[ 35.997008][ T26] audit: type=1800 audit(1553570591.893:27): pid=7524 uid=0 auid=4294967295 ses=4294967295 subj=_ op=collect_data cause=failed(directio) comm="startpar" name="restorecond" dev="sda1" ino=2436 res=0 [ 36.017166][ T26] audit: type=1800 audit(1553570591.893:28): pid=7524 uid=0 auid=4294967295 ses=4294967295 subj=_ op=collect_data cause=failed(directio) comm="startpar" name="ssh" dev="sda1" ino=2417 res=0 [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. [ 36.598681][ T26] audit: type=1800 audit(1553570592.573:29): pid=7524 uid=0 auid=4294967295 ses=4294967295 subj=_ op=collect_data cause=failed(directio) comm="startpar" name="rc.local" dev="sda1" ino=2432 res=0 [ 36.628968][ T26] audit: type=1800 audit(1553570592.573:30): pid=7524 uid=0 auid=4294967295 ses=4294967295 subj=_ op=collect_data cause=failed(directio) comm="startpar" name="rmnologin" dev="sda1" ino=2423 res=0 Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.0.199' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 51.069324][ T7682] [ 51.071676][ T7682] ====================================================== [ 51.078696][ T7682] WARNING: possible circular locking dependency detected [ 51.085688][ T7682] 5.1.0-rc2 #36 Not tainted [ 51.090163][ T7682] ------------------------------------------------------ [ 51.097153][ T7682] syz-executor222/7682 is trying to acquire lock: [ 51.103533][ T7682] 00000000a6dcec64 (&p->lock){+.+.}, at: seq_read+0x71/0x1130 [ 51.110969][ T7682] [ 51.110969][ T7682] but task is already holding lock: [ 51.118307][ T7682] 00000000e3906fe3 (&pipe->mutex/1){+.+.}, at: pipe_lock+0x6e/0x80 [ 51.126182][ T7682] [ 51.126182][ T7682] which lock already depends on the new lock. [ 51.126182][ T7682] [ 51.136557][ T7682] [ 51.136557][ T7682] the existing dependency chain (in reverse order) is: [ 51.145540][ T7682] [ 51.145540][ T7682] -> #2 (&pipe->mutex/1){+.+.}: [ 51.152544][ T7682] lock_acquire+0x16f/0x3f0 [ 51.157544][ T7682] __mutex_lock+0xf7/0x1310 [ 51.162541][ T7682] mutex_lock_nested+0x16/0x20 [ 51.167801][ T7682] fifo_open+0x159/0xb00 [ 51.172537][ T7682] do_dentry_open+0x488/0x1160 [ 51.177793][ T7682] vfs_open+0xa0/0xd0 [ 51.182272][ T7682] path_openat+0x10e9/0x46e0 [ 51.187356][ T7682] do_filp_open+0x1a1/0x280 [ 51.192353][ T7682] do_open_execat+0x137/0x690 [ 51.197526][ T7682] __do_execve_file.isra.0+0x178d/0x23f0 [ 51.203654][ T7682] __x64_sys_execve+0x8f/0xc0 [ 51.208832][ T7682] do_syscall_64+0x103/0x610 [ 51.213939][ T7682] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 51.220319][ T7682] [ 51.220319][ T7682] -> #1 (&sig->cred_guard_mutex){+.+.}: [ 51.228027][ T7682] lock_acquire+0x16f/0x3f0 [ 51.233043][ T7682] __mutex_lock+0xf7/0x1310 [ 51.238059][ T7682] mutex_lock_killable_nested+0x16/0x20 [ 51.244115][ T7682] lock_trace+0x4a/0xe0 [ 51.248778][ T7682] proc_pid_syscall+0x98/0x250 [ 51.254051][ T7682] proc_single_show+0xf6/0x170 [ 51.259325][ T7682] seq_read+0x4db/0x1130 [ 51.264079][ T7682] do_iter_read+0x4a9/0x660 [ 51.269106][ T7682] vfs_readv+0xf0/0x160 [ 51.273770][ T7682] default_file_splice_read+0x475/0x890 [ 51.279829][ T7682] do_splice_to+0x12a/0x190 [ 51.284859][ T7682] splice_direct_to_actor+0x2d2/0x970 [ 51.290760][ T7682] do_splice_direct+0x1da/0x2a0 [ 51.296130][ T7682] do_sendfile+0x597/0xd00 [ 51.301056][ T7682] __x64_sys_sendfile64+0x1dd/0x220 [ 51.306766][ T7682] do_syscall_64+0x103/0x610 [ 51.311873][ T7682] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 51.318264][ T7682] [ 51.318264][ T7682] -> #0 (&p->lock){+.+.}: [ 51.324761][ T7682] __lock_acquire+0x239c/0x3fb0 [ 51.330128][ T7682] lock_acquire+0x16f/0x3f0 [ 51.335144][ T7682] __mutex_lock+0xf7/0x1310 [ 51.340155][ T7682] mutex_lock_nested+0x16/0x20 [ 51.345429][ T7682] seq_read+0x71/0x1130 [ 51.350103][ T7682] proc_reg_read+0x1fe/0x2c0 [ 51.355206][ T7682] do_iter_read+0x4a9/0x660 [ 51.360217][ T7682] vfs_readv+0xf0/0x160 [ 51.364885][ T7682] default_file_splice_read+0x475/0x890 [ 51.370939][ T7682] do_splice_to+0x12a/0x190 [ 51.375964][ T7682] do_splice+0x10a9/0x13c0 [ 51.380986][ T7682] __x64_sys_splice+0x2c6/0x330 [ 51.386448][ T7682] do_syscall_64+0x103/0x610 [ 51.391550][ T7682] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 51.397943][ T7682] [ 51.397943][ T7682] other info that might help us debug this: [ 51.397943][ T7682] [ 51.408173][ T7682] Chain exists of: [ 51.408173][ T7682] &p->lock --> &sig->cred_guard_mutex --> &pipe->mutex/1 [ 51.408173][ T7682] [ 51.421093][ T7682] Possible unsafe locking scenario: [ 51.421093][ T7682] [ 51.428535][ T7682] CPU0 CPU1 [ 51.433886][ T7682] ---- ---- [ 51.439396][ T7682] lock(&pipe->mutex/1); [ 51.443714][ T7682] lock(&sig->cred_guard_mutex); [ 51.451238][ T7682] lock(&pipe->mutex/1); [ 51.458074][ T7682] lock(&p->lock); [ 51.461874][ T7682] [ 51.461874][ T7682] *** DEADLOCK *** [ 51.461874][ T7682] [ 51.470008][ T7682] 1 lock held by syz-executor222/7682: [ 51.475445][ T7682] #0: 00000000e3906fe3 (&pipe->mutex/1){+.+.}, at: pipe_lock+0x6e/0x80 [ 51.483778][ T7682] [ 51.483778][ T7682] stack backtrace: [ 51.489660][ T7682] CPU: 0 PID: 7682 Comm: syz-executor222 Not tainted 5.1.0-rc2 #36 [ 51.497528][ T7682] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 51.507565][ T7682] Call Trace: [ 51.510856][ T7682] dump_stack+0x172/0x1f0 [ 51.515205][ T7682] print_circular_bug.isra.0.cold+0x1cc/0x28f [ 51.521263][ T7682] check_prev_add.constprop.0+0xf11/0x23c0 [ 51.527057][ T7682] ? check_usage+0x570/0x570 [ 51.531641][ T7682] ? check_prev_add.constprop.0+0x664/0x23c0 [ 51.537610][ T7682] ? graph_lock+0x7b/0x200 [ 51.542019][ T7682] ? __lockdep_reset_lock+0x450/0x450 [ 51.547382][ T7682] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 51.553612][ T7682] __lock_acquire+0x239c/0x3fb0 [ 51.558456][ T7682] ? mark_held_locks+0xf0/0xf0 [ 51.563212][ T7682] lock_acquire+0x16f/0x3f0 [ 51.567706][ T7682] ? seq_read+0x71/0x1130 [ 51.572288][ T7682] ? seq_read+0x71/0x1130 [ 51.576611][ T7682] __mutex_lock+0xf7/0x1310 [ 51.581117][ T7682] ? seq_read+0x71/0x1130 [ 51.585439][ T7682] ? find_held_lock+0x35/0x130 [ 51.590193][ T7682] ? seq_read+0x71/0x1130 [ 51.594515][ T7682] ? kernel_poison_pages+0x178/0x2b0 [ 51.599789][ T7682] ? mutex_trylock+0x1e0/0x1e0 [ 51.604542][ T7682] ? prep_new_page+0x122/0x300 [ 51.609297][ T7682] ? trace_hardirqs_on+0x67/0x230 [ 51.614310][ T7682] ? __inc_numa_state+0x49/0xe0 [ 51.619152][ T7682] ? get_page_from_freelist+0x129c/0x4170 [ 51.624950][ T7682] ? seq_dentry+0x2d0/0x2d0 [ 51.629448][ T7682] mutex_lock_nested+0x16/0x20 [ 51.634203][ T7682] ? fsnotify+0x811/0xbc0 [ 51.638519][ T7682] ? mutex_lock_nested+0x16/0x20 [ 51.643444][ T7682] seq_read+0x71/0x1130 [ 51.647597][ T7682] ? seq_dentry+0x2d0/0x2d0 [ 51.652087][ T7682] proc_reg_read+0x1fe/0x2c0 [ 51.656678][ T7682] ? proc_reg_compat_ioctl+0x2a0/0x2a0 [ 51.662131][ T7682] ? rw_verify_area+0x118/0x360 [ 51.666976][ T7682] do_iter_read+0x4a9/0x660 [ 51.671740][ T7682] ? dup_iter+0x260/0x260 [ 51.676061][ T7682] vfs_readv+0xf0/0x160 [ 51.680202][ T7682] ? alloc_pages_current+0x10f/0x210 [ 51.685481][ T7682] ? compat_rw_copy_check_uvector+0x3f0/0x3f0 [ 51.691550][ T7682] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 51.697784][ T7682] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 51.704270][ T7682] ? iov_iter_revert+0xaa0/0xaa0 [ 51.709197][ T7682] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 51.714903][ T7682] ? iov_iter_pipe+0xba/0x2f0 [ 51.719574][ T7682] default_file_splice_read+0x475/0x890 [ 51.725118][ T7682] ? iter_file_splice_write+0xbe0/0xbe0 [ 51.730667][ T7682] ? lock_acquire+0x16f/0x3f0 [ 51.735331][ T7682] ? pipe_lock+0x6e/0x80 [ 51.739562][ T7682] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 51.745793][ T7682] ? fsnotify+0x811/0xbc0 [ 51.750118][ T7682] ? fsnotify+0xbc0/0xbc0 [ 51.754441][ T7682] ? fsnotify_first_mark+0x210/0x210 [ 51.759715][ T7682] ? find_held_lock+0x35/0x130 [ 51.764467][ T7682] ? __fget+0x35a/0x550 [ 51.768615][ T7682] ? security_file_permission+0x94/0x380 [ 51.774247][ T7682] ? rw_verify_area+0x118/0x360 [ 51.779086][ T7682] ? iter_file_splice_write+0xbe0/0xbe0 [ 51.784627][ T7682] do_splice_to+0x12a/0x190 [ 51.789122][ T7682] do_splice+0x10a9/0x13c0 [ 51.793530][ T7682] ? opipe_prep.part.0+0x2d0/0x2d0 [ 51.798628][ T7682] ? __fget_light+0x1a9/0x230 [ 51.803297][ T7682] __x64_sys_splice+0x2c6/0x330 [ 51.808142][ T7682] do_syscall_64+0x103/0x610 [ 51.812722][ T7682] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 51.818600][ T7682] RIP: 0033:0x4459c9 [ 51.822483][ T7682] Code: e8 3c ba 02 00 48 83 c4 18 c3 0f 1f 80 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 0f 83 8b 12 fc ff c3 66 2e 0f 1f 84 00 00 00 00 [ 51.842076][ T7682] RSP: 002b:00007fb132cd3d88 EFLAGS: 00000246 ORIG_RAX: 0000000000000113 [ 51.850478][ T7682] RAX: ffffffffffffffda RBX: 00000000006dac68 RCX: 00000000004459c9 [ 51.858433][ T7682] RDX: 0000000000000006 RSI: 0000000000000000 RDI: 0000000000000007 [ 51.866390][ T7682] RBP: 00000000006dac60 R08: 0000000000000002 R09: 0000000000000000 [ 51.874349][ T7682] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dac6c [ 51.882305][ T7682] R13: 00000000004ae050 R14: 0000000000000027 R15: 0000000000000872