Longterm releases? #48

nullchinchilla · 2017-07-17T15:04:02Z

I feel like a hardened version of longterm kernel releases would be very useful, as it then allows easy usage on systems such as Debian and Ubuntu LTS with conservative update schedules. Hardened kernels would be very useful on public servers, which tend to run conservative distros. Besides, longterm releases like 4.9.x and 4.4.x change slowly and publicly available grsec patches, so it'll probably be easier to port various features compared to doing the same thing on the quickly moving target that is the stable version.

thestinger · 2017-07-18T00:06:23Z

It's not within the current scope and there's no way it would happen with kernel branches older than the project. It started with 4.11. If and when there's a substantial amount of development happening here, splitting up resources across multiple branches can be considered. It's currently not very active.

[ Upstream commit 36b6f9f ] Lockdep warns about a potential deadlock: [ 66.782842] ====================================================== [ 66.782888] WARNING: possible circular locking dependency detected [ 66.782937] 4.14.0-rc2-test-test+ #48 Not tainted [ 66.782983] ------------------------------------------------------ [ 66.783052] umount/336 is trying to acquire lock: [ 66.783117] (cpu_hotplug_lock.rw_sem){++++}, at: [<ffffffff81032395>] rdt_kill_sb+0x215/0x390 [ 66.783193] but task is already holding lock: [ 66.783244] (rdtgroup_mutex){+.+.}, at: [<ffffffff810321b6>] rdt_kill_sb+0x36/0x390 [ 66.783305] which lock already depends on the new lock. [ 66.783364] the existing dependency chain (in reverse order) is: [ 66.783419] -> #3 (rdtgroup_mutex){+.+.}: [ 66.783467] __lock_acquire+0x1293/0x13f0 [ 66.783509] lock_acquire+0xaf/0x220 [ 66.783543] __mutex_lock+0x71/0x9b0 [ 66.783575] mutex_lock_nested+0x1b/0x20 [ 66.783610] intel_rdt_online_cpu+0x3b/0x430 [ 66.783649] cpuhp_invoke_callback+0xab/0x8e0 [ 66.783687] cpuhp_thread_fun+0x7a/0x150 [ 66.783722] smpboot_thread_fn+0x1cc/0x270 [ 66.783764] kthread+0x16e/0x190 [ 66.783794] ret_from_fork+0x27/0x40 [ 66.783825] -> #2 (cpuhp_state){+.+.}: [ 66.783870] __lock_acquire+0x1293/0x13f0 [ 66.783906] lock_acquire+0xaf/0x220 [ 66.783938] cpuhp_issue_call+0x102/0x170 [ 66.783974] __cpuhp_setup_state_cpuslocked+0x154/0x2a0 [ 66.784023] __cpuhp_setup_state+0xc7/0x170 [ 66.784061] page_writeback_init+0x43/0x67 [ 66.784097] pagecache_init+0x43/0x4a [ 66.784131] start_kernel+0x3ad/0x3f7 [ 66.784165] x86_64_start_reservations+0x2a/0x2c [ 66.784204] x86_64_start_kernel+0x72/0x75 [ 66.784241] verify_cpu+0x0/0xfb [ 66.784270] -> #1 (cpuhp_state_mutex){+.+.}: [ 66.784319] __lock_acquire+0x1293/0x13f0 [ 66.784355] lock_acquire+0xaf/0x220 [ 66.784387] __mutex_lock+0x71/0x9b0 [ 66.784419] mutex_lock_nested+0x1b/0x20 [ 66.784454] __cpuhp_setup_state_cpuslocked+0x52/0x2a0 [ 66.784497] __cpuhp_setup_state+0xc7/0x170 [ 66.784535] page_alloc_init+0x28/0x30 [ 66.784569] start_kernel+0x148/0x3f7 [ 66.784602] x86_64_start_reservations+0x2a/0x2c [ 66.784642] x86_64_start_kernel+0x72/0x75 [ 66.784678] verify_cpu+0x0/0xfb [ 66.784707] -> #0 (cpu_hotplug_lock.rw_sem){++++}: [ 66.784759] check_prev_add+0x32f/0x6e0 [ 66.784794] __lock_acquire+0x1293/0x13f0 [ 66.784830] lock_acquire+0xaf/0x220 [ 66.784863] cpus_read_lock+0x3d/0xb0 [ 66.784896] rdt_kill_sb+0x215/0x390 [ 66.784930] deactivate_locked_super+0x3e/0x70 [ 66.784968] deactivate_super+0x40/0x60 [ 66.785003] cleanup_mnt+0x3f/0x80 [ 66.785034] __cleanup_mnt+0x12/0x20 [ 66.785070] task_work_run+0x8b/0xc0 [ 66.785103] exit_to_usermode_loop+0x94/0xa0 [ 66.786804] syscall_return_slowpath+0xe8/0x150 [ 66.788502] entry_SYSCALL_64_fastpath+0xab/0xad [ 66.790194] other info that might help us debug this: [ 66.795139] Chain exists of: cpu_hotplug_lock.rw_sem --> cpuhp_state --> rdtgroup_mutex [ 66.800035] Possible unsafe locking scenario: [ 66.803267] CPU0 CPU1 [ 66.804867] ---- ---- [ 66.806443] lock(rdtgroup_mutex); [ 66.808002] lock(cpuhp_state); [ 66.809565] lock(rdtgroup_mutex); [ 66.811110] lock(cpu_hotplug_lock.rw_sem); [ 66.812608] *** DEADLOCK *** [ 66.816983] 2 locks held by umount/336: [ 66.818418] #0: (&type->s_umount_key#35){+.+.}, at: [<ffffffff81229738>] deactivate_super+0x38/0x60 [ 66.819922] #1: (rdtgroup_mutex){+.+.}, at: [<ffffffff810321b6>] rdt_kill_sb+0x36/0x390 When the resctrl filesystem is unmounted the locks should be obtain in the locks in the same order as was done when the cpus came online: cpu_hotplug_lock before rdtgroup_mutex. This also requires to switch the static_branch_disable() calls to the _cpulocked variant because now cpu hotplug lock is held already. [ tglx: Switched to cpus_read_[un]lock ] Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com> Acked-by: Vikas Shivappa <vikas.shivappa@linux.intel.com> Acked-by: Fenghua Yu <fenghua.yu@intel.com> Acked-by: Tony Luck <tony.luck@intel.com> Link: https://lkml.kernel.org/r/cc292e76be073f7260604651711c47b09fd0dc81.1508490116.git.reinette.chatre@intel.com Signed-off-by: Sasha Levin <alexander.levin@verizon.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

[ Upstream commit 92a4728 ] Dirk Gouders reported that two consecutive "make" invocations on an already compiled tree will show alternating behaviors: $ make CALL scripts/checksyscalls.sh DESCEND objtool CHK include/generated/compile.h DATAREL arch/x86/boot/compressed/vmlinux Kernel: arch/x86/boot/bzImage is ready (#48) Building modules, stage 2. MODPOST 165 modules $ make CALL scripts/checksyscalls.sh DESCEND objtool CHK include/generated/compile.h LD arch/x86/boot/compressed/vmlinux ZOFFSET arch/x86/boot/zoffset.h AS arch/x86/boot/header.o LD arch/x86/boot/setup.elf OBJCOPY arch/x86/boot/setup.bin OBJCOPY arch/x86/boot/vmlinux.bin BUILD arch/x86/boot/bzImage Setup is 15644 bytes (padded to 15872 bytes). System is 6663 kB CRC 3eb90f40 Kernel: arch/x86/boot/bzImage is ready (#48) Building modules, stage 2. MODPOST 165 modules He bisected it back to: commit 98f7852 ("x86/boot: Refuse to build with data relocations") The root cause was the use of the "if_changed" kbuild function multiple times for the same target. It was designed to only be used once per target, otherwise it will effectively always trigger, flipping back and forth between the two commands getting recorded by "if_changed". Instead, this patch merges the two commands into a single function to get stable build artifacts (i.e. .vmlinux.cmd), and a single build behavior. Bisected-and-Reported-by: Dirk Gouders <dirk@gouders.net> Fix-Suggested-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20180724230827.GA37823@beast Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Increase kasan instrumented kernel stack size from 32k to 64k. Other architectures seems to get away with just doubling kernel stack size under kasan, but on s390 this appears to be not enough due to bigger frame size. The particular pain point is kasan inlined checks (CONFIG_KASAN_INLINE vs CONFIG_KASAN_OUTLINE). With inlined checks one particular case hitting stack overflow is fs sync on xfs filesystem: #0 [9a0681e8] 704 bytes check_usage at 34b1fc GrapheneOS#1 [9a0684a8] 432 bytes check_usage at 34c710 GrapheneOS#2 [9a068658] 1048 bytes validate_chain at 35044a GrapheneOS#3 [9a068a70] 312 bytes __lock_acquire at 3559fe GrapheneOS#4 [9a068ba8] 440 bytes lock_acquire at 3576ee GrapheneOS#5 [9a068d60] 104 bytes _raw_spin_lock at 21b44e0 GrapheneOS#6 [9a068dc8] 1992 bytes enqueue_entity at 2dbf72 GrapheneOS#7 [9a069590] 1496 bytes enqueue_task_fair at 2df5f0 GrapheneOS#8 [9a069b68] 64 bytes ttwu_do_activate at 28f438 GrapheneOS#9 [9a069ba8] 552 bytes try_to_wake_up at 298c4c GrapheneOS#10 [9a069dd0] 168 bytes wake_up_worker at 23f97c GrapheneOS#11 [9a069e78] 200 bytes insert_work at 23fc2e GrapheneOS#12 [9a069f40] 648 bytes __queue_work at 2487c0 GrapheneOS#13 [9a06a1c8] 200 bytes __queue_delayed_work at 24db28 GrapheneOS#14 [9a06a290] 248 bytes mod_delayed_work_on at 24de84 GrapheneOS#15 [9a06a388] 24 bytes kblockd_mod_delayed_work_on at 153e2a0 GrapheneOS#16 [9a06a3a0] 288 bytes __blk_mq_delay_run_hw_queue at 158168c GrapheneOS#17 [9a06a4c0] 192 bytes blk_mq_run_hw_queue at 1581a3c GrapheneOS#18 [9a06a580] 184 bytes blk_mq_sched_insert_requests at 15a2192 GrapheneOS#19 [9a06a638] 1024 bytes blk_mq_flush_plug_list at 1590f3a GrapheneOS#20 [9a06aa38] 704 bytes blk_flush_plug_list at 1555028 GrapheneOS#21 [9a06acf8] 320 bytes schedule at 219e476 GrapheneOS#22 [9a06ae38] 760 bytes schedule_timeout at 21b0aac GrapheneOS#23 [9a06b130] 408 bytes wait_for_common at 21a1706 GrapheneOS#24 [9a06b2c8] 360 bytes xfs_buf_iowait at fa1540 GrapheneOS#25 [9a06b430] 256 bytes __xfs_buf_submit at fadae6 GrapheneOS#26 [9a06b530] 264 bytes xfs_buf_read_map at fae3f6 GrapheneOS#27 [9a06b638] 656 bytes xfs_trans_read_buf_map at 10ac9a8 GrapheneOS#28 [9a06b8c8] 304 bytes xfs_btree_kill_root at e72426 GrapheneOS#29 [9a06b9f8] 288 bytes xfs_btree_lookup_get_block at e7bc5e GrapheneOS#30 [9a06bb18] 624 bytes xfs_btree_lookup at e7e1a6 GrapheneOS#31 [9a06bd88] 2664 bytes xfs_alloc_ag_vextent_near at dfa070 GrapheneOS#32 [9a06c7f0] 144 bytes xfs_alloc_ag_vextent at dff3ca GrapheneOS#33 [9a06c880] 1128 bytes xfs_alloc_vextent at e05fce GrapheneOS#34 [9a06cce8] 584 bytes xfs_bmap_btalloc at e58342 GrapheneOS#35 [9a06cf30] 1336 bytes xfs_bmapi_write at e618de GrapheneOS#36 [9a06d468] 776 bytes xfs_iomap_write_allocate at ff678e GrapheneOS#37 [9a06d770] 720 bytes xfs_map_blocks at f82af8 GrapheneOS#38 [9a06da40] 928 bytes xfs_writepage_map at f83cd6 GrapheneOS#39 [9a06dde0] 320 bytes xfs_do_writepage at f85872 GrapheneOS#40 [9a06df20] 1320 bytes write_cache_pages at 73dfe8 GrapheneOS#41 [9a06e448] 208 bytes xfs_vm_writepages at f7f892 GrapheneOS#42 [9a06e518] 88 bytes do_writepages at 73fe6a GrapheneOS#43 [9a06e570] 872 bytes __writeback_single_inode at a20cb6 GrapheneOS#44 [9a06e8d8] 664 bytes writeback_sb_inodes at a23be2 GrapheneOS#45 [9a06eb70] 296 bytes __writeback_inodes_wb at a242e0 GrapheneOS#46 [9a06ec98] 928 bytes wb_writeback at a2500e GrapheneOS#47 [9a06f038] 848 bytes wb_do_writeback at a260ae GrapheneOS#48 [9a06f388] 536 bytes wb_workfn at a28228 GrapheneOS#49 [9a06f5a0] 1088 bytes process_one_work at 24a234 GrapheneOS#50 [9a06f9e0] 1120 bytes worker_thread at 24ba26 GrapheneOS#51 [9a06fe40] 104 bytes kthread at 26545a GrapheneOS#52 [9a06fea8] kernel_thread_starter at 21b6b62 To be able to increase the stack size to 64k reuse LLILL instruction in __switch_to function to load 64k - STACK_FRAME_OVERHEAD - __PT_SIZE (65192) value as unsigned. Reported-by: Benjamin Block <bblock@linux.ibm.com> Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

After commit 3c83dd5 ("wlcore: Add support for optional wakeirq") landed upstream, I started seeing the following oops on my HiKey board: [ 1.870279] Unable to handle kernel read from unreadable memory at virtual address 0000000000000010 [ 1.870283] Mem abort info: [ 1.870287] ESR = 0x96000005 [ 1.870292] Exception class = DABT (current EL), IL = 32 bits [ 1.870296] SET = 0, FnV = 0 [ 1.870299] EA = 0, S1PTW = 0 [ 1.870302] Data abort info: [ 1.870306] ISV = 0, ISS = 0x00000005 [ 1.870309] CM = 0, WnR = 0 [ 1.870312] [0000000000000010] user address but active_mm is swapper [ 1.870318] Internal error: Oops: 96000005 [GrapheneOS#1] PREEMPT SMP [ 1.870327] CPU: 0 PID: 5 Comm: kworker/0:0 Not tainted 4.19.0-05129-gb3d1e8e GrapheneOS#48 [ 1.870331] Hardware name: HiKey Development Board (DT) [ 1.870350] Workqueue: events_freezable mmc_rescan [ 1.870358] pstate: 60400005 (nZCv daif +PAN -UAO) [ 1.870366] pc : wl1271_probe+0x210/0x350 [ 1.870371] lr : wl1271_probe+0x210/0x350 [ 1.870374] sp : ffffff80080739b0 [ 1.870377] x29: ffffff80080739b0 x28: 0000000000000000 [ 1.870384] x27: 0000000000000000 x26: 0000000000000000 [ 1.870391] x25: 0000000000000036 x24: ffffffc074ecb598 [ 1.870398] x23: ffffffc07ffdce78 x22: ffffffc0744ed808 [ 1.870404] x21: ffffffc074ecbb98 x20: ffffff8008ff9000 [ 1.870411] x19: ffffffc0744ed800 x18: ffffff8008ff9a48 [ 1.870418] x17: 0000000000000000 x16: 0000000000000000 [ 1.870425] x15: ffffffc074ecb503 x14: ffffffffffffffff [ 1.870431] x13: ffffffc074ecb502 x12: 0000000000000030 [ 1.870438] x11: 0101010101010101 x10: 0000000000000040 [ 1.870444] x9 : ffffffc075400248 x8 : ffffffc075400270 [ 1.870451] x7 : 0000000000000000 x6 : 0000000000000000 [ 1.870457] x5 : 0000000000000000 x4 : 0000000000000000 [ 1.870463] x3 : 0000000000000000 x2 : 0000000000000000 [ 1.870469] x1 : 0000000000000028 x0 : 0000000000000000 [ 1.870477] Process kworker/0:0 (pid: 5, stack limit = 0x(____ptrval____)) [ 1.870480] Call trace: [ 1.870485] wl1271_probe+0x210/0x350 [ 1.870491] sdio_bus_probe+0x100/0x128 [ 1.870500] really_probe+0x1a8/0x2b8 [ 1.870506] driver_probe_device+0x58/0x100 [ 1.870511] __device_attach_driver+0x94/0xd8 [ 1.870517] bus_for_each_drv+0x70/0xc8 [ 1.870522] __device_attach+0xe0/0x140 [ 1.870527] device_initial_probe+0x10/0x18 [ 1.870532] bus_probe_device+0x94/0xa0 [ 1.870537] device_add+0x374/0x5b8 [ 1.870542] sdio_add_func+0x60/0x88 [ 1.870546] mmc_attach_sdio+0x1b0/0x358 [ 1.870551] mmc_rescan+0x2cc/0x390 [ 1.870558] process_one_work+0x12c/0x320 [ 1.870563] worker_thread+0x48/0x458 [ 1.870569] kthread+0xf8/0x128 [ 1.870575] ret_from_fork+0x10/0x18 [ 1.870583] Code: 92400c21 b2760021 a90687a2 97e95bf9 (f9400803) [ 1.870587] ---[ end trace 1e15f81d3c139ca9 ]--- It seems since we don't have a wakeirq value in the dts, the wakeirq value in wl1271_probe() is zero, which then causes trouble in irqd_get_trigger_type(irq_get_irq_data(wakeirq)). This patch tries to address this by checking if wakeirq is zero, and not trying to add it to the resources if that is the case. Fixes: 3c83dd5 ("wlcore: Add support for optional wakeirq") Cc: Tony Lindgren <tony@atomide.com> Cc: Kalle Valo <kvalo@codeaurora.org> Cc: Eyal Reizer <eyalr@ti.com> Cc: Anders Roxell <anders.roxell@linaro.org> Cc: linux-wireless@vger.kernel.org Acked-by: Tony Lindgren <tony@atomide.com> Signed-off-by: John Stultz <john.stultz@linaro.org> Tested-by: Anders Roxell <anders.roxell@linaro.org> Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

[ Upstream commit dd09fad ] Commit: 3a6b6c6 ("efi: Make EFI_MEMORY_ATTRIBUTES_TABLE initialization common across all architectures") moved the call to efi_memattr_init() from ARM specific to the generic EFI init code, in order to be able to apply the restricted permissions described in that table on x86 as well. We never enabled this feature fully on i386, and so mapping and reserving this table is pointless. However, due to the early call to memblock_reserve(), the memory bookkeeping gets confused to the point where it produces the splat below when we try to map the memory later on: ------------[ cut here ]------------ ioremap on RAM at 0x3f251000 - 0x3fa1afff WARNING: CPU: 0 PID: 0 at arch/x86/mm/ioremap.c:166 __ioremap_caller ... Modules linked in: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.20.0 #48 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015 EIP: __ioremap_caller.constprop.0+0x249/0x260 Code: 90 0f b7 05 4e 38 40 de 09 45 e0 e9 09 ff ff ff 90 8d 45 ec c6 05 ... EAX: 00000029 EBX: 00000000 ECX: de59c228 EDX: 00000001 ESI: 3f250fff EDI: 00000000 EBP: de3edf20 ESP: de3edee0 DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00200296 CR0: 80050033 CR2: ffd17000 CR3: 1e58c000 CR4: 00040690 Call Trace: ioremap_cache+0xd/0x10 ? old_map_region+0x72/0x9d old_map_region+0x72/0x9d efi_map_region+0x8/0xa efi_enter_virtual_mode+0x260/0x43b start_kernel+0x329/0x3aa i386_start_kernel+0xa7/0xab startup_32_smp+0x164/0x168 ---[ end trace e15ccf6b9f356833 ]--- Let's work around this by disregarding the memory attributes table altogether on i386, which does not result in a loss of functionality or protection, given that we never consumed the contents. Fixes: 3a6b6c6 ("efi: Make EFI_MEMORY_ATTRIBUTES_TABLE ... ") Tested-by: Arvind Sankar <nivedita@alum.mit.edu> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20200304165917.5893-1-ardb@kernel.org Link: https://lore.kernel.org/r/20200308080859.21568-21-ardb@kernel.org Signed-off-by: Sasha Levin <sashal@kernel.org>

…f fs_info::journal_info commit fcc9973 upstream. [BUG] One run of btrfs/063 triggered the following lockdep warning: ============================================ WARNING: possible recursive locking detected 5.6.0-rc7-custom+ #48 Not tainted -------------------------------------------- kworker/u24:0/7 is trying to acquire lock: ffff88817d3a46e0 (sb_internal#2){.+.+}, at: start_transaction+0x66c/0x890 [btrfs] but task is already holding lock: ffff88817d3a46e0 (sb_internal#2){.+.+}, at: start_transaction+0x66c/0x890 [btrfs] other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(sb_internal#2); lock(sb_internal#2); *** DEADLOCK *** May be due to missing lock nesting notation 4 locks held by kworker/u24:0/7: #0: ffff88817b495948 ((wq_completion)btrfs-endio-write){+.+.}, at: process_one_work+0x557/0xb80 #1: ffff888189ea7db8 ((work_completion)(&work->normal_work)){+.+.}, at: process_one_work+0x557/0xb80 #2: ffff88817d3a46e0 (sb_internal#2){.+.+}, at: start_transaction+0x66c/0x890 [btrfs] #3: ffff888174ca4da8 (&fs_info->reloc_mutex){+.+.}, at: btrfs_record_root_in_trans+0x83/0xd0 [btrfs] stack backtrace: CPU: 0 PID: 7 Comm: kworker/u24:0 Not tainted 5.6.0-rc7-custom+ #48 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 Workqueue: btrfs-endio-write btrfs_work_helper [btrfs] Call Trace: dump_stack+0xc2/0x11a __lock_acquire.cold+0xce/0x214 lock_acquire+0xe6/0x210 __sb_start_write+0x14e/0x290 start_transaction+0x66c/0x890 [btrfs] btrfs_join_transaction+0x1d/0x20 [btrfs] find_free_extent+0x1504/0x1a50 [btrfs] btrfs_reserve_extent+0xd5/0x1f0 [btrfs] btrfs_alloc_tree_block+0x1ac/0x570 [btrfs] btrfs_copy_root+0x213/0x580 [btrfs] create_reloc_root+0x3bd/0x470 [btrfs] btrfs_init_reloc_root+0x2d2/0x310 [btrfs] record_root_in_trans+0x191/0x1d0 [btrfs] btrfs_record_root_in_trans+0x90/0xd0 [btrfs] start_transaction+0x16e/0x890 [btrfs] btrfs_join_transaction+0x1d/0x20 [btrfs] btrfs_finish_ordered_io+0x55d/0xcd0 [btrfs] finish_ordered_fn+0x15/0x20 [btrfs] btrfs_work_helper+0x116/0x9a0 [btrfs] process_one_work+0x632/0xb80 worker_thread+0x80/0x690 kthread+0x1a3/0x1f0 ret_from_fork+0x27/0x50 It's pretty hard to reproduce, only one hit so far. [CAUSE] This is because we're calling btrfs_join_transaction() without re-using the current running one: btrfs_finish_ordered_io() |- btrfs_join_transaction() <<< Call #1 |- btrfs_record_root_in_trans() |- btrfs_reserve_extent() |- btrfs_join_transaction() <<< Call #2 Normally such btrfs_join_transaction() call should re-use the existing one, without trying to re-start a transaction. But the problem is, in btrfs_join_transaction() call #1, we call btrfs_record_root_in_trans() before initializing current::journal_info. And in btrfs_join_transaction() call #2, we're relying on current::journal_info to avoid such deadlock. [FIX] Call btrfs_record_root_in_trans() after we have initialized current::journal_info. CC: stable@vger.kernel.org # 4.4+ Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

…f fs_info::journal_info [BUG] One run of btrfs/063 triggered the following lockdep warning: ============================================ WARNING: possible recursive locking detected 5.6.0-rc7-custom+ #48 Not tainted -------------------------------------------- kworker/u24:0/7 is trying to acquire lock: ffff88817d3a46e0 (sb_internal#2){.+.+}, at: start_transaction+0x66c/0x890 [btrfs] but task is already holding lock: ffff88817d3a46e0 (sb_internal#2){.+.+}, at: start_transaction+0x66c/0x890 [btrfs] other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(sb_internal#2); lock(sb_internal#2); *** DEADLOCK *** May be due to missing lock nesting notation 4 locks held by kworker/u24:0/7: #0: ffff88817b495948 ((wq_completion)btrfs-endio-write){+.+.}, at: process_one_work+0x557/0xb80 #1: ffff888189ea7db8 ((work_completion)(&work->normal_work)){+.+.}, at: process_one_work+0x557/0xb80 #2: ffff88817d3a46e0 (sb_internal#2){.+.+}, at: start_transaction+0x66c/0x890 [btrfs] #3: ffff888174ca4da8 (&fs_info->reloc_mutex){+.+.}, at: btrfs_record_root_in_trans+0x83/0xd0 [btrfs] stack backtrace: CPU: 0 PID: 7 Comm: kworker/u24:0 Not tainted 5.6.0-rc7-custom+ #48 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 Workqueue: btrfs-endio-write btrfs_work_helper [btrfs] Call Trace: dump_stack+0xc2/0x11a __lock_acquire.cold+0xce/0x214 lock_acquire+0xe6/0x210 __sb_start_write+0x14e/0x290 start_transaction+0x66c/0x890 [btrfs] btrfs_join_transaction+0x1d/0x20 [btrfs] find_free_extent+0x1504/0x1a50 [btrfs] btrfs_reserve_extent+0xd5/0x1f0 [btrfs] btrfs_alloc_tree_block+0x1ac/0x570 [btrfs] btrfs_copy_root+0x213/0x580 [btrfs] create_reloc_root+0x3bd/0x470 [btrfs] btrfs_init_reloc_root+0x2d2/0x310 [btrfs] record_root_in_trans+0x191/0x1d0 [btrfs] btrfs_record_root_in_trans+0x90/0xd0 [btrfs] start_transaction+0x16e/0x890 [btrfs] btrfs_join_transaction+0x1d/0x20 [btrfs] btrfs_finish_ordered_io+0x55d/0xcd0 [btrfs] finish_ordered_fn+0x15/0x20 [btrfs] btrfs_work_helper+0x116/0x9a0 [btrfs] process_one_work+0x632/0xb80 worker_thread+0x80/0x690 kthread+0x1a3/0x1f0 ret_from_fork+0x27/0x50 It's pretty hard to reproduce, only one hit so far. [CAUSE] This is because we're calling btrfs_join_transaction() without re-using the current running one: btrfs_finish_ordered_io() |- btrfs_join_transaction() <<< Call #1 |- btrfs_record_root_in_trans() |- btrfs_reserve_extent() |- btrfs_join_transaction() <<< Call #2 Normally such btrfs_join_transaction() call should re-use the existing one, without trying to re-start a transaction. But the problem is, in btrfs_join_transaction() call #1, we call btrfs_record_root_in_trans() before initializing current::journal_info. And in btrfs_join_transaction() call #2, we're relying on current::journal_info to avoid such deadlock. [FIX] Call btrfs_record_root_in_trans() after we have initialized current::journal_info. CC: stable@vger.kernel.org # 4.4+ Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>

commit f4c23a1 upstream. I got null-ptr-deref in serial8250_start_tx(): [ 78.114630] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 [ 78.123778] Mem abort info: [ 78.126560] ESR = 0x86000007 [ 78.129603] EC = 0x21: IABT (current EL), IL = 32 bits [ 78.134891] SET = 0, FnV = 0 [ 78.137933] EA = 0, S1PTW = 0 [ 78.141064] user pgtable: 64k pages, 48-bit VAs, pgdp=00000027d41a8600 [ 78.147562] [0000000000000000] pgd=00000027893f0003, p4d=00000027893f0003, pud=00000027893f0003, pmd=00000027c9a20003, pte=0000000000000000 [ 78.160029] Internal error: Oops: 86000007 [#1] SMP [ 78.164886] Modules linked in: sunrpc vfat fat aes_ce_blk crypto_simd cryptd aes_ce_cipher crct10dif_ce ghash_ce sha2_ce sha256_arm64 sha1_ce ses enclosure sg sbsa_gwdt ipmi_ssif spi_dw_mmio sch_fq_codel vhost_net tun vhost vhost_iotlb tap ip_tables ext4 mbcache jbd2 ahci hisi_sas_v3_hw libahci hisi_sas_main libsas hns3 scsi_transport_sas hclge libata megaraid_sas ipmi_si hnae3 ipmi_devintf ipmi_msghandler br_netfilter bridge stp llc nvme nvme_core xt_sctp sctp libcrc32c dm_mod nbd [ 78.207383] CPU: 11 PID: 23258 Comm: null-ptr Not tainted 5.8.0-rc6+ #48 [ 78.214056] Hardware name: Huawei TaiShan 2280 V2/BC82AMDC, BIOS 2280-V2 CS V3.B210.01 03/12/2020 [ 78.222888] pstate: 80400089 (Nzcv daIf +PAN -UAO BTYPE=--) [ 78.228435] pc : 0x0 [ 78.230618] lr : serial8250_start_tx+0x160/0x260 [ 78.235215] sp : ffff800062eefb80 [ 78.238517] x29: ffff800062eefb80 x28: 0000000000000fff [ 78.243807] x27: ffff800062eefd80 x26: ffff202fd83b3000 [ 78.249098] x25: ffff800062eefd80 x24: ffff202fd83b3000 [ 78.254388] x23: ffff002fc5e50be8 x22: 0000000000000002 [ 78.259679] x21: 0000000000000001 x20: 0000000000000000 [ 78.264969] x19: ffffa688827eecc8 x18: 0000000000000000 [ 78.270259] x17: 0000000000000000 x16: 0000000000000000 [ 78.275550] x15: ffffa68881bc67a8 x14: 00000000000002e6 [ 78.280841] x13: ffffa68881bc67a8 x12: 000000000000c539 [ 78.286131] x11: d37a6f4de9bd37a7 x10: ffffa68881cccff0 [ 78.291421] x9 : ffffa68881bc6000 x8 : ffffa688819daa88 [ 78.296711] x7 : ffffa688822a0f20 x6 : ffffa688819e0000 [ 78.302002] x5 : ffff800062eef9d0 x4 : ffffa68881e707a8 [ 78.307292] x3 : 0000000000000000 x2 : 0000000000000002 [ 78.312582] x1 : 0000000000000001 x0 : ffffa688827eecc8 [ 78.317873] Call trace: [ 78.320312] 0x0 [ 78.322147] __uart_start.isra.9+0x64/0x78 [ 78.326229] uart_start+0xb8/0x1c8 [ 78.329620] uart_flush_chars+0x24/0x30 [ 78.333442] n_tty_receive_buf_common+0x7b0/0xc30 [ 78.338128] n_tty_receive_buf+0x44/0x2c8 [ 78.342122] tty_ioctl+0x348/0x11f8 [ 78.345599] ksys_ioctl+0xd8/0xf8 [ 78.348903] __arm64_sys_ioctl+0x2c/0xc8 [ 78.352812] el0_svc_common.constprop.2+0x88/0x1b0 [ 78.357583] do_el0_svc+0x44/0xd0 [ 78.360887] el0_sync_handler+0x14c/0x1d0 [ 78.364880] el0_sync+0x140/0x180 [ 78.368185] Code: bad PC value SERIAL_PORT_DFNS is not defined on each arch, if it's not defined, serial8250_set_defaults() won't be called in serial8250_isa_init_ports(), so the p->serial_in pointer won't be initialized, and it leads a null-ptr-deref. Fix this problem by calling serial8250_set_defaults() after init uart port. Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> Cc: stable <stable@vger.kernel.org> Link: https://lore.kernel.org/r/20200721143852.4058352-1-yangyingliang@huawei.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

thestinger closed this as completed Jul 18, 2017

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Longterm releases? #48

Longterm releases? #48

nullchinchilla commented Jul 17, 2017

thestinger commented Jul 18, 2017

Longterm releases? #48

Longterm releases? #48

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nullchinchilla commented Jul 17, 2017

thestinger commented Jul 18, 2017