Warning: Permanently added '10.128.0.46' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 57.294930][ T8415] [ 57.297691][ T8415] ====================================================== [ 57.305343][ T8415] WARNING: possible circular locking dependency detected [ 57.312767][ T8415] 5.13.0-rc4-syzkaller #0 Not tainted [ 57.318109][ T8415] ------------------------------------------------------ [ 57.325202][ T8415] syz-executor018/8415 is trying to acquire lock: [ 57.331760][ T8415] ffff88801aae45a0 (&bdev->bd_mutex){+.+.}-{3:3}, at: del_gendisk+0x24b/0xa00 [ 57.341398][ T8415] [ 57.341398][ T8415] but task is already holding lock: [ 57.348750][ T8415] ffffffff8ca6db48 (loop_ctl_mutex){+.+.}-{3:3}, at: loop_control_ioctl+0x7b/0x4f0 [ 57.358031][ T8415] [ 57.358031][ T8415] which lock already depends on the new lock. [ 57.358031][ T8415] [ 57.368421][ T8415] [ 57.368421][ T8415] the existing dependency chain (in reverse order) is: [ 57.377411][ T8415] [ 57.377411][ T8415] -> #1 (loop_ctl_mutex){+.+.}-{3:3}: [ 57.384949][ T8415] __mutex_lock+0x139/0x10c0 [ 57.390052][ T8415] lo_open+0x1a/0x130 [ 57.394541][ T8415] __blkdev_get+0x182/0xa30 [ 57.399550][ T8415] blkdev_get_by_dev+0x200/0x660 [ 57.404992][ T8415] blkdev_open+0x154/0x2b0 [ 57.409914][ T8415] do_dentry_open+0x4b9/0x11b0 [ 57.415358][ T8415] path_openat+0x1c0e/0x27e0 [ 57.420455][ T8415] do_filp_open+0x190/0x3d0 [ 57.425463][ T8415] do_sys_openat2+0x16d/0x420 [ 57.430643][ T8415] __x64_sys_open+0x119/0x1c0 [ 57.435821][ T8415] do_syscall_64+0x3a/0xb0 [ 57.440743][ T8415] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 57.447143][ T8415] [ 57.447143][ T8415] -> #0 (&bdev->bd_mutex){+.+.}-{3:3}: [ 57.454938][ T8415] __lock_acquire+0x2a17/0x5230 [ 57.460298][ T8415] lock_acquire+0x1ab/0x740 [ 57.465308][ T8415] __mutex_lock+0x139/0x10c0 [ 57.470407][ T8415] del_gendisk+0x24b/0xa00 [ 57.475330][ T8415] loop_control_ioctl+0x40d/0x4f0 [ 57.480968][ T8415] __x64_sys_ioctl+0x193/0x200 [ 57.486322][ T8415] do_syscall_64+0x3a/0xb0 [ 57.491246][ T8415] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 57.497663][ T8415] [ 57.497663][ T8415] other info that might help us debug this: [ 57.497663][ T8415] [ 57.507869][ T8415] Possible unsafe locking scenario: [ 57.507869][ T8415] [ 57.515301][ T8415] CPU0 CPU1 [ 57.520644][ T8415] ---- ---- [ 57.525986][ T8415] lock(loop_ctl_mutex); [ 57.530472][ T8415] lock(&bdev->bd_mutex); [ 57.537404][ T8415] lock(loop_ctl_mutex); [ 57.544406][ T8415] lock(&bdev->bd_mutex); [ 57.548821][ T8415] [ 57.548821][ T8415] *** DEADLOCK *** [ 57.548821][ T8415] [ 57.556957][ T8415] 1 lock held by syz-executor018/8415: [ 57.562491][ T8415] #0: ffffffff8ca6db48 (loop_ctl_mutex){+.+.}-{3:3}, at: loop_control_ioctl+0x7b/0x4f0 [ 57.572229][ T8415] [ 57.572229][ T8415] stack backtrace: [ 57.578181][ T8415] CPU: 1 PID: 8415 Comm: syz-executor018 Not tainted 5.13.0-rc4-syzkaller #0 [ 57.586925][ T8415] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 57.596983][ T8415] Call Trace: [ 57.600246][ T8415] dump_stack+0x141/0x1d7 [ 57.604563][ T8415] check_noncircular+0x25f/0x2e0 [ 57.609492][ T8415] ? print_circular_bug+0x1e0/0x1e0 [ 57.614938][ T8415] ? lockdep_lock+0xc6/0x200 [ 57.619602][ T8415] ? call_rcu_zapped+0xb0/0xb0 [ 57.624351][ T8415] ? mark_held_locks+0x9f/0xe0 [ 57.629119][ T8415] __lock_acquire+0x2a17/0x5230 [ 57.633962][ T8415] ? lockdep_hardirqs_on_prepare+0x400/0x400 [ 57.639932][ T8415] lock_acquire+0x1ab/0x740 [ 57.644422][ T8415] ? del_gendisk+0x24b/0xa00 [ 57.649003][ T8415] ? lock_release+0x720/0x720 [ 57.653666][ T8415] ? find_held_lock+0x2d/0x110 [ 57.658417][ T8415] __mutex_lock+0x139/0x10c0 [ 57.662996][ T8415] ? del_gendisk+0x24b/0xa00 [ 57.667576][ T8415] ? mutex_lock_io_nested+0xf20/0xf20 [ 57.672954][ T8415] ? del_gendisk+0x24b/0xa00 [ 57.677533][ T8415] ? __mutex_unlock_slowpath+0xe2/0x610 [ 57.683069][ T8415] ? mutex_lock_io_nested+0xf20/0xf20 [ 57.688426][ T8415] ? wait_for_completion_io+0x270/0x270 [ 57.693960][ T8415] ? __sanitizer_cov_trace_const_cmp4+0x1c/0x70 [ 57.700206][ T8415] ? kernfs_remove_by_name_ns+0x62/0xb0 [ 57.705740][ T8415] ? sysfs_remove_files+0x87/0xf0 [ 57.710752][ T8415] del_gendisk+0x24b/0xa00 [ 57.715181][ T8415] loop_control_ioctl+0x40d/0x4f0 [ 57.720454][ T8415] ? loop_lookup+0x1d0/0x1d0 [ 57.725204][ T8415] ? __sanitizer_cov_trace_const_cmp4+0x1c/0x70 [ 57.731432][ T8415] ? loop_lookup+0x1d0/0x1d0 [ 57.736029][ T8415] __x64_sys_ioctl+0x193/0x200 [ 57.740794][ T8415] do_syscall_64+0x3a/0xb0 [ 57.745457][ T8415] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 57.751423][ T8415] RIP: 0033:0x43ee49 [ 57.755299][ T8415] Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48 [ 57.775760][ T8415] RSP: 002b:00007ffd6a55b098 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 57.784183][ T8415] RAX: ffffffffffffffda RBX: 0000000000400488 RCX: 000000000043ee49 [ 57.792138][ T8415] RDX: 0000000000000000 RSI: 0000000000004c81 RDI: 0000000000000003 [ 57.800091][ T8415] RBP: 0000000000402e30 R08: 0000000000000000 R09: 0000000000400488 [ 57.808325][ T8415] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402ec0 [ 57.816297][ T8415] R13: 0000000000000000 R14: 00000000004ac018 R15: 0000000000400488