======================================================
WARNING: possible circular locking dependency detected
6.2.0-rc7-syzkaller-00091-g35674e787518 #0 Not tainted
------------------------------------------------------
kworker/1:1H/2560 is trying to acquire lock:
ffff88807f0420e0 (&type->s_umount_key#104){+.+.}-{3:3}, at: freeze_super+0x49/0x420 fs/super.c:1655

but task is already holding lock:
ffffc9000a5d7d20 ((work_completion)(&(&gl->gl_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7c6/0x1370 kernel/workqueue.c:2264

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}:
       lock_acquire+0x235/0x630 kernel/locking/lockdep.c:5668
       process_one_work+0x7e6/0x1370 kernel/workqueue.c:2265
       worker_thread+0xa63/0x1210 kernel/workqueue.c:2436
       kthread+0x270/0x300 kernel/kthread.c:376
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308

-> #1 ((wq_completion)glock_workqueue){+.+.}-{0:0}:
       lock_acquire+0x235/0x630 kernel/locking/lockdep.c:5668
       __flush_workqueue+0x178/0x1620 kernel/workqueue.c:2809
       gfs2_gl_hash_clear+0xa8/0x310 fs/gfs2/glock.c:2191
       gfs2_put_super+0x827/0x890 fs/gfs2/super.c:627
       generic_shutdown_super+0x134/0x310 fs/super.c:492
       kill_block_super+0x7e/0xe0 fs/super.c:1386
       deactivate_locked_super+0xa4/0x110 fs/super.c:332
       cleanup_mnt+0x490/0x520 fs/namespace.c:1291
       task_work_run+0x24a/0x300 kernel/task_work.c:179
       resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
       exit_to_user_mode_loop+0xd9/0x100 kernel/entry/common.c:171
       exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:203
       __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline]
       syscall_exit_to_user_mode+0x64/0x2e0 kernel/entry/common.c:296
       do_syscall_64+0x4d/0xc0 arch/x86/entry/common.c:86
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #0 (&type->s_umount_key#104){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3097 [inline]
       check_prevs_add kernel/locking/lockdep.c:3216 [inline]
       validate_chain+0x166b/0x58e0 kernel/locking/lockdep.c:3831
       __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5055
       lock_acquire+0x235/0x630 kernel/locking/lockdep.c:5668
       down_write+0x3a/0x60 kernel/locking/rwsem.c:1562
       freeze_super+0x49/0x420 fs/super.c:1655
       freeze_go_sync+0x17e/0x340 fs/gfs2/glops.c:577
       do_xmote+0x36f/0x1400 fs/gfs2/glock.c:708
       glock_work_func+0x2d9/0x460 fs/gfs2/glock.c:1056
       process_one_work+0x8fa/0x1370 kernel/workqueue.c:2289
       worker_thread+0xa63/0x1210 kernel/workqueue.c:2436
       kthread+0x270/0x300 kernel/kthread.c:376
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308

other info that might help us debug this:

Chain exists of:
  &type->s_umount_key#104 --> (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#104);

 *** DEADLOCK ***

2 locks held by kworker/1:1H/2560:
 #0: ffff888145ebb938 ((wq_completion)glock_workqueue){+.+.}-{0:0}, at: process_one_work+0x77f/0x1370
 #1: ffffc9000a5d7d20 ((work_completion)(&(&gl->gl_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7c6/0x1370 kernel/workqueue.c:2264

stack backtrace:
CPU: 1 PID: 2560 Comm: kworker/1:1H Not tainted 6.2.0-rc7-syzkaller-00091-g35674e787518 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/21/2023
Workqueue: glock_workqueue glock_work_func
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106
 check_noncircular+0x2fe/0x3b0 kernel/locking/lockdep.c:2177
 check_prev_add kernel/locking/lockdep.c:3097 [inline]
 check_prevs_add kernel/locking/lockdep.c:3216 [inline]
 validate_chain+0x166b/0x58e0 kernel/locking/lockdep.c:3831
 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5055
 lock_acquire+0x235/0x630 kernel/locking/lockdep.c:5668
 down_write+0x3a/0x60 kernel/locking/rwsem.c:1562
 freeze_super+0x49/0x420 fs/super.c:1655
 freeze_go_sync+0x17e/0x340 fs/gfs2/glops.c:577
 do_xmote+0x36f/0x1400 fs/gfs2/glock.c:708
 glock_work_func+0x2d9/0x460 fs/gfs2/glock.c:1056
 process_one_work+0x8fa/0x1370 kernel/workqueue.c:2289
 worker_thread+0xa63/0x1210 kernel/workqueue.c:2436
 kthread+0x270/0x300 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
 </TASK>