======================================================
WARNING: possible circular locking dependency detected
5.15.182-syzkaller #0 Not tainted
------------------------------------------------------
kworker/0:1H/150 is trying to acquire lock:
ffff888024d880e0 (&type->s_umount_key#59){+.+.}-{3:3}, at: freeze_super+0x44/0x420 fs/super.c:1696

but task is already holding lock:
ffffc900016ffd00 ((work_completion)(&(&gl->gl_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 ((work_completion)(&(&gl->gl_work)->work)){+.+.}-{0:0}:
       process_one_work+0x7bf/0x1000 kernel/workqueue.c:2286
       worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
       kthread+0x436/0x520 kernel/kthread.c:334
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

-> #1 ((wq_completion)glock_workqueue){+.+.}-{0:0}:
       flush_workqueue+0x142/0x1380 kernel/workqueue.c:2830
       gfs2_gl_hash_clear+0xa4/0x2f0 fs/gfs2/glock.c:2180
       gfs2_put_super+0x769/0x7d0 fs/gfs2/super.c:624
       generic_shutdown_super+0x130/0x300 fs/super.c:475
       kill_block_super+0x7c/0xe0 fs/super.c:1427
       deactivate_locked_super+0x93/0xf0 fs/super.c:335
       cleanup_mnt+0x418/0x4d0 fs/namespace.c:1143
       task_work_run+0x125/0x1a0 kernel/task_work.c:188
       tracehook_notify_resume include/linux/tracehook.h:189 [inline]
       exit_to_user_mode_loop+0x10f/0x130 kernel/entry/common.c:181
       exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214
       __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
       syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
       do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

-> #0 (&type->s_umount_key#59){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3053 [inline]
       check_prevs_add kernel/locking/lockdep.c:3172 [inline]
       validate_chain kernel/locking/lockdep.c:3788 [inline]
       __lock_acquire+0x2c33/0x7c60 kernel/locking/lockdep.c:5012
       lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
       down_write+0x38/0x60 kernel/locking/rwsem.c:1551
       freeze_super+0x44/0x420 fs/super.c:1696
       freeze_go_sync+0x179/0x340 fs/gfs2/glops.c:587
       do_xmote+0x387/0x1120 fs/gfs2/glock.c:742
       glock_work_func+0x25e/0x470 fs/gfs2/glock.c:1039
       process_one_work+0x863/0x1000 kernel/workqueue.c:2310
       worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
       kthread+0x436/0x520 kernel/kthread.c:334
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

other info that might help us debug this:

Chain exists of:
  &type->s_umount_key#59 --> (wq_completion)glock_workqueue --> (work_completion)(&(&gl->gl_work)->work)

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock((work_completion)(&(&gl->gl_work)->work));
                               lock((wq_completion)glock_workqueue);
                               lock((work_completion)(&(&gl->gl_work)->work));
  lock(&type->s_umount_key#59);

 *** DEADLOCK ***

2 locks held by kworker/0:1H/150:
 #0: ffff88814138b938 ((wq_completion)glock_workqueue){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc900016ffd00 ((work_completion)(&(&gl->gl_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285

stack backtrace:
CPU: 0 PID: 150 Comm: kworker/0:1H Not tainted 5.15.182-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
Workqueue: glock_workqueue glock_work_func
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 check_noncircular+0x274/0x310 kernel/locking/lockdep.c:2133
 check_prev_add kernel/locking/lockdep.c:3053 [inline]
 check_prevs_add kernel/locking/lockdep.c:3172 [inline]
 validate_chain kernel/locking/lockdep.c:3788 [inline]
 __lock_acquire+0x2c33/0x7c60 kernel/locking/lockdep.c:5012
 lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
 down_write+0x38/0x60 kernel/locking/rwsem.c:1551
 freeze_super+0x44/0x420 fs/super.c:1696
 freeze_go_sync+0x179/0x340 fs/gfs2/glops.c:587
 do_xmote+0x387/0x1120 fs/gfs2/glock.c:742
 glock_work_func+0x25e/0x470 fs/gfs2/glock.c:1039
 process_one_work+0x863/0x1000 kernel/workqueue.c:2310
 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>