[ OK ] Started Getty on tty2. Starting Load/Save RF Kill Switch Status... [ OK ] Started Getty on tty1. [ OK ] Started Serial Getty on ttyS0. [ OK ] Reached target Login Prompts. [ OK ] Reached target Multi-User System. [ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... [ OK ] Started Load/Save RF Kill Switch Status. [ OK ] Started Update UTMP about System Runlevel Changes. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.0.66' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program syzkaller login: [ 74.905047][ T8679] [ 74.907617][ T8679] ====================================================== [ 74.914613][ T8679] WARNING: possible circular locking dependency detected [ 74.921614][ T8679] 5.13.0-rc5-syzkaller #0 Not tainted [ 74.926977][ T8679] ------------------------------------------------------ [ 74.933988][ T8679] systemd-udevd/8679 is trying to acquire lock: [ 74.940207][ T8679] ffffffff8ca6de28 (loop_ctl_mutex){+.+.}-{3:3}, at: loop_probe+0xc7/0x150 [ 74.948836][ T8679] [ 74.948836][ T8679] but task is already holding lock: [ 74.956207][ T8679] ffffffff8c7e03a8 (major_names_lock){+.+.}-{3:3}, at: blk_request_module+0x25/0x1d0 [ 74.965795][ T8679] [ 74.965795][ T8679] which lock already depends on the new lock. [ 74.965795][ T8679] [ 74.976210][ T8679] [ 74.976210][ T8679] the existing dependency chain (in reverse order) is: [ 74.985226][ T8679] [ 74.985226][ T8679] -> #3 (major_names_lock){+.+.}-{3:3}: [ 74.992958][ T8679] __mutex_lock+0x139/0x10c0 [ 74.998088][ T8679] __register_blkdev+0x2b/0x3e0 [ 75.003447][ T8679] register_mtd_blktrans+0x85/0x3c0 [ 75.009207][ T8679] do_one_initcall+0x103/0x650 [ 75.014490][ T8679] kernel_init_freeable+0x6c4/0x74d [ 75.020219][ T8679] kernel_init+0xd/0x1b8 [ 75.024969][ T8679] ret_from_fork+0x1f/0x30 [ 75.029910][ T8679] [ 75.029910][ T8679] -> #2 (mtd_table_mutex){+.+.}-{3:3}: [ 75.037534][ T8679] __mutex_lock+0x139/0x10c0 [ 75.042653][ T8679] blktrans_open+0x69/0x600 [ 75.047667][ T8679] __blkdev_get+0x182/0xa30 [ 75.052676][ T8679] blkdev_get_by_dev+0x200/0x660 [ 75.058120][ T8679] blkdev_open+0x154/0x2b0 [ 75.063150][ T8679] do_dentry_open+0x4b9/0x11b0 [ 75.068423][ T8679] path_openat+0x1c0e/0x27e0 [ 75.073534][ T8679] do_filp_open+0x190/0x3d0 [ 75.078545][ T8679] do_sys_openat2+0x16d/0x420 [ 75.083736][ T8679] __x64_sys_open+0x119/0x1c0 [ 75.088926][ T8679] do_syscall_64+0x3a/0xb0 [ 75.093855][ T8679] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 75.100270][ T8679] [ 75.100270][ T8679] -> #1 (&bdev->bd_mutex){+.+.}-{3:3}: [ 75.107894][ T8679] __mutex_lock+0x139/0x10c0 [ 75.113008][ T8679] del_gendisk+0x24b/0xa00 [ 75.117946][ T8679] loop_control_ioctl+0x3e7/0x4c0 [ 75.123481][ T8679] __do_compat_sys_ioctl+0x1c7/0x290 [ 75.129278][ T8679] __do_fast_syscall_32+0x67/0xe0 [ 75.134831][ T8679] do_fast_syscall_32+0x2f/0x70 [ 75.140224][ T8679] entry_SYSENTER_compat_after_hwframe+0x4d/0x5c [ 75.147081][ T8679] [ 75.147081][ T8679] -> #0 (loop_ctl_mutex){+.+.}-{3:3}: [ 75.154620][ T8679] __lock_acquire+0x2a17/0x5230 [ 75.160005][ T8679] lock_acquire+0x1ab/0x740 [ 75.165026][ T8679] __mutex_lock+0x139/0x10c0 [ 75.170134][ T8679] loop_probe+0xc7/0x150 [ 75.174908][ T8679] blk_request_module+0x111/0x1d0 [ 75.180468][ T8679] blkdev_get_no_open+0x1d8/0x250 [ 75.186014][ T8679] blkdev_get_by_dev+0x76/0x660 [ 75.191387][ T8679] blkdev_open+0x154/0x2b0 [ 75.196340][ T8679] do_dentry_open+0x4b9/0x11b0 [ 75.201629][ T8679] path_openat+0x1c0e/0x27e0 [ 75.206728][ T8679] do_filp_open+0x190/0x3d0 [ 75.211739][ T8679] do_sys_openat2+0x16d/0x420 [ 75.216920][ T8679] __x64_sys_open+0x119/0x1c0 [ 75.222105][ T8679] do_syscall_64+0x3a/0xb0 [ 75.227048][ T8679] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 75.233450][ T8679] [ 75.233450][ T8679] other info that might help us debug this: [ 75.233450][ T8679] [ 75.243957][ T8679] Chain exists of: [ 75.243957][ T8679] loop_ctl_mutex --> mtd_table_mutex --> major_names_lock [ 75.243957][ T8679] [ 75.256966][ T8679] Possible unsafe locking scenario: [ 75.256966][ T8679] [ 75.264399][ T8679] CPU0 CPU1 [ 75.269744][ T8679] ---- ---- [ 75.275102][ T8679] lock(major_names_lock); [ 75.279605][ T8679] lock(mtd_table_mutex); [ 75.286521][ T8679] lock(major_names_lock); [ 75.293522][ T8679] lock(loop_ctl_mutex); [ 75.297979][ T8679] [ 75.297979][ T8679] *** DEADLOCK *** [ 75.297979][ T8679] [ 75.306103][ T8679] 1 lock held by systemd-udevd/8679: [ 75.311367][ T8679] #0: ffffffff8c7e03a8 (major_names_lock){+.+.}-{3:3}, at: blk_request_module+0x25/0x1d0 [ 75.321271][ T8679] [ 75.321271][ T8679] stack backtrace: [ 75.327152][ T8679] CPU: 0 PID: 8679 Comm: systemd-udevd Not tainted 5.13.0-rc5-syzkaller #0 [ 75.335721][ T8679] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 75.345801][ T8679] Call Trace: [ 75.349073][ T8679] dump_stack+0x141/0x1d7 [ 75.353410][ T8679] check_noncircular+0x25f/0x2e0 [ 75.358396][ T8679] ? print_circular_bug+0x1e0/0x1e0 [ 75.363587][ T8679] ? mark_lock+0xef/0x17b0 [ 75.368094][ T8679] ? lockdep_lock+0xc6/0x200 [ 75.372691][ T8679] ? call_rcu_zapped+0xb0/0xb0 [ 75.377442][ T8679] ? tomoyo_check_open_permission+0x172/0x380 [ 75.383509][ T8679] ? security_file_open+0x52/0x4f0 [ 75.388612][ T8679] __lock_acquire+0x2a17/0x5230 [ 75.393454][ T8679] ? lockdep_hardirqs_on_prepare+0x400/0x400 [ 75.399426][ T8679] lock_acquire+0x1ab/0x740 [ 75.403934][ T8679] ? loop_probe+0xc7/0x150 [ 75.408339][ T8679] ? lock_release+0x720/0x720 [ 75.413011][ T8679] __mutex_lock+0x139/0x10c0 [ 75.417611][ T8679] ? loop_probe+0xc7/0x150 [ 75.422022][ T8679] ? loop_probe+0xc7/0x150 [ 75.426425][ T8679] ? mutex_lock_io_nested+0xf20/0xf20 [ 75.431785][ T8679] ? __mutex_lock+0x5d5/0x10c0 [ 75.436575][ T8679] ? blk_request_module+0x25/0x1d0 [ 75.441692][ T8679] ? find_held_lock+0x2d/0x110 [ 75.446442][ T8679] ? mutex_lock_io_nested+0xf20/0xf20 [ 75.451820][ T8679] ? ilookup+0xb3/0x230 [ 75.455984][ T8679] loop_probe+0xc7/0x150 [ 75.460215][ T8679] ? loop_control_ioctl+0x4c0/0x4c0 [ 75.465421][ T8679] ? find_inode_fast+0x16f/0x220 [ 75.470366][ T8679] ? do_raw_spin_unlock+0x171/0x230 [ 75.475569][ T8679] ? loop_control_ioctl+0x4c0/0x4c0 [ 75.480754][ T8679] blk_request_module+0x111/0x1d0 [ 75.485884][ T8679] blkdev_get_no_open+0x1d8/0x250 [ 75.490907][ T8679] blkdev_get_by_dev+0x76/0x660 [ 75.495750][ T8679] blkdev_open+0x154/0x2b0 [ 75.500164][ T8679] do_dentry_open+0x4b9/0x11b0 [ 75.504918][ T8679] ? blkdev_get_by_dev+0x660/0x660 [ 75.510019][ T8679] ? may_open+0x1f6/0x420 [ 75.514348][ T8679] path_openat+0x1c0e/0x27e0 [ 75.518941][ T8679] ? path_lookupat+0x850/0x850 [ 75.523692][ T8679] ? lockdep_hardirqs_on_prepare+0x400/0x400 [ 75.529662][ T8679] do_filp_open+0x190/0x3d0 [ 75.534153][ T8679] ? may_open_dev+0xf0/0xf0 [ 75.538653][ T8679] ? do_raw_spin_lock+0x120/0x2b0 [ 75.543667][ T8679] ? rwlock_bug.part.0+0x90/0x90 [ 75.548589][ T8679] ? __sanitizer_cov_trace_const_cmp8+0x1d/0x70 [ 75.554819][ T8679] ? _find_next_bit+0x1e3/0x260 [ 75.559658][ T8679] ? _raw_spin_unlock+0x24/0x40 [ 75.564492][ T8679] ? alloc_fd+0x2e6/0x660 [ 75.568807][ T8679] do_sys_openat2+0x16d/0x420 [ 75.573486][ T8679] ? build_open_flags+0x6f0/0x6f0 [ 75.578506][ T8679] ? __context_tracking_exit+0xb8/0xe0 [ 75.583965][ T8679] __x64_sys_open+0x119/0x1c0 [ 75.588643][ T8679] ? do_sys_open+0x140/0x140 [ 75.593219][ T8679] ? __secure_computing+0x104/0x360 [ 75.598405][ T8679] do_syscall_64+0x3a/0xb0 [ 75.602808][ T8679] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 75.608686][ T8679] RIP: 0033:0x7f5e2952d840 [ 75.613085][ T8679] Code: 73 01 c3 48 8b 0d 68 77 20 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 83 3d 89 bb 20 00 00 75 10 b8 02 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 1e f6 ff ff 48 89 04 24 [ 75.632676][ T8679] RSP: 002b:00007ffdb38a5c08 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 [ 75.641071][ T8679] RAX: ffffffffffffffda RBX: 00005644180a18f0 RCX: 00007f5e2952d840 [ 75.649026][ T8679] RDX: 0000564417c00fe3 RSI: 00000000000a0800 RDI: 00005644180a1830 [ 75.657009][ T8679] RBP: 00007ffdb38a5d80 R08: 0000564417c00670 R09: 0000000000000010 [ 75.664973][ T8679] R10: 0000564417c00d0c R11: 0000000000000246 R12: 00007ffdb38a5cd0 [ 75.672940][ T8679] R13: 00005644180a3010 R14: 0000000000000003 R15: 000000000000000e executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program