syzbot

gfs2: fsid=syz:syz.0: about to withdraw this file system
============================================
WARNING: possible recursive locking detected
5.15.184-syzkaller #0 Not tainted
--------------------------------------------
kworker/0:5/4220 is trying to acquire lock:
ffff8881411ff138 ((wq_completion)delete_workqueue){+.+.}-{0:0}, at: flush_workqueue+0x126/0x1380 kernel/workqueue.c:2830

but task is already holding lock:
ffff8881411ff138 ((wq_completion)delete_workqueue){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock((wq_completion)delete_workqueue);
  lock((wq_completion)delete_workqueue);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

2 locks held by kworker/0:5/4220:
 #0: ffff8881411ff138 ((wq_completion)delete_workqueue){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc9000318fd00 ((work_completion)(&(&gl->gl_delete)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285

stack backtrace:
CPU: 0 PID: 4220 Comm: kworker/0:5 Not tainted 5.15.184-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: delete_workqueue delete_work_func
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 __lock_acquire+0x1227/0x7c60 kernel/locking/lockdep.c:-1
 lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
 flush_workqueue+0x142/0x1380 kernel/workqueue.c:2830
 gfs2_make_fs_ro+0xd1/0x5d0 fs/gfs2/super.c:529
 signal_our_withdraw fs/gfs2/util.c:166 [inline]
 gfs2_withdraw+0x5f9/0x1460 fs/gfs2/util.c:343
 gfs2_meta_check_ii+0x6e/0x80 fs/gfs2/util.c:498
 gfs2_metatype_check_i fs/gfs2/util.h:126 [inline]
 gfs2_meta_buffer+0x232/0x310 fs/gfs2/meta_io.c:493
 gfs2_meta_inode_buffer fs/gfs2/meta_io.h:70 [inline]
 gfs2_inode_refresh+0xb5/0xfe0 fs/gfs2/glops.c:481
 gfs2_inode_lookup+0x839/0xd00 fs/gfs2/inode.c:199
 gfs2_lookup_by_inum+0x4e/0xf0 fs/gfs2/inode.c:250
 delete_work_func+0x17a/0x550 fs/gfs2/glock.c:1004
 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>