.  This means that the tail of the log is
pinned at t4.  If the log is very small or there are a lot of other
threads updating metadata, this means that we might have wrapped the log
and cannot get roll to t11 because there isn't enough space left before
we'd run into t4.

Let's shift back to the original failure.  I mentioned before that I
discovered this flaw while developing the atomic file update code.  In
that scenario, we have a defer op (D0) that finds a range of file blocks
to remap, creates a handful of new defer ops to do that, and then asks
to be continued with however much work remains.

So, D0 is the original swapext deferred op.  The first thing defer ops
does is rolls to t1:

t1: D0(t0)

We try to finish D0, logging d1 and d2 in the process, but can't get all
the work done.  We log a done item and a new intent item for the work
that D0 still has to do, and roll to t2:

t2: D0'(t1), d1(t1), d2(t1)

We roll and try to finish D0', but still can't get all the work done, so
we log a done item and a new intent item for it, requeue D0 a second
time, and roll to t3:

t3: D0''(t2), d1(t1), d2(t1), d3(t2), d4(t2)

If it takes 48 more rolls to complete D0, then we'll finally dispense
with D0 in t50:

t50: D<fifty primes>(t49), d1(t1), ..., d102(t50)

We then try to roll again to get a chain like this:

t51: d1(t1), d2(t1), ..., d101(t50), d102(t50)
...
t152: d102(t50)
<done>

Notice that in rolling to transaction #51, we're holding on to a log
intent item for d1 that was logged in transaction #1.  This means that
the tail of the log is pinned at t1.  If the log is very small or there
are a lot of other threads updating metadata, this means that we might
have wrapped the log and cannot roll to t51 because there isn't enough
space left before we'd run into t1.  This is of course problem #2 again.

But notice the third problem with this scenario: we have 102 defer ops
tied to this transaction!  Each of these items are backed by pinned
kernel memory, which means that we risk OOM if the chains get too long.

Yikes.  Problem #1 is a subtle logic bomb that could hit someone in the
future; problem #2 applies (rarely) to the current upstream, and problem

This is not how incremental deferred operations were supposed to work.
The dfops design of logging in the same transaction an intent-done item
and a new intent item for the work remaining was to make it so that we
only have to juggle enough deferred work items to finish that one small
piece of work.  Deferred log item recovery will find that first
unfinished work item and restart it, no matter how many other intent
items might follow it in the log.  Therefore, it's ok to put the new
intents at the start of the dfops chain.

For the first example, the chains look like this:

t2: d4(t1), d5(t1), D1(t0), D2(t0), D3(t0)
t3: d5(t1), D1(t0), D2(t0), D3(t0)
...
t9: d9(t7), D3(t0)
t10: D3(t0)
t11: d10(t10), d11(t10)
t12: d11(t10)

For the second example, the chains look like this:

t1: D0(t0)
t2: d1(t1), d2(t1), D0'(t1)
t3: d2(t1), D0'(t1)
t4: D0'(t1)
t5: d1(t4), d2(t4), D0''(t4)
...
t148: D0<50 primes>(t147)
t149: d101(t148), d102(t148)
t150: d102(t148)
<done>

This actually sucks more for pinning the log tail (we try to roll to t10
while holding an intent item that was logged in t1) but we've solved
problem #1.  We've also reduced the maximum chain length from:

    sum(all the new items) + nr_original_items

to:

    max(new items that each original item creates) + nr_original_items

This solves problem #3 by sharply reducing the number of defer ops that
can be attached to a transaction at any given time.  The change makes
the problem of log tail pinning worse, but is improvement we need to
solve problem #2.  Actually solving #2, however, is left to the next
patch.

Note that a subsequent analysis of some hard-to-trigger reflink and COW
livelocks on extremely fragmented filesystems (or systems running a lot
of IO threads) showed the same symptoms -- uncomfortably large numbers
of incore deferred work items and occasional stalls in the transaction
grant code while waiting for log reservations.  I think this patch and
the next one will also solve these problems.

As originally written, the code used list_splice_tail_init instead of
list_splice_init, so change that, and leave a short comment explaining
our actions.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Chandan Babu R <chandan.babu@oracle.com>
Acked-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
anthraxx pushed a commit that referenced this pull request Mar 26, 2023
[ Upstream commit b830c96 ]

ice_qp_dis() intends to stop a given queue pair that is a target of xsk
pool attach/detach. One of the steps is to disable interrupts on these
queues. It currently is broken in a way that txq irq is turned off
*after* HW flush which in turn takes no effect.

ice_qp_dis():
-> ice_qvec_dis_irq()
--> disable rxq irq
--> flush hw
-> ice_vsi_stop_tx_ring()
-->disable txq irq

Below splat can be triggered by following steps:
- start xdpsock WITHOUT loading xdp prog
- run xdp_rxq_info with XDP_TX action on this interface
- start traffic
- terminate xdpsock

[  256.312485] BUG: kernel NULL pointer dereference, address: 0000000000000018
[  256.319560] #PF: supervisor read access in kernel mode
[  256.324775] #PF: error_code(0x0000) - not-present page
[  256.329994] PGD 0 P4D 0
[  256.332574] Oops: 0000 [#1] PREEMPT SMP NOPTI
[  256.337006] CPU: 3 PID: 32 Comm: ksoftirqd/3 Tainted: G           OE      6.2.0-rc5+ #51
[  256.345218] Hardware name: Intel Corporation S2600WFT/S2600WFT, BIOS SE5C620.86B.02.01.0008.031920191559 03/19/2019
[  256.355807] RIP: 0010:ice_clean_rx_irq_zc+0x9c/0x7d0 [ice]
[  256.361423] Code: b7 8f 8a 00 00 00 66 39 ca 0f 84 f1 04 00 00 49 8b 47 40 4c 8b 24 d0 41 0f b7 45 04 66 25 ff 3f 66 89 04 24 0f 84 85 02 00 00 <49> 8b 44 24 18 0f b7 14 24 48 05 00 01 00 00 49 89 04 24 49 89 44
[  256.380463] RSP: 0018:ffffc900088bfd20 EFLAGS: 00010206
[  256.385765] RAX: 000000000000003c RBX: 0000000000000035 RCX: 000000000000067f
[  256.393012] RDX: 0000000000000775 RSI: 0000000000000000 RDI: ffff8881deb3ac80
[  256.400256] RBP: 000000000000003c R08: ffff889847982710 R09: 0000000000010000
[  256.407500] R10: ffffffff82c060c0 R11: 0000000000000004 R12: 0000000000000000
[  256.414746] R13: ffff88811165eea0 R14: ffffc9000d255000 R15: ffff888119b37600
[  256.421990] FS:  0000000000000000(0000) GS:ffff8897e0cc0000(0000) knlGS:0000000000000000
[  256.430207] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  256.436036] CR2: 0000000000000018 CR3: 0000000005c0a006 CR4: 00000000007706e0
[  256.443283] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  256.450527] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  256.457770] PKRU: 55555554
[  256.460529] Call Trace:
[  256.463015]  <TASK>
[  256.465157]  ? ice_xmit_zc+0x6e/0x150 [ice]
[  256.469437]  ice_napi_poll+0x46d/0x680 [ice]
[  256.473815]  ? _raw_spin_unlock_irqrestore+0x1b/0x40
[  256.478863]  __napi_poll+0x29/0x160
[  256.482409]  net_rx_action+0x136/0x260
[  256.486222]  __do_softirq+0xe8/0x2e5
[  256.489853]  ? smpboot_thread_fn+0x2c/0x270
[  256.494108]  run_ksoftirqd+0x2a/0x50
[  256.497747]  smpboot_thread_fn+0x1c1/0x270
[  256.501907]  ? __pfx_smpboot_thread_fn+0x10/0x10
[  256.506594]  kthread+0xea/0x120
[  256.509785]  ? __pfx_kthread+0x10/0x10
[  256.513597]  ret_from_fork+0x29/0x50
[  256.517238]  </TASK>

In fact, irqs were not disabled and napi managed to be scheduled and run
while xsk_pool pointer was still valid, but SW ring of xdp_buff pointers
was already freed.

To fix this, call ice_qvec_dis_irq() after ice_vsi_stop_tx_ring(). Also
while at it, remove redundant ice_clean_rx_ring() call - this is handled
in ice_qp_clean_rings().

Fixes: 2d4238f ("ice: Add support for AF_XDP")
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Reviewed-by: Larysa Zaremba <larysa.zaremba@intel.com>
Tested-by: Chandan Kumar Rout <chandanx.rout@intel.com> (A Contingent Worker at Intel)
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
anthraxx pushed a commit that referenced this pull request Mar 26, 2023
[ Upstream commit b830c96 ]

ice_qp_dis() intends to stop a given queue pair that is a target of xsk
pool attach/detach. One of the steps is to disable interrupts on these
queues. It currently is broken in a way that txq irq is turned off
*after* HW flush which in turn takes no effect.

ice_qp_dis():
-> ice_qvec_dis_irq()
--> disable rxq irq
--> flush hw
-> ice_vsi_stop_tx_ring()
-->disable txq irq

Below splat can be triggered by following steps:
- start xdpsock WITHOUT loading xdp prog
- run xdp_rxq_info with XDP_TX action on this interface
- start traffic
- terminate xdpsock

[  256.312485] BUG: kernel NULL pointer dereference, address: 0000000000000018
[  256.319560] #PF: supervisor read access in kernel mode
[  256.324775] #PF: error_code(0x0000) - not-present page
[  256.329994] PGD 0 P4D 0
[  256.332574] Oops: 0000 [#1] PREEMPT SMP NOPTI
[  256.337006] CPU: 3 PID: 32 Comm: ksoftirqd/3 Tainted: G           OE      6.2.0-rc5+ #51
[  256.345218] Hardware name: Intel Corporation S2600WFT/S2600WFT, BIOS SE5C620.86B.02.01.0008.031920191559 03/19/2019
[  256.355807] RIP: 0010:ice_clean_rx_irq_zc+0x9c/0x7d0 [ice]
[  256.361423] Code: b7 8f 8a 00 00 00 66 39 ca 0f 84 f1 04 00 00 49 8b 47 40 4c 8b 24 d0 41 0f b7 45 04 66 25 ff 3f 66 89 04 24 0f 84 85 02 00 00 <49> 8b 44 24 18 0f b7 14 24 48 05 00 01 00 00 49 89 04 24 49 89 44
[  256.380463] RSP: 0018:ffffc900088bfd20 EFLAGS: 00010206
[  256.385765] RAX: 000000000000003c RBX: 0000000000000035 RCX: 000000000000067f
[  256.393012] RDX: 0000000000000775 RSI: 0000000000000000 RDI: ffff8881deb3ac80
[  256.400256] RBP: 000000000000003c R08: ffff889847982710 R09: 0000000000010000
[  256.407500] R10: ffffffff82c060c0 R11: 0000000000000004 R12: 0000000000000000
[  256.414746] R13: ffff88811165eea0 R14: ffffc9000d255000 R15: ffff888119b37600
[  256.421990] FS:  0000000000000000(0000) GS:ffff8897e0cc0000(0000) knlGS:0000000000000000
[  256.430207] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  256.436036] CR2: 0000000000000018 CR3: 0000000005c0a006 CR4: 00000000007706e0
[  256.443283] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  256.450527] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  256.457770] PKRU: 55555554
[  256.460529] Call Trace:
[  256.463015]  <TASK>
[  256.465157]  ? ice_xmit_zc+0x6e/0x150 [ice]
[  256.469437]  ice_napi_poll+0x46d/0x680 [ice]
[  256.473815]  ? _raw_spin_unlock_irqrestore+0x1b/0x40
[  256.478863]  __napi_poll+0x29/0x160
[  256.482409]  net_rx_action+0x136/0x260
[  256.486222]  __do_softirq+0xe8/0x2e5
[  256.489853]  ? smpboot_thread_fn+0x2c/0x270
[  256.494108]  run_ksoftirqd+0x2a/0x50
[  256.497747]  smpboot_thread_fn+0x1c1/0x270
[  256.501907]  ? __pfx_smpboot_thread_fn+0x10/0x10
[  256.506594]  kthread+0xea/0x120
[  256.509785]  ? __pfx_kthread+0x10/0x10
[  256.513597]  ret_from_fork+0x29/0x50
[  256.517238]  </TASK>

In fact, irqs were not disabled and napi managed to be scheduled and run
while xsk_pool pointer was still valid, but SW ring of xdp_buff pointers
was already freed.

To fix this, call ice_qvec_dis_irq() after ice_vsi_stop_tx_ring(). Also
while at it, remove redundant ice_clean_rx_ring() call - this is handled
in ice_qp_clean_rings().

Fixes: 2d4238f ("ice: Add support for AF_XDP")
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Reviewed-by: Larysa Zaremba <larysa.zaremba@intel.com>
Tested-by: Chandan Kumar Rout <chandanx.rout@intel.com> (A Contingent Worker at Intel)
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
anthraxx pushed a commit that referenced this pull request Mar 26, 2023
[ Upstream commit b830c96 ]

ice_qp_dis() intends to stop a given queue pair that is a target of xsk
pool attach/detach. One of the steps is to disable interrupts on these
queues. It currently is broken in a way that txq irq is turned off
*after* HW flush which in turn takes no effect.

ice_qp_dis():
-> ice_qvec_dis_irq()
--> disable rxq irq
--> flush hw
-> ice_vsi_stop_tx_ring()
-->disable txq irq

Below splat can be triggered by following steps:
- start xdpsock WITHOUT loading xdp prog
- run xdp_rxq_info with XDP_TX action on this interface
- start traffic
- terminate xdpsock

[  256.312485] BUG: kernel NULL pointer dereference, address: 0000000000000018
[  256.319560] #PF: supervisor read access in kernel mode
[  256.324775] #PF: error_code(0x0000) - not-present page
[  256.329994] PGD 0 P4D 0
[  256.332574] Oops: 0000 [#1] PREEMPT SMP NOPTI
[  256.337006] CPU: 3 PID: 32 Comm: ksoftirqd/3 Tainted: G           OE      6.2.0-rc5+ #51
[  256.345218] Hardware name: Intel Corporation S2600WFT/S2600WFT, BIOS SE5C620.86B.02.01.0008.031920191559 03/19/2019
[  256.355807] RIP: 0010:ice_clean_rx_irq_zc+0x9c/0x7d0 [ice]
[  256.361423] Code: b7 8f 8a 00 00 00 66 39 ca 0f 84 f1 04 00 00 49 8b 47 40 4c 8b 24 d0 41 0f b7 45 04 66 25 ff 3f 66 89 04 24 0f 84 85 02 00 00 <49> 8b 44 24 18 0f b7 14 24 48 05 00 01 00 00 49 89 04 24 49 89 44
[  256.380463] RSP: 0018:ffffc900088bfd20 EFLAGS: 00010206
[  256.385765] RAX: 000000000000003c RBX: 0000000000000035 RCX: 000000000000067f
[  256.393012] RDX: 0000000000000775 RSI: 0000000000000000 RDI: ffff8881deb3ac80
[  256.400256] RBP: 000000000000003c R08: ffff889847982710 R09: 0000000000010000
[  256.407500] R10: ffffffff82c060c0 R11: 0000000000000004 R12: 0000000000000000
[  256.414746] R13: ffff88811165eea0 R14: ffffc9000d255000 R15: ffff888119b37600
[  256.421990] FS:  0000000000000000(0000) GS:ffff8897e0cc0000(0000) knlGS:0000000000000000
[  256.430207] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  256.436036] CR2: 0000000000000018 CR3: 0000000005c0a006 CR4: 00000000007706e0
[  256.443283] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  256.450527] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  256.457770] PKRU: 55555554
[  256.460529] Call Trace:
[  256.463015]  <TASK>
[  256.465157]  ? ice_xmit_zc+0x6e/0x150 [ice]
[  256.469437]  ice_napi_poll+0x46d/0x680 [ice]
[  256.473815]  ? _raw_spin_unlock_irqrestore+0x1b/0x40
[  256.478863]  __napi_poll+0x29/0x160
[  256.482409]  net_rx_action+0x136/0x260
[  256.486222]  __do_softirq+0xe8/0x2e5
[  256.489853]  ? smpboot_thread_fn+0x2c/0x270
[  256.494108]  run_ksoftirqd+0x2a/0x50
[  256.497747]  smpboot_thread_fn+0x1c1/0x270
[  256.501907]  ? __pfx_smpboot_thread_fn+0x10/0x10
[  256.506594]  kthread+0xea/0x120
[  256.509785]  ? __pfx_kthread+0x10/0x10
[  256.513597]  ret_from_fork+0x29/0x50
[  256.517238]  </TASK>

In fact, irqs were not disabled and napi managed to be scheduled and run
while xsk_pool pointer was still valid, but SW ring of xdp_buff pointers
was already freed.

To fix this, call ice_qvec_dis_irq() after ice_vsi_stop_tx_ring(). Also
while at it, remove redundant ice_clean_rx_ring() call - this is handled
in ice_qp_clean_rings().

Fixes: 2d4238f ("ice: Add support for AF_XDP")
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Reviewed-by: Larysa Zaremba <larysa.zaremba@intel.com>
Tested-by: Chandan Kumar Rout <chandanx.rout@intel.com> (A Contingent Worker at Intel)
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
anthraxx pushed a commit that referenced this pull request Jun 27, 2023
[ Upstream commit b830c96 ]

ice_qp_dis() intends to stop a given queue pair that is a target of xsk
pool attach/detach. One of the steps is to disable interrupts on these
queues. It currently is broken in a way that txq irq is turned off
*after* HW flush which in turn takes no effect.

ice_qp_dis():
-> ice_qvec_dis_irq()
--> disable rxq irq
--> flush hw
-> ice_vsi_stop_tx_ring()
-->disable txq irq

Below splat can be triggered by following steps:
- start xdpsock WITHOUT loading xdp prog
- run xdp_rxq_info with XDP_TX action on this interface
- start traffic
- terminate xdpsock

[  256.312485] BUG: kernel NULL pointer dereference, address: 0000000000000018
[  256.319560] #PF: supervisor read access in kernel mode
[  256.324775] #PF: error_code(0x0000) - not-present page
[  256.329994] PGD 0 P4D 0
[  256.332574] Oops: 0000 [#1] PREEMPT SMP NOPTI
[  256.337006] CPU: 3 PID: 32 Comm: ksoftirqd/3 Tainted: G           OE      6.2.0-rc5+ #51
[  256.345218] Hardware name: Intel Corporation S2600WFT/S2600WFT, BIOS SE5C620.86B.02.01.0008.031920191559 03/19/2019
[  256.355807] RIP: 0010:ice_clean_rx_irq_zc+0x9c/0x7d0 [ice]
[  256.361423] Code: b7 8f 8a 00 00 00 66 39 ca 0f 84 f1 04 00 00 49 8b 47 40 4c 8b 24 d0 41 0f b7 45 04 66 25 ff 3f 66 89 04 24 0f 84 85 02 00 00 <49> 8b 44 24 18 0f b7 14 24 48 05 00 01 00 00 49 89 04 24 49 89 44
[  256.380463] RSP: 0018:ffffc900088bfd20 EFLAGS: 00010206
[  256.385765] RAX: 000000000000003c RBX: 0000000000000035 RCX: 000000000000067f
[  256.393012] RDX: 0000000000000775 RSI: 0000000000000000 RDI: ffff8881deb3ac80
[  256.400256] RBP: 000000000000003c R08: ffff889847982710 R09: 0000000000010000
[  256.407500] R10: ffffffff82c060c0 R11: 0000000000000004 R12: 0000000000000000
[  256.414746] R13: ffff88811165eea0 R14: ffffc9000d255000 R15: ffff888119b37600
[  256.421990] FS:  0000000000000000(0000) GS:ffff8897e0cc0000(0000) knlGS:0000000000000000
[  256.430207] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  256.436036] CR2: 0000000000000018 CR3: 0000000005c0a006 CR4: 00000000007706e0
[  256.443283] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  256.450527] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  256.457770] PKRU: 55555554
[  256.460529] Call Trace:
[  256.463015]  <TASK>
[  256.465157]  ? ice_xmit_zc+0x6e/0x150 [ice]
[  256.469437]  ice_napi_poll+0x46d/0x680 [ice]
[  256.473815]  ? _raw_spin_unlock_irqrestore+0x1b/0x40
[  256.478863]  __napi_poll+0x29/0x160
[  256.482409]  net_rx_action+0x136/0x260
[  256.486222]  __do_softirq+0xe8/0x2e5
[  256.489853]  ? smpboot_thread_fn+0x2c/0x270
[  256.494108]  run_ksoftirqd+0x2a/0x50
[  256.497747]  smpboot_thread_fn+0x1c1/0x270
[  256.501907]  ? __pfx_smpboot_thread_fn+0x10/0x10
[  256.506594]  kthread+0xea/0x120
[  256.509785]  ? __pfx_kthread+0x10/0x10
[  256.513597]  ret_from_fork+0x29/0x50
[  256.517238]  </TASK>

In fact, irqs were not disabled and napi managed to be scheduled and run
while xsk_pool pointer was still valid, but SW ring of xdp_buff pointers
was already freed.

To fix this, call ice_qvec_dis_irq() after ice_vsi_stop_tx_ring(). Also
while at it, remove redundant ice_clean_rx_ring() call - this is handled
in ice_qp_clean_rings().

Fixes: 2d4238f ("ice: Add support for AF_XDP")
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Reviewed-by: Larysa Zaremba <larysa.zaremba@intel.com>
Tested-by: Chandan Kumar Rout <chandanx.rout@intel.com> (A Contingent Worker at Intel)
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
anthraxx pushed a commit that referenced this pull request Dec 13, 2023
[ Upstream commit 5d47ec2 ]

The `cls_redirect` test triggers a kernel panic like:

  # ./test_progs -t cls_redirect
  Can't find bpf_testmod.ko kernel module: -2
  WARNING! Selftests relying on bpf_testmod.ko will be skipped.
  [   30.938489] CPU 3 Unable to handle kernel paging request at virtual address fffffffffd814de0, era == ffff800002009fb8, ra == ffff800002009f9c
  [   30.939331] Oops[#1]:
  [   30.939513] CPU: 3 PID: 1260 Comm: test_progs Not tainted 6.7.0-rc2-loong-devel-g2f56bb0d2327 #35 a896aca3f4164f09cc346f89f2e09832e07be5f6
  [   30.939732] Hardware name: QEMU QEMU Virtual Machine, BIOS unknown 2/2/2022
  [   30.939901] pc ffff800002009fb8 ra ffff800002009f9c tp 9000000104da4000 sp 9000000104da7ab0
  [   30.940038] a0 fffffffffd814de0 a1 9000000104da7a68 a2 0000000000000000 a3 9000000104da7c10
  [   30.940183] a4 9000000104da7c14 a5 0000000000000002 a6 0000000000000021 a7 00005555904d7f90
  [   30.940321] t0 0000000000000110 t1 0000000000000000 t2 fffffffffd814de0 t3 0004c4b400000000
  [   30.940456] t4 ffffffffffffffff t5 00000000c3f63600 t6 0000000000000000 t7 0000000000000000
  [   30.940590] t8 000000000006d803 u0 0000000000000020 s9 9000000104da7b10 s0 900000010504c200
  [   30.940727] s1 fffffffffd814de0 s2 900000010504c200 s3 9000000104da7c10 s4 9000000104da7ad0
  [   30.940866] s5 0000000000000000 s6 90000000030e65bc s7 9000000104da7b44 s8 90000000044f6fc0
  [   30.941015]    ra: ffff800002009f9c bpf_prog_846803e5ae81417f_cls_redirect+0xa0/0x590
  [   30.941535]   ERA: ffff800002009fb8 bpf_prog_846803e5ae81417f_cls_redirect+0xbc/0x590
  [   30.941696]  CRMD: 000000b0 (PLV0 -IE -DA +PG DACF=CC DACM=CC -WE)
  [   30.942224]  PRMD: 00000004 (PPLV0 +PIE -PWE)
  [   30.942330]  EUEN: 00000003 (+FPE +SXE -ASXE -BTE)
  [   30.942453]  ECFG: 00071c1c (LIE=2-4,10-12 VS=7)
  [   30.942612] ESTAT: 00010000 [PIL] (IS= ECode=1 EsubCode=0)
  [   30.942764]  BADV: fffffffffd814de0
  [   30.942854]  PRID: 0014c010 (Loongson-64bit, Loongson-3A5000)
  [   30.942974] Modules linked in:
  [   30.943078] Process test_progs (pid: 1260, threadinfo=00000000ce303226, task=000000007d10bb76)
  [   30.943306] Stack : 900000010a064000 90000000044f6fc0 9000000104da7b48 0000000000000000
  [   30.943495]         0000000000000000 9000000104da7c14 9000000104da7c10 900000010504c200
  [   30.943626]         0000000000000001 ffff80001b88c000 9000000104da7b70 90000000030e6668
  [   30.943785]         0000000000000000 9000000104da7b58 ffff80001b88c048 9000000003d05000
  [   30.943936]         900000000303ac88 0000000000000000 0000000000000000 9000000104da7b70
  [   30.944091]         0000000000000000 0000000000000001 0000000731eeab00 0000000000000000
  [   30.944245]         ffff80001b88c000 0000000000000000 0000000000000000 54b99959429f83b8
  [   30.944402]         ffff80001b88c000 90000000044f6fc0 9000000101d70000 ffff80001b88c000
  [   30.944538]         000000000000005a 900000010504c200 900000010a064000 900000010a067000
  [   30.944697]         9000000104da7d88 0000000000000000 9000000003d05000 90000000030e794c
  [   30.944852]         ...
  [   30.944924] Call Trace:
  [   30.945120] [<ffff800002009fb8>] bpf_prog_846803e5ae81417f_cls_redirect+0xbc/0x590
  [   30.945650] [<90000000030e6668>] bpf_test_run+0x1ec/0x2f8
  [   30.945958] [<90000000030e794c>] bpf_prog_test_run_skb+0x31c/0x684
  [   30.946065] [<90000000026d4f68>] __sys_bpf+0x678/0x2724
  [   30.946159] [<90000000026d7288>] sys_bpf+0x20/0x2c
  [   30.946253] [<90000000032dd224>] do_syscall+0x7c/0x94
  [   30.946343] [<9000000002541c5c>] handle_syscall+0xbc/0x158
  [   30.946492]
  [   30.946549] Code: 0015030e  5c0009c0  5001d000 <28c00304> 02c00484  29c00304  00150009  2a42d2e4  0280200d
  [   30.946793]
  [   30.946971] ---[ end trace 0000000000000000 ]---
  [   32.093225] Kernel panic - not syncing: Fatal exception in interrupt
  [   32.093526] Kernel relocated by 0x2320000
  [   32.093630]  .text @ 0x9000000002520000
  [   32.093725]  .data @ 0x9000000003400000
  [   32.093792]  .bss  @ 0x9000000004413200
  [   34.971998] ---[ end Kernel panic - not syncing: Fatal exception in interrupt ]---

This is because we signed-extend function return values. When subprog
mode is enabled, we have:

  cls_redirect()
    -> get_global_metrics() returns pcpu ptr 0xfffffefffc00b480

The pointer returned is later signed-extended to 0xfffffffffc00b480 at
`BPF_JMP | BPF_EXIT`. During BPF prog run, this triggers unhandled page
fault and a kernel panic.

Drop the unnecessary signed-extension on return values like other
architectures do.

With this change, we have:

  # ./test_progs -t cls_redirect
  Can't find bpf_testmod.ko kernel module: -2
  WARNING! Selftests relying on bpf_testmod.ko will be skipped.
  #51/1    cls_redirect/cls_redirect_inlined:OK
  #51/2    cls_redirect/IPv4 TCP accept unknown (no hops, flags: SYN):OK
  #51/3    cls_redirect/IPv6 TCP accept unknown (no hops, flags: SYN):OK
  #51/4    cls_redirect/IPv4 TCP accept unknown (no hops, flags: ACK):OK
  #51/5    cls_redirect/IPv6 TCP accept unknown (no hops, flags: ACK):OK
  #51/6    cls_redirect/IPv4 TCP forward unknown (one hop, flags: ACK):OK
  #51/7    cls_redirect/IPv6 TCP forward unknown (one hop, flags: ACK):OK
  #51/8    cls_redirect/IPv4 TCP accept known (one hop, flags: ACK):OK
  #51/9    cls_redirect/IPv6 TCP accept known (one hop, flags: ACK):OK
  #51/10   cls_redirect/IPv4 UDP accept unknown (no hops, flags: none):OK
  #51/11   cls_redirect/IPv6 UDP accept unknown (no hops, flags: none):OK
  #51/12   cls_redirect/IPv4 UDP forward unknown (one hop, flags: none):OK
  #51/13   cls_redirect/IPv6 UDP forward unknown (one hop, flags: none):OK
  #51/14   cls_redirect/IPv4 UDP accept known (one hop, flags: none):OK
  #51/15   cls_redirect/IPv6 UDP accept known (one hop, flags: none):OK
  #51/16   cls_redirect/cls_redirect_subprogs:OK
  #51/17   cls_redirect/IPv4 TCP accept unknown (no hops, flags: SYN):OK
  #51/18   cls_redirect/IPv6 TCP accept unknown (no hops, flags: SYN):OK
  #51/19   cls_redirect/IPv4 TCP accept unknown (no hops, flags: ACK):OK
  #51/20   cls_redirect/IPv6 TCP accept unknown (no hops, flags: ACK):OK
  #51/21   cls_redirect/IPv4 TCP forward unknown (one hop, flags: ACK):OK
  #51/22   cls_redirect/IPv6 TCP forward unknown (one hop, flags: ACK):OK
  #51/23   cls_redirect/IPv4 TCP accept known (one hop, flags: ACK):OK
  #51/24   cls_redirect/IPv6 TCP accept known (one hop, flags: ACK):OK
  #51/25   cls_redirect/IPv4 UDP accept unknown (no hops, flags: none):OK
  #51/26   cls_redirect/IPv6 UDP accept unknown (no hops, flags: none):OK
  #51/27   cls_redirect/IPv4 UDP forward unknown (one hop, flags: none):OK
  #51/28   cls_redirect/IPv6 UDP forward unknown (one hop, flags: none):OK
  #51/29   cls_redirect/IPv4 UDP accept known (one hop, flags: none):OK
  #51/30   cls_redirect/IPv6 UDP accept known (one hop, flags: none):OK
  #51/31   cls_redirect/cls_redirect_dynptr:OK
  #51/32   cls_redirect/IPv4 TCP accept unknown (no hops, flags: SYN):OK
  #51/33   cls_redirect/IPv6 TCP accept unknown (no hops, flags: SYN):OK
  #51/34   cls_redirect/IPv4 TCP accept unknown (no hops, flags: ACK):OK
  #51/35   cls_redirect/IPv6 TCP accept unknown (no hops, flags: ACK):OK
  #51/36   cls_redirect/IPv4 TCP forward unknown (one hop, flags: ACK):OK
  #51/37   cls_redirect/IPv6 TCP forward unknown (one hop, flags: ACK):OK
  #51/38   cls_redirect/IPv4 TCP accept known (one hop, flags: ACK):OK
  #51/39   cls_redirect/IPv6 TCP accept known (one hop, flags: ACK):OK
  #51/40   cls_redirect/IPv4 UDP accept unknown (no hops, flags: none):OK
  #51/41   cls_redirect/IPv6 UDP accept unknown (no hops, flags: none):OK
  #51/42   cls_redirect/IPv4 UDP forward unknown (one hop, flags: none):OK
  #51/43   cls_redirect/IPv6 UDP forward unknown (one hop, flags: none):OK
  #51/44   cls_redirect/IPv4 UDP accept known (one hop, flags: none):OK
  #51/45   cls_redirect/IPv6 UDP accept known (one hop, flags: none):OK
  #51      cls_redirect:OK
  Summary: 1/45 PASSED, 0 SKIPPED, 0 FAILED

Fixes: 5dc6155 ("LoongArch: Add BPF JIT support")
Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Sasha Levin <sashal@kernel.org>
anthraxx pushed a commit that referenced this pull request Dec 13, 2023
[ Upstream commit 5d47ec2 ]

The `cls_redirect` test triggers a kernel panic like:

  # ./test_progs -t cls_redirect
  Can't find bpf_testmod.ko kernel module: -2
  WARNING! Selftests relying on bpf_testmod.ko will be skipped.
  [   30.938489] CPU 3 Unable to handle kernel paging request at virtual address fffffffffd814de0, era == ffff800002009fb8, ra == ffff800002009f9c
  [   30.939331] Oops[#1]:
  [   30.939513] CPU: 3 PID: 1260 Comm: test_progs Not tainted 6.7.0-rc2-loong-devel-g2f56bb0d2327 #35 a896aca3f4164f09cc346f89f2e09832e07be5f6
  [   30.939732] Hardware name: QEMU QEMU Virtual Machine, BIOS unknown 2/2/2022
  [   30.939901] pc ffff800002009fb8 ra ffff800002009f9c tp 9000000104da4000 sp 9000000104da7ab0
  [   30.940038] a0 fffffffffd814de0 a1 9000000104da7a68 a2 0000000000000000 a3 9000000104da7c10
  [   30.940183] a4 9000000104da7c14 a5 0000000000000002 a6 0000000000000021 a7 00005555904d7f90
  [   30.940321] t0 0000000000000110 t1 0000000000000000 t2 fffffffffd814de0 t3 0004c4b400000000
  [   30.940456] t4 ffffffffffffffff t5 00000000c3f63600 t6 0000000000000000 t7 0000000000000000
  [   30.940590] t8 000000000006d803 u0 0000000000000020 s9 9000000104da7b10 s0 900000010504c200
  [   30.940727] s1 fffffffffd814de0 s2 900000010504c200 s3 9000000104da7c10 s4 9000000104da7ad0
  [   30.940866] s5 0000000000000000 s6 90000000030e65bc s7 9000000104da7b44 s8 90000000044f6fc0
  [   30.941015]    ra: ffff800002009f9c bpf_prog_846803e5ae81417f_cls_redirect+0xa0/0x590
  [   30.941535]   ERA: ffff800002009fb8 bpf_prog_846803e5ae81417f_cls_redirect+0xbc/0x590
  [   30.941696]  CRMD: 000000b0 (PLV0 -IE -DA +PG DACF=CC DACM=CC -WE)
  [   30.942224]  PRMD: 00000004 (PPLV0 +PIE -PWE)
  [   30.942330]  EUEN: 00000003 (+FPE +SXE -ASXE -BTE)
  [   30.942453]  ECFG: 00071c1c (LIE=2-4,10-12 VS=7)
  [   30.942612] ESTAT: 00010000 [PIL] (IS= ECode=1 EsubCode=0)
  [   30.942764]  BADV: fffffffffd814de0
  [   30.942854]  PRID: 0014c010 (Loongson-64bit, Loongson-3A5000)
  [   30.942974] Modules linked in:
  [   30.943078] Process test_progs (pid: 1260, threadinfo=00000000ce303226, task=000000007d10bb76)
  [   30.943306] Stack : 900000010a064000 90000000044f6fc0 9000000104da7b48 0000000000000000
  [   30.943495]         0000000000000000 9000000104da7c14 9000000104da7c10 900000010504c200
  [   30.943626]         0000000000000001 ffff80001b88c000 9000000104da7b70 90000000030e6668
  [   30.943785]         0000000000000000 9000000104da7b58 ffff80001b88c048 9000000003d05000
  [   30.943936]         900000000303ac88 0000000000000000 0000000000000000 9000000104da7b70
  [   30.944091]         0000000000000000 0000000000000001 0000000731eeab00 0000000000000000
  [   30.944245]         ffff80001b88c000 0000000000000000 0000000000000000 54b99959429f83b8
  [   30.944402]         ffff80001b88c000 90000000044f6fc0 9000000101d70000 ffff80001b88c000
  [   30.944538]         000000000000005a 900000010504c200 900000010a064000 900000010a067000
  [   30.944697]         9000000104da7d88 0000000000000000 9000000003d05000 90000000030e794c
  [   30.944852]         ...
  [   30.944924] Call Trace:
  [   30.945120] [<ffff800002009fb8>] bpf_prog_846803e5ae81417f_cls_redirect+0xbc/0x590
  [   30.945650] [<90000000030e6668>] bpf_test_run+0x1ec/0x2f8
  [   30.945958] [<90000000030e794c>] bpf_prog_test_run_skb+0x31c/0x684
  [   30.946065] [<90000000026d4f68>] __sys_bpf+0x678/0x2724
  [   30.946159] [<90000000026d7288>] sys_bpf+0x20/0x2c
  [   30.946253] [<90000000032dd224>] do_syscall+0x7c/0x94
  [   30.946343] [<9000000002541c5c>] handle_syscall+0xbc/0x158
  [   30.946492]
  [   30.946549] Code: 0015030e  5c0009c0  5001d000 <28c00304> 02c00484  29c00304  00150009  2a42d2e4  0280200d
  [   30.946793]
  [   30.946971] ---[ end trace 0000000000000000 ]---
  [   32.093225] Kernel panic - not syncing: Fatal exception in interrupt
  [   32.093526] Kernel relocated by 0x2320000
  [   32.093630]  .text @ 0x9000000002520000
  [   32.093725]  .data @ 0x9000000003400000
  [   32.093792]  .bss  @ 0x9000000004413200
  [   34.971998] ---[ end Kernel panic - not syncing: Fatal exception in interrupt ]---

This is because we signed-extend function return values. When subprog
mode is enabled, we have:

  cls_redirect()
    -> get_global_metrics() returns pcpu ptr 0xfffffefffc00b480

The pointer returned is later signed-extended to 0xfffffffffc00b480 at
`BPF_JMP | BPF_EXIT`. During BPF prog run, this triggers unhandled page
fault and a kernel panic.

Drop the unnecessary signed-extension on return values like other
architectures do.

With this change, we have:

  # ./test_progs -t cls_redirect
  Can't find bpf_testmod.ko kernel module: -2
  WARNING! Selftests relying on bpf_testmod.ko will be skipped.
  #51/1    cls_redirect/cls_redirect_inlined:OK
  #51/2    cls_redirect/IPv4 TCP accept unknown (no hops, flags: SYN):OK
  #51/3    cls_redirect/IPv6 TCP accept unknown (no hops, flags: SYN):OK
  #51/4    cls_redirect/IPv4 TCP accept unknown (no hops, flags: ACK):OK
  #51/5    cls_redirect/IPv6 TCP accept unknown (no hops, flags: ACK):OK
  #51/6    cls_redirect/IPv4 TCP forward unknown (one hop, flags: ACK):OK
  #51/7    cls_redirect/IPv6 TCP forward unknown (one hop, flags: ACK):OK
  #51/8    cls_redirect/IPv4 TCP accept known (one hop, flags: ACK):OK
  #51/9    cls_redirect/IPv6 TCP accept known (one hop, flags: ACK):OK
  #51/10   cls_redirect/IPv4 UDP accept unknown (no hops, flags: none):OK
  #51/11   cls_redirect/IPv6 UDP accept unknown (no hops, flags: none):OK
  #51/12   cls_redirect/IPv4 UDP forward unknown (one hop, flags: none):OK
  #51/13   cls_redirect/IPv6 UDP forward unknown (one hop, flags: none):OK
  #51/14   cls_redirect/IPv4 UDP accept known (one hop, flags: none):OK
  #51/15   cls_redirect/IPv6 UDP accept known (one hop, flags: none):OK
  #51/16   cls_redirect/cls_redirect_subprogs:OK
  #51/17   cls_redirect/IPv4 TCP accept unknown (no hops, flags: SYN):OK
  #51/18   cls_redirect/IPv6 TCP accept unknown (no hops, flags: SYN):OK
  #51/19   cls_redirect/IPv4 TCP accept unknown (no hops, flags: ACK):OK
  #51/20   cls_redirect/IPv6 TCP accept unknown (no hops, flags: ACK):OK
  #51/21   cls_redirect/IPv4 TCP forward unknown (one hop, flags: ACK):OK
  #51/22   cls_redirect/IPv6 TCP forward unknown (one hop, flags: ACK):OK
  #51/23   cls_redirect/IPv4 TCP accept known (one hop, flags: ACK):OK
  #51/24   cls_redirect/IPv6 TCP accept known (one hop, flags: ACK):OK
  #51/25   cls_redirect/IPv4 UDP accept unknown (no hops, flags: none):OK
  #51/26   cls_redirect/IPv6 UDP accept unknown (no hops, flags: none):OK
  #51/27   cls_redirect/IPv4 UDP forward unknown (one hop, flags: none):OK
  #51/28   cls_redirect/IPv6 UDP forward unknown (one hop, flags: none):OK
  #51/29   cls_redirect/IPv4 UDP accept known (one hop, flags: none):OK
  #51/30   cls_redirect/IPv6 UDP accept known (one hop, flags: none):OK
  #51/31   cls_redirect/cls_redirect_dynptr:OK
  #51/32   cls_redirect/IPv4 TCP accept unknown (no hops, flags: SYN):OK
  #51/33   cls_redirect/IPv6 TCP accept unknown (no hops, flags: SYN):OK
  #51/34   cls_redirect/IPv4 TCP accept unknown (no hops, flags: ACK):OK
  #51/35   cls_redirect/IPv6 TCP accept unknown (no hops, flags: ACK):OK
  #51/36   cls_redirect/IPv4 TCP forward unknown (one hop, flags: ACK):OK
  #51/37   cls_redirect/IPv6 TCP forward unknown (one hop, flags: ACK):OK
  #51/38   cls_redirect/IPv4 TCP accept known (one hop, flags: ACK):OK
  #51/39   cls_redirect/IPv6 TCP accept known (one hop, flags: ACK):OK
  #51/40   cls_redirect/IPv4 UDP accept unknown (no hops, flags: none):OK
  #51/41   cls_redirect/IPv6 UDP accept unknown (no hops, flags: none):OK
  #51/42   cls_redirect/IPv4 UDP forward unknown (one hop, flags: none):OK
  #51/43   cls_redirect/IPv6 UDP forward unknown (one hop, flags: none):OK
  #51/44   cls_redirect/IPv4 UDP accept known (one hop, flags: none):OK
  #51/45   cls_redirect/IPv6 UDP accept known (one hop, flags: none):OK
  #51      cls_redirect:OK
  Summary: 1/45 PASSED, 0 SKIPPED, 0 FAILED

Fixes: 5dc6155 ("LoongArch: Add BPF JIT support")
Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Sasha Levin <sashal@kernel.org>
anthraxx pushed a commit that referenced this pull request Jan 10, 2024
[ Upstream commit 9dbe086 ]

A crash was found when dumping SMC-R connections. It can be reproduced
by following steps:

- environment: two RNICs on both sides.
- run SMC-R between two sides, now a SMC_LGR_SYMMETRIC type link group
  will be created.
- set the first RNIC down on either side and link group will turn to
  SMC_LGR_ASYMMETRIC_LOCAL then.
- run 'smcss -R' and the crash will be triggered.

 BUG: kernel NULL pointer dereference, address: 0000000000000010
 #PF: supervisor read access in kernel mode
 #PF: error_code(0x0000) - not-present page
 PGD 8000000101fdd067 P4D 8000000101fdd067 PUD 10ce46067 PMD 0
 Oops: 0000 [#1] PREEMPT SMP PTI
 CPU: 3 PID: 1810 Comm: smcss Kdump: loaded Tainted: G W   E      6.7.0-rc6+ #51
 RIP: 0010:__smc_diag_dump.constprop.0+0x36e/0x620 [smc_diag]
 Call Trace:
  <TASK>
  ? __die+0x24/0x70
  ? page_fault_oops+0x66/0x150
  ? exc_page_fault+0x69/0x140
  ? asm_exc_page_fault+0x26/0x30
  ? __smc_diag_dump.constprop.0+0x36e/0x620 [smc_diag]
  smc_diag_dump_proto+0xd0/0xf0 [smc_diag]
  smc_diag_dump+0x26/0x60 [smc_diag]
  netlink_dump+0x19f/0x320
  __netlink_dump_start+0x1dc/0x300
  smc_diag_handler_dump+0x6a/0x80 [smc_diag]
  ? __pfx_smc_diag_dump+0x10/0x10 [smc_diag]
  sock_diag_rcv_msg+0x121/0x140
  ? __pfx_sock_diag_rcv_msg+0x10/0x10
  netlink_rcv_skb+0x5a/0x110
  sock_diag_rcv+0x28/0x40
  netlink_unicast+0x22a/0x330
  netlink_sendmsg+0x240/0x4a0
  __sock_sendmsg+0xb0/0xc0
  ____sys_sendmsg+0x24e/0x300
  ? copy_msghdr_from_user+0x62/0x80
  ___sys_sendmsg+0x7c/0xd0
  ? __do_fault+0x34/0x1a0
  ? do_read_fault+0x5f/0x100
  ? do_fault+0xb0/0x110
  __sys_sendmsg+0x4d/0x80
  do_syscall_64+0x45/0xf0
  entry_SYSCALL_64_after_hwframe+0x6e/0x76

When the first RNIC is set down, the lgr->lnk[0] will be cleared and an
asymmetric link will be allocated in lgr->link[SMC_LINKS_PER_LGR_MAX - 1]
by smc_llc_alloc_alt_link(). Then when we try to dump SMC-R connections
in __smc_diag_dump(), the invalid lgr->lnk[0] will be accessed, resulting
in this issue. So fix it by accessing the right link.

Fixes: f16a7dd ("smc: netlink interface for SMC sockets")
Reported-by: henaumars <henaumars@sina.com>
Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=7616
Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
Reviewed-by: Tony Lu <tonylu@linux.alibaba.com>
Link: https://lore.kernel.org/r/1703662835-53416-1-git-send-email-guwen@linux.alibaba.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
anthraxx pushed a commit that referenced this pull request Jan 10, 2024
[ Upstream commit 9dbe086 ]

A crash was found when dumping SMC-R connections. It can be reproduced
by following steps:

- environment: two RNICs on both sides.
- run SMC-R between two sides, now a SMC_LGR_SYMMETRIC type link group
  will be created.
- set the first RNIC down on either side and link group will turn to
  SMC_LGR_ASYMMETRIC_LOCAL then.
- run 'smcss -R' and the crash will be triggered.

 BUG: kernel NULL pointer dereference, address: 0000000000000010
 #PF: supervisor read access in kernel mode
 #PF: error_code(0x0000) - not-present page
 PGD 8000000101fdd067 P4D 8000000101fdd067 PUD 10ce46067 PMD 0
 Oops: 0000 [#1] PREEMPT SMP PTI
 CPU: 3 PID: 1810 Comm: smcss Kdump: loaded Tainted: G W   E      6.7.0-rc6+ #51
 RIP: 0010:__smc_diag_dump.constprop.0+0x36e/0x620 [smc_diag]
 Call Trace:
  <TASK>
  ? __die+0x24/0x70
  ? page_fault_oops+0x66/0x150
  ? exc_page_fault+0x69/0x140
  ? asm_exc_page_fault+0x26/0x30
  ? __smc_diag_dump.constprop.0+0x36e/0x620 [smc_diag]
  smc_diag_dump_proto+0xd0/0xf0 [smc_diag]
  smc_diag_dump+0x26/0x60 [smc_diag]
  netlink_dump+0x19f/0x320
  __netlink_dump_start+0x1dc/0x300
  smc_diag_handler_dump+0x6a/0x80 [smc_diag]
  ? __pfx_smc_diag_dump+0x10/0x10 [smc_diag]
  sock_diag_rcv_msg+0x121/0x140
  ? __pfx_sock_diag_rcv_msg+0x10/0x10
  netlink_rcv_skb+0x5a/0x110
  sock_diag_rcv+0x28/0x40
  netlink_unicast+0x22a/0x330
  netlink_sendmsg+0x240/0x4a0
  __sock_sendmsg+0xb0/0xc0
  ____sys_sendmsg+0x24e/0x300
  ? copy_msghdr_from_user+0x62/0x80
  ___sys_sendmsg+0x7c/0xd0
  ? __do_fault+0x34/0x1a0
  ? do_read_fault+0x5f/0x100
  ? do_fault+0xb0/0x110
  __sys_sendmsg+0x4d/0x80
  do_syscall_64+0x45/0xf0
  entry_SYSCALL_64_after_hwframe+0x6e/0x76

When the first RNIC is set down, the lgr->lnk[0] will be cleared and an
asymmetric link will be allocated in lgr->link[SMC_LINKS_PER_LGR_MAX - 1]
by smc_llc_alloc_alt_link(). Then when we try to dump SMC-R connections
in __smc_diag_dump(), the invalid lgr->lnk[0] will be accessed, resulting
in this issue. So fix it by accessing the right link.

Fixes: f16a7dd ("smc: netlink interface for SMC sockets")
Reported-by: henaumars <henaumars@sina.com>
Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=7616
Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
Reviewed-by: Tony Lu <tonylu@linux.alibaba.com>
Link: https://lore.kernel.org/r/1703662835-53416-1-git-send-email-guwen@linux.alibaba.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
anthraxx pushed a commit that referenced this pull request Jan 27, 2024
A crash was found when dumping SMC-R connections. It can be reproduced
by following steps:

- environment: two RNICs on both sides.
- run SMC-R between two sides, now a SMC_LGR_SYMMETRIC type link group
  will be created.
- set the first RNIC down on either side and link group will turn to
  SMC_LGR_ASYMMETRIC_LOCAL then.
- run 'smcss -R' and the crash will be triggered.

 BUG: kernel NULL pointer dereference, address: 0000000000000010
 #PF: supervisor read access in kernel mode
 #PF: error_code(0x0000) - not-present page
 PGD 8000000101fdd067 P4D 8000000101fdd067 PUD 10ce46067 PMD 0
 Oops: 0000 [#1] PREEMPT SMP PTI
 CPU: 3 PID: 1810 Comm: smcss Kdump: loaded Tainted: G W   E      6.7.0-rc6+ #51
 RIP: 0010:__smc_diag_dump.constprop.0+0x36e/0x620 [smc_diag]
 Call Trace:
  <TASK>
  ? __die+0x24/0x70
  ? page_fault_oops+0x66/0x150
  ? exc_page_fault+0x69/0x140
  ? asm_exc_page_fault+0x26/0x30
  ? __smc_diag_dump.constprop.0+0x36e/0x620 [smc_diag]
  smc_diag_dump_proto+0xd0/0xf0 [smc_diag]
  smc_diag_dump+0x26/0x60 [smc_diag]
  netlink_dump+0x19f/0x320
  __netlink_dump_start+0x1dc/0x300
  smc_diag_handler_dump+0x6a/0x80 [smc_diag]
  ? __pfx_smc_diag_dump+0x10/0x10 [smc_diag]
  sock_diag_rcv_msg+0x121/0x140
  ? __pfx_sock_diag_rcv_msg+0x10/0x10
  netlink_rcv_skb+0x5a/0x110
  sock_diag_rcv+0x28/0x40
  netlink_unicast+0x22a/0x330
  netlink_sendmsg+0x240/0x4a0
  __sock_sendmsg+0xb0/0xc0
  ____sys_sendmsg+0x24e/0x300
  ? copy_msghdr_from_user+0x62/0x80
  ___sys_sendmsg+0x7c/0xd0
  ? __do_fault+0x34/0x1a0
  ? do_read_fault+0x5f/0x100
  ? do_fault+0xb0/0x110
  __sys_sendmsg+0x4d/0x80
  do_syscall_64+0x45/0xf0
  entry_SYSCALL_64_after_hwframe+0x6e/0x76

When the first RNIC is set down, the lgr->lnk[0] will be cleared and an
asymmetric link will be allocated in lgr->link[SMC_LINKS_PER_LGR_MAX - 1]
by smc_llc_alloc_alt_link(). Then when we try to dump SMC-R connections
in __smc_diag_dump(), the invalid lgr->lnk[0] will be accessed, resulting
in this issue. So fix it by accessing the right link.

Fixes: f16a7dd ("smc: netlink interface for SMC sockets")
Reported-by: henaumars <henaumars@sina.com>
Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=7616
Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
Reviewed-by: Tony Lu <tonylu@linux.alibaba.com>
Link: https://lore.kernel.org/r/1703662835-53416-1-git-send-email-guwen@linux.alibaba.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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