======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Tainted: G             L     
------------------------------------------------------
kworker/u8:39/9634 is trying to acquire lock:
ffff88803fa95838 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xb8/0xe20 fs/seq_file.c:183

but task is already holding lock:
ffffc9000db7fc40 ((work_completion)(&worker->work)){+.+.}-{0:0}, at: process_one_work+0x8be/0x1630 kernel/workqueue.c:3294

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #5 ((work_completion)(&worker->work)){+.+.}-{0:0}:
       process_one_work+0x8d7/0x1630 kernel/workqueue.c:3294
       process_scheduled_works kernel/workqueue.c:3401 [inline]
       worker_thread+0xb49/0x1140 kernel/workqueue.c:3482
       kthread+0x388/0x470 kernel/kthread.c:436
       ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #4 ((wq_completion)loop2){+.+.}-{0:0}:
       touch_wq_lockdep_map+0xcb/0x180 kernel/workqueue.c:4033
       __flush_workqueue+0x14b/0x14f0 kernel/workqueue.c:4075
       drain_workqueue+0xd3/0x390 kernel/workqueue.c:4239
       __loop_clr_fd drivers/block/loop.c:1130 [inline]
       lo_release+0x287/0x8f0 drivers/block/loop.c:1767
       bdev_release+0x541/0x660 block/bdev.c:-1
       blkdev_release+0x15/0x20 block/fops.c:681
       __fput+0x461/0xa70 fs/file_table.c:510
       task_work_run+0x1d9/0x270 kernel/task_work.c:233
       exit_task_work include/linux/task_work.h:40 [inline]
       do_exit+0x70f/0x22c0 kernel/exit.c:1004
       do_group_exit+0x21b/0x2d0 kernel/exit.c:1147
       get_signal+0x1284/0x1330 kernel/signal.c:3038
       arch_do_signal_or_restart+0xbc/0x840 arch/x86/kernel/signal.c:337
       __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
       exit_to_user_mode_loop+0xa9/0x680 kernel/entry/common.c:98
       __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
       syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
       syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
       do_syscall_64+0x353/0x580 arch/x86/entry/syscall_64.c:100
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #3
 (&disk->open_mutex
#4
){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/rtmutex_api.c:559 [inline]
       mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:578
       bdev_open+0xe0/0xcc0 block/bdev.c:948
       bdev_file_open_by_dev+0x1be/0x240 block/bdev.c:1062
       swsusp_check+0x56/0x490 kernel/power/swap.c:1564
       software_resume+0x51/0x4c0 kernel/power/hibernate.c:1023
       resume_store+0x333/0x4f0 kernel/power/hibernate.c:1307
       kernfs_fop_write_iter+0x3b0/0x540 fs/kernfs/file.c:352
       new_sync_write fs/read_write.c:595 [inline]
       vfs_write+0x629/0xba0 fs/read_write.c:688
       ksys_write+0x156/0x270 fs/read_write.c:740
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #2 (
system_transition_mutex){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/rtmutex_api.c:559 [inline]
       mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:578
       lock_system_sleep+0x49/0x70 kernel/power/main.c:71
       resume_store+0x2ff/0x4f0 kernel/power/hibernate.c:1300
       kernfs_fop_write_iter+0x3b0/0x540 fs/kernfs/file.c:352
       new_sync_write fs/read_write.c:595 [inline]
       vfs_write+0x629/0xba0 fs/read_write.c:688
       ksys_write+0x156/0x270 fs/read_write.c:740
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (
&of->mutex){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/rtmutex_api.c:559 [inline]
       mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:578
       kernfs_seq_start+0x5c/0x420 fs/kernfs/file.c:172
       seq_read_iter+0x3f8/0xe20 fs/seq_file.c:226
       new_sync_read fs/read_write.c:493 [inline]
       vfs_read+0x58b/0xa80 fs/read_write.c:574
       ksys_read+0x156/0x270 fs/read_write.c:717
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&p->lock){+.+.}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3167 [inline]
       check_prevs_add kernel/locking/lockdep.c:3286 [inline]
       validate_chain kernel/locking/lockdep.c:3910 [inline]
       __lock_acquire+0x15a5/0x2d10 kernel/locking/lockdep.c:5239
       lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5870
       __mutex_lock_common kernel/locking/rtmutex_api.c:559 [inline]
       mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:578
       seq_read_iter+0xb8/0xe20 fs/seq_file.c:183
       lo_rw_aio+0xc80/0xf00 include/linux/percpu-rwsem.h:-1
       do_req_filebacked drivers/block/loop.c:435 [inline]
       loop_handle_cmd drivers/block/loop.c:1941 [inline]
       loop_process_work+0x92a/0x11b0 drivers/block/loop.c:1976
       process_one_work+0x98b/0x1630 kernel/workqueue.c:3318
       process_scheduled_works kernel/workqueue.c:3401 [inline]
       worker_thread+0xb49/0x1140 kernel/workqueue.c:3482
       kthread+0x388/0x470 kernel/kthread.c:436
       ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

other info that might help us debug this:

Chain exists of:
  &p->lock --> (wq_completion)loop2 --> (work_completion)(&worker->work)

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock((work_completion)(&worker->work));
                               lock((wq_completion)loop2);
                               lock((work_completion)(&worker->work));
  lock(&p->lock);

 *** DEADLOCK ***

2 locks held by kworker/u8:39/9634:
 #0: ffff88805d952138 ((wq_completion)loop9){+.+.}-{0:0}, at: process_one_work+0x897/0x1630 kernel/workqueue.c:3293
 #1: ffffc9000db7fc40 ((work_completion)(&worker->work)){+.+.}-{0:0}, at: process_one_work+0x8be/0x1630 kernel/workqueue.c:3294

stack backtrace:
CPU: 0 UID: 0 PID: 9634 Comm: kworker/u8:39 Tainted: G             L      syzkaller #0 PREEMPT_{RT,(full)} 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: loop9 loop_workfn
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2045
 check_noncircular+0x12e/0x150 kernel/locking/lockdep.c:2177
 check_prev_add kernel/locking/lockdep.c:3167 [inline]
 check_prevs_add kernel/locking/lockdep.c:3286 [inline]
 validate_chain kernel/locking/lockdep.c:3910 [inline]
 __lock_acquire+0x15a5/0x2d10 kernel/locking/lockdep.c:5239
 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5870
 __mutex_lock_common kernel/locking/rtmutex_api.c:559 [inline]
 mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:578
 seq_read_iter+0xb8/0xe20 fs/seq_file.c:183
 lo_rw_aio+0xc80/0xf00 include/linux/percpu-rwsem.h:-1
 do_req_filebacked drivers/block/loop.c:435 [inline]
 loop_handle_cmd drivers/block/loop.c:1941 [inline]
 loop_process_work+0x92a/0x11b0 drivers/block/loop.c:1976
 process_one_work+0x98b/0x1630 kernel/workqueue.c:3318
 process_scheduled_works kernel/workqueue.c:3401 [inline]
 worker_thread+0xb49/0x1140 kernel/workqueue.c:3482
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
------------[ cut here ]------------
in_task() && kcov_mode_enabled(mode)
WARNING: kernel/kcov.c:894 at kcov_remote_start+0x5d8/0x710 kernel/kcov.c:894, CPU#1: kworker/u8:39/9634
Modules linked in:
CPU: 1 UID: 0 PID: 9634 Comm: kworker/u8:39 Tainted: G             L      syzkaller #0 PREEMPT_{RT,(full)} 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: events_unbound cfg80211_wiphy_work
RIP: 0010:kcov_remote_start+0x5d8/0x710 kernel/kcov.c:894
Code: 00 5b 41 5c 41 5d 41 5e 41 5f 5d e9 42 a8 f2 02 90 0f 0b 90 e9 62 fa ff ff 90 0f 0b 90 0f b7 83 c0 04 00 00 e9 a3 fa ff ff 90 <0f> 0b 90 eb 04 90 0f 0b 90 e8 2a d7 74 09 89 c0 48 c7 c7 d0 b2 9a
RSP: 0018:ffffc9000db7fa38 EFLAGS: 00010202
RAX: 0000000000000002 RBX: ffff88805c555d00 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8bac2160 RDI: ffffffff8bac2120
RBP: ffff888024ec2280 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff1f5d99f R12: ffff88805d805e98
R13: ffff888063c607d8 R14: 0000000000000000 R15: ffff88805d805000
FS:  0000000000000000(0000) GS:ffff888125d7e000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffd927d8c80 CR3: 000000001191c000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 kcov_remote_start_common include/linux/kcov.h:48 [inline]
 ieee80211_iface_work+0x20e/0x1020 net/mac80211/iface.c:1806
 cfg80211_wiphy_work+0x2cf/0x460 net/wireless/core.c:538
 process_one_work+0x98b/0x1630 kernel/workqueue.c:3318
 process_scheduled_works kernel/workqueue.c:3401 [inline]
 worker_thread+0xb49/0x1140 kernel/workqueue.c:3482
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>