[syzbot] [ocfs2?] possible deadlock in ocfs2_finish_quota_recovery

[syzbot] [ocfs2?] possible deadlock in ocfs2_finish_quota_recovery

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    69b8923f5003 Merge tag 'for-linus-6.14-ofs4' of git://git...
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=100c4eb0580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=57ab43c279fa614d
dashboard link: https://syzkaller.appspot.com/bug?extid=f59a1ae7b7227c859b8f
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/ea84ac864e92/disk-69b8923f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6a465997b4e0/vmlinux-69b8923f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d72b67b2bd15/bzImage-69b8923f.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f59a1ae7b7227c859b8f@syzkaller.appspotmail.com

ocfs2: Finishing quota recovery on device (7,0) for slot 0
======================================================
WARNING: possible circular locking dependency detected
6.13.0-syzkaller-09793-g69b8923f5003 #0 Not tainted
------------------------------------------------------
kworker/u8:6/1142 is trying to acquire lock:
ffff888055ab40e0 (&type->s_umount_key#51){++++}-{4:4}, at: ocfs2_finish_quota_recovery+0x15c/0x22a0 fs/ocfs2/quota_local.c:603

but task is already holding lock:
ffffc90003c4fc60 ((work_completion)(&journal->j_recovery_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline]
ffffc90003c4fc60 ((work_completion)(&journal->j_recovery_work)){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1840 kernel/workqueue.c:3317

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 ((work_completion)(&journal->j_recovery_work)){+.+.}-{0:0}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
       process_one_work kernel/workqueue.c:3212 [inline]
       process_scheduled_works+0x994/0x1840 kernel/workqueue.c:3317
       worker_thread+0x870/0xd30 kernel/workqueue.c:3398
       kthread+0x7a9/0x920 kernel/kthread.c:464
       ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

-> #1 ((wq_completion)ocfs2_wq){+.+.}-{0:0}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
       touch_wq_lockdep_map+0xc7/0x170 kernel/workqueue.c:3905
       __flush_workqueue+0x14a/0x1280 kernel/workqueue.c:3947
       ocfs2_shutdown_local_alloc+0x109/0xa90 fs/ocfs2/localalloc.c:380
       ocfs2_dismount_volume+0x202/0x910 fs/ocfs2/super.c:1822
       generic_shutdown_super+0x139/0x2d0 fs/super.c:642
       kill_block_super+0x44/0x90 fs/super.c:1710
       deactivate_locked_super+0xc4/0x130 fs/super.c:473
       cleanup_mnt+0x41f/0x4b0 fs/namespace.c:1413
       task_work_run+0x24f/0x310 kernel/task_work.c:227
       resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
       exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
       exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
       __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
       syscall_exit_to_user_mode+0x13f/0x340 kernel/entry/common.c:218
       do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&type->s_umount_key#51){++++}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3163 [inline]
       check_prevs_add kernel/locking/lockdep.c:3282 [inline]
       validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3906
       __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5228
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
       down_read+0xb1/0xa40 kernel/locking/rwsem.c:1524
       ocfs2_finish_quota_recovery+0x15c/0x22a0 fs/ocfs2/quota_local.c:603
       ocfs2_complete_recovery+0x17c1/0x25c0 fs/ocfs2/journal.c:1357
       process_one_work kernel/workqueue.c:3236 [inline]
       process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3317
       worker_thread+0x870/0xd30 kernel/workqueue.c:3398
       kthread+0x7a9/0x920 kernel/kthread.c:464
       ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

other info that might help us debug this:

Chain exists of:
  &type->s_umount_key#51 --> (wq_completion)ocfs2_wq --> (work_completion)(&journal->j_recovery_work)

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock((work_completion)(&journal->j_recovery_work));
                               lock((wq_completion)ocfs2_wq);
                               lock((work_completion)(&journal->j_recovery_work));
  rlock(&type->s_umount_key#51);

 *** DEADLOCK ***

2 locks held by kworker/u8:6/1142:
 #0: ffff88802420b148 ((wq_completion)ocfs2_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline]
 #0: ffff88802420b148 ((wq_completion)ocfs2_wq){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1840 kernel/workqueue.c:3317
 #1: ffffc90003c4fc60 ((work_completion)(&journal->j_recovery_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline]
 #1: ffffc90003c4fc60 ((work_completion)(&journal->j_recovery_work)){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1840 kernel/workqueue.c:3317

stack backtrace:
CPU: 0 UID: 0 PID: 1142 Comm: kworker/u8:6 Not tainted 6.13.0-syzkaller-09793-g69b8923f5003 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Workqueue: ocfs2_wq ocfs2_complete_recovery
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2076
 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2208
 check_prev_add kernel/locking/lockdep.c:3163 [inline]
 check_prevs_add kernel/locking/lockdep.c:3282 [inline]
 validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3906
 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5228
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
 down_read+0xb1/0xa40 kernel/locking/rwsem.c:1524
 ocfs2_finish_quota_recovery+0x15c/0x22a0 fs/ocfs2/quota_local.c:603
 ocfs2_complete_recovery+0x17c1/0x25c0 fs/ocfs2/journal.c:1357
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3317
 worker_thread+0x870/0xd30 kernel/workqueue.c:3398
 kthread+0x7a9/0x920 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>


---
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Re: [syzbot] [ocfs2?] possible deadlock in ocfs2_finish_quota_recovery

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit:    b7f94fcf5546 Merge tag 'sched_ext-for-6.14-rc6-fixes' of g..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=113addb0580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=efbd4e7089941bb6
dashboard link: https://syzkaller.appspot.com/bug?extid=f59a1ae7b7227c859b8f
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1695e698580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=12a6e04c580000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-b7f94fcf.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/961a37fe09ad/vmlinux-b7f94fcf.xz
kernel image: https://storage.googleapis.com/syzbot-assets/483b4fd1ba55/bzImage-b7f94fcf.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/c0b6b6f0715a/mount_0.gz
  fsck result: OK (log: https://syzkaller.appspot.com/x/fsck.log?x=14a6e04c580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f59a1ae7b7227c859b8f@syzkaller.appspotmail.com

ocfs2: Finishing quota recovery on device (7,0) for slot 0
======================================================
WARNING: possible circular locking dependency detected
6.14.0-rc6-syzkaller-00022-gb7f94fcf5546 #0 Not tainted
------------------------------------------------------
kworker/u4:10/1087 is trying to acquire lock:
ffff88803c49e0e0 (&type->s_umount_key#42){++++}-{4:4}, at: ocfs2_finish_quota_recovery+0x15c/0x22a0 fs/ocfs2/quota_local.c:603

but task is already holding lock:
ffffc900026ffc60 ((work_completion)(&journal->j_recovery_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
ffffc900026ffc60 ((work_completion)(&journal->j_recovery_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9c6/0x18e0 kernel/workqueue.c:3319

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 ((work_completion)(&journal->j_recovery_work)){+.+.}-{0:0}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
       process_one_work kernel/workqueue.c:3214 [inline]
       process_scheduled_works+0x9e4/0x18e0 kernel/workqueue.c:3319
       worker_thread+0x870/0xd30 kernel/workqueue.c:3400
       kthread+0x7a9/0x920 kernel/kthread.c:464
       ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

-> #1 ((wq_completion)ocfs2_wq){+.+.}-{0:0}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
       touch_wq_lockdep_map+0xc7/0x170 kernel/workqueue.c:3907
       __flush_workqueue+0x14a/0x1280 kernel/workqueue.c:3949
       ocfs2_shutdown_local_alloc+0x109/0xa90 fs/ocfs2/localalloc.c:380
       ocfs2_dismount_volume+0x202/0x910 fs/ocfs2/super.c:1822
       generic_shutdown_super+0x139/0x2d0 fs/super.c:642
       kill_block_super+0x44/0x90 fs/super.c:1710
       deactivate_locked_super+0xc4/0x130 fs/super.c:473
       cleanup_mnt+0x41f/0x4b0 fs/namespace.c:1413
       task_work_run+0x24f/0x310 kernel/task_work.c:227
       resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
       exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
       exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
       __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
       syscall_exit_to_user_mode+0x13f/0x340 kernel/entry/common.c:218
       do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&type->s_umount_key#42){++++}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3163 [inline]
       check_prevs_add kernel/locking/lockdep.c:3282 [inline]
       validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3906
       __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5228
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
       down_read+0xb1/0xa40 kernel/locking/rwsem.c:1524
       ocfs2_finish_quota_recovery+0x15c/0x22a0 fs/ocfs2/quota_local.c:603
       ocfs2_complete_recovery+0x17c1/0x25c0 fs/ocfs2/journal.c:1357
       process_one_work kernel/workqueue.c:3238 [inline]
       process_scheduled_works+0xabe/0x18e0 kernel/workqueue.c:3319
       worker_thread+0x870/0xd30 kernel/workqueue.c:3400
       kthread+0x7a9/0x920 kernel/kthread.c:464
       ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

other info that might help us debug this:

Chain exists of:
  &type->s_umount_key#42 --> (wq_completion)ocfs2_wq --> (work_completion)(&journal->j_recovery_work)

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock((work_completion)(&journal->j_recovery_work));
                               lock((wq_completion)ocfs2_wq);
                               lock((work_completion)(&journal->j_recovery_work));
  rlock(&type->s_umount_key#42);

 *** DEADLOCK ***

2 locks held by kworker/u4:10/1087:
 #0: ffff8880403eb148 ((wq_completion)ocfs2_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
 #0: ffff8880403eb148 ((wq_completion)ocfs2_wq){+.+.}-{0:0}, at: process_scheduled_works+0x98b/0x18e0 kernel/workqueue.c:3319
 #1: ffffc900026ffc60 ((work_completion)(&journal->j_recovery_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #1: ffffc900026ffc60 ((work_completion)(&journal->j_recovery_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9c6/0x18e0 kernel/workqueue.c:3319

stack backtrace:
CPU: 0 UID: 0 PID: 1087 Comm: kworker/u4:10 Not tainted 6.14.0-rc6-syzkaller-00022-gb7f94fcf5546 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Workqueue: ocfs2_wq ocfs2_complete_recovery
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2076
 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2208
 check_prev_add kernel/locking/lockdep.c:3163 [inline]
 check_prevs_add kernel/locking/lockdep.c:3282 [inline]
 validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3906
 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5228
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
 down_read+0xb1/0xa40 kernel/locking/rwsem.c:1524
 ocfs2_finish_quota_recovery+0x15c/0x22a0 fs/ocfs2/quota_local.c:603
 ocfs2_complete_recovery+0x17c1/0x25c0 fs/ocfs2/journal.c:1357
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xabe/0x18e0 kernel/workqueue.c:3319
 worker_thread+0x870/0xd30 kernel/workqueue.c:3400
 kthread+0x7a9/0x920 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>


---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

Re: [syzbot] Re: [PATCH 0/3] ocfs2: Fix deadlocks in quota recovery

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com.

***

Subject: Re: [PATCH 0/3] ocfs2: Fix deadlocks in quota recovery
Author: heming.zhao@suse.com

I created a branch for these 3 patch files. Let's ask syzbot to test them.

syzbot page: https://syzkaller.appspot.com/bug?extid=f59a1ae7b7227c859b8f

#syz test: https://github.com/zhaohem/linux jans_ocfs2

On 4/3/25 19:32, Jan Kara wrote:
> Hello,
> 
> this implements another approach to fixing quota recovery deadlocks. We avoid
> grabbing sb->s_umount semaphore from ocfs2_finish_quota_recovery() and instead
> stop quota recovery early in ocfs2_dismount_volume(). Please review and test,
> the series has been only lightly tested in local mode as I don't have
> proper OCFS2 test setup.
> 
> 								Honza
> 

Re: [syzbot] [ocfs2?] possible deadlock in ocfs2_finish_quota_recovery

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
unregister_netdevice: waiting for DEV to become free

unregister_netdevice: waiting for batadv0 to become free. Usage count = 3


Tested on:

commit:         11376431 ocfs2: Stop quota recovery before disabling q..
git tree:       https://github.com/zhaohem/linux jans_ocfs2
console output: https://syzkaller.appspot.com/x/log.txt?x=14183a3f980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=5348e7fd1b89a770
dashboard link: https://syzkaller.appspot.com/bug?extid=f59a1ae7b7227c859b8f
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Note: no patches were applied.

Re: [syzbot] [ocfs2?] possible deadlock in ocfs2_finish_quota_recovery

[Heming Zhao]

On 4/17/25 12:21, syzbot wrote:
> Hello,
> 
> syzbot has tested the proposed patch but the reproducer is still triggering an issue:
> unregister_netdevice: waiting for DEV to become free
> 
> unregister_netdevice: waiting for batadv0 to become free. Usage count = 3

This is another module's issue, and the deadlock issue disappeared.

- Heming
> 
> 
> Tested on:
> 
> commit:         11376431 ocfs2: Stop quota recovery before disabling q..
> git tree:       https://github.com/zhaohem/linux jans_ocfs2
> console output: https://syzkaller.appspot.com/x/log.txt?x=14183a3f980000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=5348e7fd1b89a770
> dashboard link: https://syzkaller.appspot.com/bug?extid=f59a1ae7b7227c859b8f
> compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
> 
> Note: no patches were applied.