======================================================
WARNING: possible circular locking dependency detected
5.15.149-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.0/3987 is trying to acquire lock:
ffff0000d9b71138 ((wq_completion)loop0){+.+.}-{0:0}, at: flush_workqueue+0x120/0x11c4 kernel/workqueue.c:2830

but task is already holding lock:
ffff0000cbd85468 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0xa8/0x9b8 drivers/block/loop.c:1365

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #6 (&lo->lo_mutex){+.+.}-{3:3}:
       __mutex_lock_common+0x194/0x2154 kernel/locking/mutex.c:596
       __mutex_lock kernel/locking/mutex.c:729 [inline]
       mutex_lock_killable_nested+0xa4/0xf8 kernel/locking/mutex.c:758
       lo_open+0x6c/0x14c drivers/block/loop.c:2055
       blkdev_get_whole+0x94/0x344 block/bdev.c:669
       blkdev_get_by_dev+0x238/0x89c block/bdev.c:824
       blkdev_open+0x10c/0x274 block/fops.c:463
       do_dentry_open+0x780/0xed8 fs/open.c:826
       vfs_open+0x7c/0x90 fs/open.c:956
       do_open fs/namei.c:3608 [inline]
       path_openat+0x1f28/0x26f0 fs/namei.c:3742
       do_filp_open+0x1a8/0x3b4 fs/namei.c:3769
       do_sys_openat2+0x128/0x3d8 fs/open.c:1211
       do_sys_open fs/open.c:1227 [inline]
       __do_sys_openat fs/open.c:1243 [inline]
       __se_sys_openat fs/open.c:1238 [inline]
       __arm64_sys_openat+0x1f0/0x240 fs/open.c:1238
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
       el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
       el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
       el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

-> #5 (&disk->open_mutex){+.+.}-{3:3}:
       __mutex_lock_common+0x194/0x2154 kernel/locking/mutex.c:596
       __mutex_lock kernel/locking/mutex.c:729 [inline]
       mutex_lock_nested+0xa4/0xf8 kernel/locking/mutex.c:743
       blkdev_get_by_dev+0x12c/0x89c block/bdev.c:817
       swsusp_check+0xb8/0x2dc kernel/power/swap.c:1526
       software_resume+0xe8/0x410 kernel/power/hibernate.c:977
       resume_store+0xe4/0x12c kernel/power/hibernate.c:1179
       kobj_attr_store+0x6c/0x90 lib/kobject.c:864
       sysfs_kf_write+0x200/0x280 fs/sysfs/file.c:139
       kernfs_fop_write_iter+0x334/0x48c fs/kernfs/file.c:296
       call_write_iter include/linux/fs.h:2146 [inline]
       new_sync_write fs/read_write.c:507 [inline]
       vfs_write+0x87c/0xb3c fs/read_write.c:594
       ksys_write+0x15c/0x26c fs/read_write.c:647
       __do_sys_write fs/read_write.c:659 [inline]
       __se_sys_write fs/read_write.c:656 [inline]
       __arm64_sys_write+0x7c/0x90 fs/read_write.c:656
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
       el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
       el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
       el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

-> #4 (system_transition_mutex/1){+.+.}-{3:3}:
       __mutex_lock_common+0x194/0x2154 kernel/locking/mutex.c:596
       __mutex_lock kernel/locking/mutex.c:729 [inline]
       mutex_lock_nested+0xa4/0xf8 kernel/locking/mutex.c:743
       software_resume+0x9c/0x410 kernel/power/hibernate.c:932
       resume_store+0xe4/0x12c kernel/power/hibernate.c:1179
       kobj_attr_store+0x6c/0x90 lib/kobject.c:864
       sysfs_kf_write+0x200/0x280 fs/sysfs/file.c:139
       kernfs_fop_write_iter+0x334/0x48c fs/kernfs/file.c:296
       call_write_iter include/linux/fs.h:2146 [inline]
       new_sync_write fs/read_write.c:507 [inline]
       vfs_write+0x87c/0xb3c fs/read_write.c:594
       ksys_write+0x15c/0x26c fs/read_write.c:647
       __do_sys_write fs/read_write.c:659 [inline]
       __se_sys_write fs/read_write.c:656 [inline]
       __arm64_sys_write+0x7c/0x90 fs/read_write.c:656
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
       el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
       el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
       el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

-> #3 (&of->mutex){+.+.}-{3:3}:
       __mutex_lock_common+0x194/0x2154 kernel/locking/mutex.c:596
       __mutex_lock kernel/locking/mutex.c:729 [inline]
       mutex_lock_nested+0xa4/0xf8 kernel/locking/mutex.c:743
       kernfs_seq_start+0x58/0x3a0 fs/kernfs/file.c:112
       seq_read_iter+0x378/0xc44 fs/seq_file.c:225
       kernfs_fop_read_iter+0x140/0x50c fs/kernfs/file.c:241
       call_read_iter include/linux/fs.h:2140 [inline]
       new_sync_read fs/read_write.c:404 [inline]
       vfs_read+0x86c/0xb10 fs/read_write.c:485
       ksys_read+0x15c/0x26c fs/read_write.c:623
       __do_sys_read fs/read_write.c:633 [inline]
       __se_sys_read fs/read_write.c:631 [inline]
       __arm64_sys_read+0x7c/0x90 fs/read_write.c:631
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
       el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
       el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
       el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

-> #2 (&p->lock){+.+.}-{3:3}:
       __mutex_lock_common+0x194/0x2154 kernel/locking/mutex.c:596
       __mutex_lock kernel/locking/mutex.c:729 [inline]
       mutex_lock_nested+0xa4/0xf8 kernel/locking/mutex.c:743
       seq_read_iter+0xac/0xc44 fs/seq_file.c:182
       kernfs_fop_read_iter+0x140/0x50c fs/kernfs/file.c:241
       do_iter_readv_writev+0x420/0x5f8
       do_iter_read+0x1c4/0x67c fs/read_write.c:790
       vfs_iter_read+0x88/0xac fs/read_write.c:832
       lo_read_simple drivers/block/loop.c:392 [inline]
       do_req_filebacked drivers/block/loop.c:663 [inline]
       loop_handle_cmd drivers/block/loop.c:2234 [inline]
       loop_process_work+0x19f0/0x2798 drivers/block/loop.c:2274
       loop_rootcg_workfn+0x28/0x38 drivers/block/loop.c:2305
       process_one_work+0x790/0x11b8 kernel/workqueue.c:2310
       worker_thread+0x910/0x1034 kernel/workqueue.c:2457
       kthread+0x37c/0x45c kernel/kthread.c:319
       ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:870

-> #1 ((work_completion)(&lo->rootcg_work)){+.+.}-{0:0}:
       process_one_work+0x6d4/0x11b8 kernel/workqueue.c:2286
       worker_thread+0x910/0x1034 kernel/workqueue.c:2457
       kthread+0x37c/0x45c kernel/kthread.c:319
       ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:870

-> #0 ((wq_completion)loop0){+.+.}-{0:0}:
       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+0x32d4/0x7638 kernel/locking/lockdep.c:5012
       lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5623
       flush_workqueue+0x14c/0x11c4 kernel/workqueue.c:2830
       drain_workqueue+0xb8/0x32c kernel/workqueue.c:2995
       destroy_workqueue+0x80/0xa34 kernel/workqueue.c:4439
       __loop_clr_fd+0x1c0/0x9b8 drivers/block/loop.c:1383
       loop_clr_fd drivers/block/loop.c:1509 [inline]
       lo_ioctl+0xe74/0x20d0 drivers/block/loop.c:1865
       blkdev_ioctl+0x3d8/0xbd0 block/ioctl.c:604
       block_ioctl+0xa8/0x114 block/fops.c:493
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:874 [inline]
       __se_sys_ioctl fs/ioctl.c:860 [inline]
       __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:860
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
       el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
       el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
       el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

other info that might help us debug this:

Chain exists of:
  (wq_completion)loop0 --> &disk->open_mutex --> &lo->lo_mutex

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&lo->lo_mutex);
                               lock(&disk->open_mutex);
                               lock(&lo->lo_mutex);
  lock((wq_completion)loop0);

 *** DEADLOCK ***

1 lock held by syz-executor.0/3987:
 #0: ffff0000cbd85468 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0xa8/0x9b8 drivers/block/loop.c:1365

stack backtrace:
CPU: 0 PID: 3987 Comm: syz-executor.0 Not tainted 5.15.149-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
Call trace:
 dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
 dump_stack+0x1c/0x58 lib/dump_stack.c:113
 print_circular_bug+0x150/0x1b8 kernel/locking/lockdep.c:2011
 check_noncircular+0x2cc/0x378 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+0x32d4/0x7638 kernel/locking/lockdep.c:5012
 lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5623
 flush_workqueue+0x14c/0x11c4 kernel/workqueue.c:2830
 drain_workqueue+0xb8/0x32c kernel/workqueue.c:2995
 destroy_workqueue+0x80/0xa34 kernel/workqueue.c:4439
 __loop_clr_fd+0x1c0/0x9b8 drivers/block/loop.c:1383
 loop_clr_fd drivers/block/loop.c:1509 [inline]
 lo_ioctl+0xe74/0x20d0 drivers/block/loop.c:1865
 blkdev_ioctl+0x3d8/0xbd0 block/ioctl.c:604
 block_ioctl+0xa8/0x114 block/fops.c:493
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl fs/ioctl.c:860 [inline]
 __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:860
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584