====================================================== WARNING: possible circular locking dependency detected 5.18.0-rc7-syzkaller-00164-g6c3f5bec9b40 #0 Not tainted ------------------------------------------------------ udevd/4708 is trying to acquire lock: ffff888075cf2138 ((wq_completion)loop4){+.+.}-{0:0}, at: flush_workqueue+0x170/0x16a0 kernel/workqueue.c:2809 but task is already holding lock: ffff88801c2bb118 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xf8/0x790 block/bdev.c:905 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #6 (&disk->open_mutex){+.+.}-{3:3}: lock_acquire+0x1a7/0x400 kernel/locking/lockdep.c:5641 __mutex_lock_common+0x1de/0x26e0 kernel/locking/mutex.c:600 __mutex_lock kernel/locking/mutex.c:733 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:785 blkdev_get_by_dev+0xfd/0xa30 block/bdev.c:807 swsusp_check+0xb0/0x400 kernel/power/swap.c:1524 software_resume+0xc8/0x3c0 kernel/power/hibernate.c:980 resume_store+0xdc/0x120 kernel/power/hibernate.c:1182 kernfs_fop_write_iter+0x3ac/0x500 fs/kernfs/file.c:291 call_write_iter include/linux/fs.h:2050 [inline] new_sync_write fs/read_write.c:504 [inline] vfs_write+0xa22/0xd40 fs/read_write.c:591 ksys_write+0x19b/0x2c0 fs/read_write.c:644 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae -> #5 (system_transition_mutex/1){+.+.}-{3:3}: lock_acquire+0x1a7/0x400 kernel/locking/lockdep.c:5641 __mutex_lock_common+0x1de/0x26e0 kernel/locking/mutex.c:600 __mutex_lock kernel/locking/mutex.c:733 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:785 software_resume+0x7a/0x3c0 kernel/power/hibernate.c:935 resume_store+0xdc/0x120 kernel/power/hibernate.c:1182 kernfs_fop_write_iter+0x3ac/0x500 fs/kernfs/file.c:291 call_write_iter include/linux/fs.h:2050 [inline] new_sync_write fs/read_write.c:504 [inline] vfs_write+0xa22/0xd40 fs/read_write.c:591 ksys_write+0x19b/0x2c0 fs/read_write.c:644 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae -> #4 (&of->mutex){+.+.}-{3:3}: lock_acquire+0x1a7/0x400 kernel/locking/lockdep.c:5641 __mutex_lock_common+0x1de/0x26e0 kernel/locking/mutex.c:600 __mutex_lock kernel/locking/mutex.c:733 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:785 kernfs_seq_start+0x4f/0x3a0 fs/kernfs/file.c:112 seq_read_iter+0x3cd/0xd30 fs/seq_file.c:225 call_read_iter include/linux/fs.h:2044 [inline] new_sync_read fs/read_write.c:401 [inline] vfs_read+0xa01/0xd10 fs/read_write.c:482 ksys_read+0x19b/0x2c0 fs/read_write.c:620 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae -> #3 (&p->lock){+.+.}-{3:3}: lock_acquire+0x1a7/0x400 kernel/locking/lockdep.c:5641 __mutex_lock_common+0x1de/0x26e0 kernel/locking/mutex.c:600 __mutex_lock kernel/locking/mutex.c:733 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:785 seq_read_iter+0xad/0xd30 fs/seq_file.c:182 call_read_iter include/linux/fs.h:2044 [inline] generic_file_splice_read+0x3c0/0x660 fs/splice.c:311 do_splice_to fs/splice.c:796 [inline] splice_direct_to_actor+0x450/0xc20 fs/splice.c:870 do_splice_direct+0x2a0/0x3f0 fs/splice.c:979 do_sendfile+0x623/0xf90 fs/read_write.c:1246 __do_sys_sendfile64 fs/read_write.c:1311 [inline] __se_sys_sendfile64+0x178/0x1e0 fs/read_write.c:1297 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae -> #2 (sb_writers#5){.+.+}-{0:0}: lock_acquire+0x1a7/0x400 kernel/locking/lockdep.c:5641 percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1698 [inline] sb_start_write include/linux/fs.h:1768 [inline] file_start_write include/linux/fs.h:2785 [inline] lo_write_bvec drivers/block/loop.c:244 [inline] lo_write_simple drivers/block/loop.c:267 [inline] do_req_filebacked drivers/block/loop.c:494 [inline] loop_handle_cmd drivers/block/loop.c:1870 [inline] loop_process_work+0x16a0/0x22f0 drivers/block/loop.c:1910 process_one_work+0x81c/0xd10 kernel/workqueue.c:2289 worker_thread+0xb14/0x1330 kernel/workqueue.c:2436 kthread+0x266/0x300 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 -> #1 ((work_completion)(&lo->rootcg_work)){+.+.}-{0:0}: lock_acquire+0x1a7/0x400 kernel/locking/lockdep.c:5641 process_one_work+0x7f1/0xd10 kernel/workqueue.c:2265 worker_thread+0xb14/0x1330 kernel/workqueue.c:2436 kthread+0x266/0x300 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 -> #0 ((wq_completion)loop4){+.+.}-{0:0}: check_prev_add kernel/locking/lockdep.c:3065 [inline] check_prevs_add kernel/locking/lockdep.c:3188 [inline] validate_chain+0x185c/0x65c0 kernel/locking/lockdep.c:3803 __lock_acquire+0x129a/0x1f80 kernel/locking/lockdep.c:5029 lock_acquire+0x1a7/0x400 kernel/locking/lockdep.c:5641 flush_workqueue+0x18c/0x16a0 kernel/workqueue.c:2809 drain_workqueue+0xc3/0x3a0 kernel/workqueue.c:2974 destroy_workqueue+0x7d/0xed0 kernel/workqueue.c:4411 __loop_clr_fd+0x1bc/0x930 drivers/block/loop.c:1123 blkdev_put+0x5a1/0x790 blkdev_close+0x55/0x80 block/fops.c:512 __fput+0x3b9/0x820 fs/file_table.c:317 task_work_run+0x146/0x1c0 kernel/task_work.c:164 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0x134/0x160 kernel/entry/common.c:169 exit_to_user_mode_prepare+0xad/0x110 kernel/entry/common.c:201 __syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline] syscall_exit_to_user_mode+0x2e/0x70 kernel/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x44/0xae other info that might help us debug this: Chain exists of: (wq_completion)loop4 --> system_transition_mutex/1 --> &disk->open_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&disk->open_mutex); lock(system_transition_mutex/1); lock(&disk->open_mutex); lock((wq_completion)loop4); *** DEADLOCK *** 1 lock held by udevd/4708: #0: ffff88801c2bb118 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xf8/0x790 block/bdev.c:905 stack backtrace: CPU: 1 PID: 4708 Comm: udevd Not tainted 5.18.0-rc7-syzkaller-00164-g6c3f5bec9b40 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106 check_noncircular+0x2f7/0x3b0 kernel/locking/lockdep.c:2145 check_prev_add kernel/locking/lockdep.c:3065 [inline] check_prevs_add kernel/locking/lockdep.c:3188 [inline] validate_chain+0x185c/0x65c0 kernel/locking/lockdep.c:3803 __lock_acquire+0x129a/0x1f80 kernel/locking/lockdep.c:5029 lock_acquire+0x1a7/0x400 kernel/locking/lockdep.c:5641 flush_workqueue+0x18c/0x16a0 kernel/workqueue.c:2809 drain_workqueue+0xc3/0x3a0 kernel/workqueue.c:2974 destroy_workqueue+0x7d/0xed0 kernel/workqueue.c:4411 __loop_clr_fd+0x1bc/0x930 drivers/block/loop.c:1123 blkdev_put+0x5a1/0x790 blkdev_close+0x55/0x80 block/fops.c:512 __fput+0x3b9/0x820 fs/file_table.c:317 task_work_run+0x146/0x1c0 kernel/task_work.c:164 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0x134/0x160 kernel/entry/common.c:169 exit_to_user_mode_prepare+0xad/0x110 kernel/entry/common.c:201 __syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline] syscall_exit_to_user_mode+0x2e/0x70 kernel/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7eff87125fc3 Code: 48 ff ff ff b8 ff ff ff ff e9 3e ff ff ff 66 0f 1f 84 00 00 00 00 00 64 8b 04 25 18 00 00 00 85 c0 75 14 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 45 c3 0f 1f 40 00 48 83 ec 18 89 7c 24 0c e8 RSP: 002b:00007ffe9f9c1258 EFLAGS: 00000246 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 00007eff875cc6a8 RCX: 00007eff87125fc3 RDX: 000000000000001c RSI: 00007ffe9f9c0a58 RDI: 0000000000000008 RBP: 000055b11cdafc10 R08: 0000000000000007 R09: 000055b11cda6340 R10: 000000000158f23a R11: 0000000000000246 R12: 0000000000000002 R13: 000055b11cd84b70 R14: 0000000000000008 R15: 000055b11cd7b910 BTRFS: device fsid 43710d19-c345-4339-9143-01e5730e13f9 devid 1 transid 7 /dev/loop2 scanned by udevd (4708)