[ 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 '10.128.1.92' (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 syzkaller login: [ 68.287736][ T8538] [ 68.290094][ T8538] ====================================================== [ 68.297105][ T8538] WARNING: possible circular locking dependency detected [ 68.304099][ T8538] 5.14.0-rc4-syzkaller #0 Not tainted [ 68.309446][ T8538] ------------------------------------------------------ [ 68.316437][ T8538] systemd-udevd/8538 is trying to acquire lock: [ 68.322682][ T8538] ffffffff8c487928 (loop_ctl_mutex){+.+.}-{3:3}, at: loop_add+0x9c/0x8c0 [ 68.331109][ T8538] [ 68.331109][ T8538] but task is already holding lock: [ 68.338447][ T8538] ffffffff8c1f3ec8 (major_names_lock){+.+.}-{3:3}, at: blk_request_module+0x25/0x1d0 [ 68.347902][ T8538] [ 68.347902][ T8538] which lock already depends on the new lock. [ 68.347902][ T8538] [ 68.358277][ T8538] [ 68.358277][ T8538] the existing dependency chain (in reverse order) is: [ 68.367267][ T8538] [ 68.367267][ T8538] -> #3 (major_names_lock){+.+.}-{3:3}: [ 68.374966][ T8538] __mutex_lock+0x12a/0x10a0 [ 68.380068][ T8538] __register_blkdev+0x2b/0x3e0 [ 68.385419][ T8538] register_mtd_blktrans+0x85/0x3c0 [ 68.391118][ T8538] do_one_initcall+0x103/0x650 [ 68.396388][ T8538] kernel_init_freeable+0x6b8/0x741 [ 68.402100][ T8538] kernel_init+0x1a/0x1d0 [ 68.406929][ T8538] ret_from_fork+0x1f/0x30 [ 68.411846][ T8538] [ 68.411846][ T8538] -> #2 (mtd_table_mutex){+.+.}-{3:3}: [ 68.419486][ T8538] __mutex_lock+0x12a/0x10a0 [ 68.424578][ T8538] blktrans_open+0x69/0x600 [ 68.429580][ T8538] blkdev_get_whole+0xa1/0x420 [ 68.434854][ T8538] blkdev_get_by_dev.part.0+0x30c/0xdd0 [ 68.440906][ T8538] blkdev_open+0x295/0x300 [ 68.445820][ T8538] do_dentry_open+0x4c8/0x11d0 [ 68.451084][ T8538] path_openat+0x1c23/0x27f0 [ 68.456179][ T8538] do_filp_open+0x1aa/0x400 [ 68.461182][ T8538] do_sys_openat2+0x16d/0x420 [ 68.466358][ T8538] __x64_sys_open+0x119/0x1c0 [ 68.471539][ T8538] do_syscall_64+0x35/0xb0 [ 68.476460][ T8538] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 68.482855][ T8538] [ 68.482855][ T8538] -> #1 (&disk->open_mutex){+.+.}-{3:3}: [ 68.490644][ T8538] __mutex_lock+0x12a/0x10a0 [ 68.495733][ T8538] del_gendisk+0x8b/0x770 [ 68.500562][ T8538] loop_control_ioctl+0x3b5/0x450 [ 68.506086][ T8538] __x64_sys_ioctl+0x193/0x200 [ 68.511367][ T8538] do_syscall_64+0x35/0xb0 [ 68.516289][ T8538] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 68.522681][ T8538] [ 68.522681][ T8538] -> #0 (loop_ctl_mutex){+.+.}-{3:3}: [ 68.530210][ T8538] __lock_acquire+0x2a07/0x54a0 [ 68.535562][ T8538] lock_acquire+0x1ab/0x510 [ 68.540566][ T8538] __mutex_lock+0x12a/0x10a0 [ 68.545659][ T8538] loop_add+0x9c/0x8c0 [ 68.550226][ T8538] loop_probe+0x6a/0x80 [ 68.554893][ T8538] blk_request_module+0x111/0x1d0 [ 68.560424][ T8538] blkdev_get_no_open+0x1d5/0x250 [ 68.566035][ T8538] blkdev_get_by_dev.part.0+0x25/0xdd0 [ 68.571991][ T8538] blkdev_open+0x295/0x300 [ 68.576907][ T8538] do_dentry_open+0x4c8/0x11d0 [ 68.582170][ T8538] path_openat+0x1c23/0x27f0 [ 68.587375][ T8538] do_filp_open+0x1aa/0x400 [ 68.592383][ T8538] do_sys_openat2+0x16d/0x420 [ 68.597561][ T8538] __x64_sys_open+0x119/0x1c0 [ 68.602736][ T8538] do_syscall_64+0x35/0xb0 [ 68.607667][ T8538] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 68.614063][ T8538] [ 68.614063][ T8538] other info that might help us debug this: [ 68.614063][ T8538] [ 68.624266][ T8538] Chain exists of: [ 68.624266][ T8538] loop_ctl_mutex --> mtd_table_mutex --> major_names_lock [ 68.624266][ T8538] [ 68.637275][ T8538] Possible unsafe locking scenario: [ 68.637275][ T8538] [ 68.644706][ T8538] CPU0 CPU1 [ 68.650049][ T8538] ---- ---- [ 68.655404][ T8538] lock(major_names_lock); [ 68.659894][ T8538] lock(mtd_table_mutex); [ 68.666850][ T8538] lock(major_names_lock); [ 68.673851][ T8538] lock(loop_ctl_mutex); [ 68.678160][ T8538] [ 68.678160][ T8538] *** DEADLOCK *** [ 68.678160][ T8538] [ 68.686284][ T8538] 1 lock held by systemd-udevd/8538: [ 68.691558][ T8538] #0: ffffffff8c1f3ec8 (major_names_lock){+.+.}-{3:3}, at: blk_request_module+0x25/0x1d0 [ 68.701463][ T8538] [ 68.701463][ T8538] stack backtrace: [ 68.707327][ T8538] CPU: 0 PID: 8538 Comm: systemd-udevd Not tainted 5.14.0-rc4-syzkaller #0 [ 68.715900][ T8538] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 68.725936][ T8538] Call Trace: [ 68.729219][ T8538] dump_stack_lvl+0xcd/0x134 [ 68.733801][ T8538] check_noncircular+0x25f/0x2e0 [ 68.738723][ T8538] ? lockdep_hardirqs_on_prepare+0x400/0x400 [ 68.744687][ T8538] ? print_circular_bug+0x1e0/0x1e0 [ 68.749879][ T8538] ? lock_chain_count+0x20/0x20 [ 68.754718][ T8538] ? lockdep_lock+0xc6/0x200 [ 68.759302][ T8538] ? call_rcu_zapped+0xb0/0xb0 [ 68.764053][ T8538] __lock_acquire+0x2a07/0x54a0 [ 68.768883][ T8538] ? lockdep_hardirqs_on_prepare+0x400/0x400 [ 68.774842][ T8538] lock_acquire+0x1ab/0x510 [ 68.779325][ T8538] ? loop_add+0x9c/0x8c0 [ 68.783551][ T8538] ? lock_release+0x720/0x720 [ 68.788205][ T8538] ? path_openat+0x1c23/0x27f0 [ 68.792963][ T8538] ? do_filp_open+0x1aa/0x400 [ 68.797620][ T8538] ? do_sys_openat2+0x16d/0x420 [ 68.802450][ T8538] ? __x64_sys_open+0x119/0x1c0 [ 68.807297][ T8538] __mutex_lock+0x12a/0x10a0 [ 68.811888][ T8538] ? loop_add+0x9c/0x8c0 [ 68.816110][ T8538] ? loop_add+0x9c/0x8c0 [ 68.820340][ T8538] ? mark_held_locks+0x9f/0xe0 [ 68.825091][ T8538] ? mutex_lock_io_nested+0xf00/0xf00 [ 68.830449][ T8538] ? rcu_read_lock_sched_held+0x3a/0x70 [ 68.835976][ T8538] loop_add+0x9c/0x8c0 [ 68.840023][ T8538] ? find_inode_fast+0x16f/0x220 [ 68.844941][ T8538] loop_probe+0x6a/0x80 [ 68.849089][ T8538] ? loop_add+0x8c0/0x8c0 [ 68.853395][ T8538] blk_request_module+0x111/0x1d0 [ 68.858402][ T8538] blkdev_get_no_open+0x1d5/0x250 [ 68.863407][ T8538] blkdev_get_by_dev.part.0+0x25/0xdd0 [ 68.868866][ T8538] ? devcgroup_check_permission+0x1bb/0x410 [ 68.874749][ T8538] blkdev_open+0x295/0x300 [ 68.879149][ T8538] do_dentry_open+0x4c8/0x11d0 [ 68.883893][ T8538] ? blkdev_get_by_dev+0x80/0x80 [ 68.888807][ T8538] ? __sanitizer_cov_trace_const_cmp4+0x1c/0x70 [ 68.895212][ T8538] ? may_open+0x1f6/0x420 [ 68.899520][ T8538] path_openat+0x1c23/0x27f0 [ 68.904089][ T8538] ? path_lookupat+0x860/0x860 [ 68.908833][ T8538] ? lockdep_hardirqs_on_prepare+0x400/0x400 [ 68.914794][ T8538] do_filp_open+0x1aa/0x400 [ 68.919277][ T8538] ? may_open_dev+0xf0/0xf0 [ 68.923777][ T8538] ? rwlock_bug.part.0+0x90/0x90 [ 68.928715][ T8538] ? __sanitizer_cov_trace_const_cmp8+0x1d/0x70 [ 68.934935][ T8538] ? _find_next_bit+0x1e3/0x260 [ 68.939768][ T8538] ? _raw_spin_unlock+0x24/0x40 [ 68.944597][ T8538] ? alloc_fd+0x2f0/0x670 [ 68.948909][ T8538] do_sys_openat2+0x16d/0x420 [ 68.953570][ T8538] ? build_open_flags+0x6f0/0x6f0 [ 68.958578][ T8538] ? __context_tracking_exit+0xb8/0xe0 [ 68.964365][ T8538] __x64_sys_open+0x119/0x1c0 [ 68.969421][ T8538] ? do_sys_open+0x140/0x140 [ 68.973997][ T8538] ? __secure_computing+0x104/0x360 [ 68.979189][ T8538] do_syscall_64+0x35/0xb0 [ 68.983633][ T8538] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 68.989514][ T8538] RIP: 0033:0x7f3c01027840 [ 68.993911][ T8538] 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 [ 69.013496][ T8538] RSP: 002b:00007ffd23cfe978 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 [ 69.021914][ T8538] RAX: ffffffffffffffda RBX: 000055e1adbe3ee0 RCX: 00007f3c01027840 [ 69.029882][ T8538] RDX: 000055e1ad988fe3 RSI: 00000000000a0800 RDI: 000055e1adbf7970 executing program executing program [ 69.037834][ T8538] RBP: 00007ffd23cfeaf0 R08: 000055e1ad988670 R09: 0000000000000010 [ 69.045783][ T8538] R10: 000055e1ad988d0c R11: 0000000000000246 R12: 00007ffd23cfea40 [ 69.053732][ T8538] R13: 000055e1adbf7520 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