[ 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 Update UTMP about System Runlevel Changes. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.0.255' (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 syzkaller login: [ 73.316070][ T8573] [ 73.318425][ T8573] ====================================================== [ 73.325522][ T8573] WARNING: possible circular locking dependency detected [ 73.332726][ T8573] 5.14.0-rc5-syzkaller #0 Not tainted [ 73.338073][ T8573] ------------------------------------------------------ [ 73.345066][ T8573] systemd-udevd/8573 is trying to acquire lock: [ 73.351464][ T8573] ffffffff8c486b88 (loop_ctl_mutex){+.+.}-{3:3}, at: loop_add+0x9c/0x8c0 [ 73.360009][ T8573] [ 73.360009][ T8573] but task is already holding lock: [ 73.367525][ T8573] ffffffff8c1f3fe8 (major_names_lock){+.+.}-{3:3}, at: blk_request_module+0x25/0x1d0 [ 73.376986][ T8573] [ 73.376986][ T8573] which lock already depends on the new lock. [ 73.376986][ T8573] [ 73.387381][ T8573] [ 73.387381][ T8573] the existing dependency chain (in reverse order) is: [ 73.396370][ T8573] [ 73.396370][ T8573] -> #3 (major_names_lock){+.+.}-{3:3}: [ 73.404184][ T8573] __mutex_lock+0x12a/0x10a0 [ 73.409319][ T8573] __register_blkdev+0x2b/0x3e0 [ 73.414686][ T8573] register_mtd_blktrans+0x85/0x3c0 [ 73.420403][ T8573] do_one_initcall+0x103/0x650 [ 73.425676][ T8573] kernel_init_freeable+0x6b8/0x741 [ 73.431397][ T8573] kernel_init+0x1a/0x1d0 [ 73.436353][ T8573] ret_from_fork+0x1f/0x30 [ 73.441275][ T8573] [ 73.441275][ T8573] -> #2 (mtd_table_mutex){+.+.}-{3:3}: [ 73.448986][ T8573] __mutex_lock+0x12a/0x10a0 [ 73.454086][ T8573] blktrans_open+0x69/0x600 [ 73.459100][ T8573] blkdev_get_whole+0xa1/0x420 [ 73.464363][ T8573] blkdev_get_by_dev.part.0+0x30c/0xdd0 [ 73.470581][ T8573] blkdev_open+0x295/0x300 [ 73.475584][ T8573] do_dentry_open+0x4c8/0x11d0 [ 73.480902][ T8573] path_openat+0x1c23/0x27f0 [ 73.486002][ T8573] do_filp_open+0x1aa/0x400 [ 73.491016][ T8573] do_sys_openat2+0x16d/0x420 [ 73.496209][ T8573] __x64_sys_open+0x119/0x1c0 [ 73.501395][ T8573] do_syscall_64+0x35/0xb0 [ 73.506593][ T8573] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 73.512997][ T8573] [ 73.512997][ T8573] -> #1 (&disk->open_mutex){+.+.}-{3:3}: [ 73.520818][ T8573] __mutex_lock+0x12a/0x10a0 [ 73.526259][ T8573] del_gendisk+0x8b/0x770 [ 73.531311][ T8573] loop_control_ioctl+0x3b5/0x450 [ 73.537127][ T8573] __do_compat_sys_ioctl+0x1c7/0x290 [ 73.542920][ T8573] __do_fast_syscall_32+0x65/0xf0 [ 73.548464][ T8573] do_fast_syscall_32+0x2f/0x70 [ 73.554178][ T8573] entry_SYSENTER_compat_after_hwframe+0x4d/0x5c [ 73.561008][ T8573] [ 73.561008][ T8573] -> #0 (loop_ctl_mutex){+.+.}-{3:3}: [ 73.568556][ T8573] __lock_acquire+0x2a07/0x54a0 [ 73.573912][ T8573] lock_acquire+0x1ab/0x510 [ 73.578917][ T8573] __mutex_lock+0x12a/0x10a0 [ 73.584022][ T8573] loop_add+0x9c/0x8c0 [ 73.588703][ T8573] loop_probe+0x6a/0x80 [ 73.593361][ T8573] blk_request_module+0x111/0x1d0 [ 73.598891][ T8573] blkdev_get_no_open+0x1d5/0x250 [ 73.604416][ T8573] blkdev_get_by_dev.part.0+0x25/0xdd0 [ 73.610467][ T8573] blkdev_open+0x295/0x300 [ 73.615397][ T8573] do_dentry_open+0x4c8/0x11d0 [ 73.620847][ T8573] path_openat+0x1c23/0x27f0 [ 73.625952][ T8573] do_filp_open+0x1aa/0x400 [ 73.631128][ T8573] do_sys_openat2+0x16d/0x420 [ 73.636306][ T8573] __x64_sys_open+0x119/0x1c0 [ 73.641490][ T8573] do_syscall_64+0x35/0xb0 [ 73.646428][ T8573] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 73.652833][ T8573] [ 73.652833][ T8573] other info that might help us debug this: [ 73.652833][ T8573] [ 73.663036][ T8573] Chain exists of: [ 73.663036][ T8573] loop_ctl_mutex --> mtd_table_mutex --> major_names_lock [ 73.663036][ T8573] [ 73.676219][ T8573] Possible unsafe locking scenario: [ 73.676219][ T8573] [ 73.683740][ T8573] CPU0 CPU1 [ 73.689095][ T8573] ---- ---- [ 73.694434][ T8573] lock(major_names_lock); [ 73.698924][ T8573] lock(mtd_table_mutex); [ 73.705838][ T8573] lock(major_names_lock); [ 73.712834][ T8573] lock(loop_ctl_mutex); [ 73.717138][ T8573] [ 73.717138][ T8573] *** DEADLOCK *** [ 73.717138][ T8573] [ 73.725699][ T8573] 1 lock held by systemd-udevd/8573: [ 73.731056][ T8573] #0: ffffffff8c1f3fe8 (major_names_lock){+.+.}-{3:3}, at: blk_request_module+0x25/0x1d0 [ 73.740954][ T8573] [ 73.740954][ T8573] stack backtrace: [ 73.746923][ T8573] CPU: 1 PID: 8573 Comm: systemd-udevd Not tainted 5.14.0-rc5-syzkaller #0 [ 73.755575][ T8573] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 73.765698][ T8573] Call Trace: [ 73.769307][ T8573] dump_stack_lvl+0xcd/0x134 [ 73.773888][ T8573] check_noncircular+0x25f/0x2e0 [ 73.778821][ T8573] ? lockdep_hardirqs_on_prepare+0x400/0x400 [ 73.784894][ T8573] ? print_circular_bug+0x1e0/0x1e0 [ 73.790076][ T8573] ? lock_chain_count+0x20/0x20 [ 73.794911][ T8573] ? lockdep_lock+0xc6/0x200 [ 73.799487][ T8573] ? call_rcu_zapped+0xb0/0xb0 [ 73.804328][ T8573] __lock_acquire+0x2a07/0x54a0 [ 73.809178][ T8573] ? lockdep_hardirqs_on_prepare+0x400/0x400 [ 73.815146][ T8573] lock_acquire+0x1ab/0x510 [ 73.819629][ T8573] ? loop_add+0x9c/0x8c0 [ 73.823858][ T8573] ? lock_release+0x720/0x720 [ 73.828515][ T8573] ? path_openat+0x1c23/0x27f0 [ 73.833281][ T8573] ? do_filp_open+0x1aa/0x400 [ 73.838112][ T8573] ? do_sys_openat2+0x16d/0x420 [ 73.842949][ T8573] ? __x64_sys_open+0x119/0x1c0 [ 73.847789][ T8573] __mutex_lock+0x12a/0x10a0 [ 73.852368][ T8573] ? loop_add+0x9c/0x8c0 [ 73.856687][ T8573] ? loop_add+0x9c/0x8c0 [ 73.860927][ T8573] ? mutex_lock_io_nested+0xf00/0xf00 [ 73.866332][ T8573] ? rcu_read_lock_sched_held+0x3a/0x70 [ 73.872050][ T8573] loop_add+0x9c/0x8c0 [ 73.876119][ T8573] ? find_inode_fast+0x16f/0x220 [ 73.881078][ T8573] loop_probe+0x6a/0x80 [ 73.885269][ T8573] ? loop_add+0x8c0/0x8c0 [ 73.889584][ T8573] blk_request_module+0x111/0x1d0 [ 73.894688][ T8573] blkdev_get_no_open+0x1d5/0x250 [ 73.900057][ T8573] blkdev_get_by_dev.part.0+0x25/0xdd0 [ 73.905589][ T8573] ? devcgroup_check_permission+0x1bb/0x410 [ 73.911757][ T8573] blkdev_open+0x295/0x300 [ 73.917035][ T8573] do_dentry_open+0x4c8/0x11d0 [ 73.921787][ T8573] ? blkdev_get_by_dev+0x80/0x80 [ 73.926721][ T8573] ? __sanitizer_cov_trace_const_cmp4+0x1c/0x70 [ 73.933052][ T8573] ? may_open+0x1f6/0x420 [ 73.937630][ T8573] path_openat+0x1c23/0x27f0 [ 73.942297][ T8573] ? path_lookupat+0x860/0x860 [ 73.947053][ T8573] ? lockdep_hardirqs_on_prepare+0x400/0x400 [ 73.953121][ T8573] do_filp_open+0x1aa/0x400 [ 73.957621][ T8573] ? may_open_dev+0xf0/0xf0 [ 73.962121][ T8573] ? rwlock_bug.part.0+0x90/0x90 [ 73.967159][ T8573] ? __sanitizer_cov_trace_const_cmp8+0x1d/0x70 [ 73.973387][ T8573] ? _find_next_bit+0x1e3/0x260 [ 73.978221][ T8573] ? _raw_spin_unlock+0x24/0x40 [ 73.983056][ T8573] ? alloc_fd+0x2f0/0x670 [ 73.987387][ T8573] do_sys_openat2+0x16d/0x420 [ 73.992061][ T8573] ? build_open_flags+0x6f0/0x6f0 [ 73.997241][ T8573] ? __context_tracking_exit+0xb8/0xe0 [ 74.002702][ T8573] __x64_sys_open+0x119/0x1c0 [ 74.007471][ T8573] ? do_sys_open+0x140/0x140 [ 74.012066][ T8573] ? __secure_computing+0x104/0x360 [ 74.017290][ T8573] do_syscall_64+0x35/0xb0 [ 74.021698][ T8573] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 74.027738][ T8573] RIP: 0033:0x7f405e651840 [ 74.032580][ T8573] 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 [ 74.052271][ T8573] RSP: 002b:00007fff39c1d828 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 [ 74.060892][ T8573] RAX: ffffffffffffffda RBX: 0000563b942d0380 RCX: 00007f405e651840 executing program executing program [ 74.068966][ T8573] RDX: 0000563b93831fe3 RSI: 00000000000a0800 RDI: 0000563b942d1380 [ 74.077280][ T8573] RBP: 00007fff39c1d9a0 R08: 0000563b93831670 R09: 0000000000000010 [ 74.085246][ T8573] R10: 0000563b93831d0c R11: 0000000000000246 R12: 00007fff39c1d8f0 [ 74.093216][ T8573] R13: 0000563b942d17e0 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 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