[ 33.815357][ T26] audit: type=1800 audit(1553570578.734:27): pid=7433 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="restorecond" dev="sda1" ino=2436 res=0 [ 33.839566][ T26] audit: type=1800 audit(1553570578.734:28): pid=7433 uid=0 auid=4294967295 ses=4294967295 subj==unconfined 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. [ 34.539640][ T26] audit: type=1800 audit(1553570579.504:29): pid=7433 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="rc.local" dev="sda1" ino=2432 res=0 [ 34.560781][ T26] audit: type=1800 audit(1553570579.504:30): pid=7433 uid=0 auid=4294967295 ses=4294967295 subj==unconfined 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 '10.128.15.205' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 61.071760][ T7589] [ 61.074397][ T7589] ====================================================== [ 61.081731][ T7589] WARNING: possible circular locking dependency detected [ 61.088885][ T7589] 5.1.0-rc2 #36 Not tainted [ 61.093372][ T7589] ------------------------------------------------------ [ 61.100388][ T7589] syz-executor313/7589 is trying to acquire lock: [ 61.106874][ T7589] 00000000c33e27a0 (&p->lock){+.+.}, at: seq_read+0x71/0x1130 [ 61.114565][ T7589] [ 61.114565][ T7589] but task is already holding lock: [ 61.122413][ T7589] 00000000c9a9488b (&pipe->mutex/1){+.+.}, at: pipe_lock+0x6e/0x80 [ 61.130449][ T7589] [ 61.130449][ T7589] which lock already depends on the new lock. [ 61.130449][ T7589] [ 61.141103][ T7589] [ 61.141103][ T7589] the existing dependency chain (in reverse order) is: [ 61.150435][ T7589] [ 61.150435][ T7589] -> #2 (&pipe->mutex/1){+.+.}: [ 61.157804][ T7589] lock_acquire+0x16f/0x3f0 [ 61.162952][ T7589] __mutex_lock+0xf7/0x1310 [ 61.168073][ T7589] mutex_lock_nested+0x16/0x20 [ 61.173706][ T7589] fifo_open+0x159/0xb00 [ 61.178701][ T7589] do_dentry_open+0x488/0x1160 [ 61.183973][ T7589] vfs_open+0xa0/0xd0 [ 61.188479][ T7589] path_openat+0x10e9/0x46e0 [ 61.193757][ T7589] do_filp_open+0x1a1/0x280 [ 61.198927][ T7589] do_open_execat+0x137/0x690 [ 61.204289][ T7589] __do_execve_file.isra.0+0x178d/0x23f0 [ 61.211434][ T7589] __x64_sys_execve+0x8f/0xc0 [ 61.217249][ T7589] do_syscall_64+0x103/0x610 [ 61.222666][ T7589] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 61.229645][ T7589] [ 61.229645][ T7589] -> #1 (&sig->cred_guard_mutex){+.+.}: [ 61.237495][ T7589] lock_acquire+0x16f/0x3f0 [ 61.242522][ T7589] __mutex_lock+0xf7/0x1310 [ 61.247727][ T7589] mutex_lock_killable_nested+0x16/0x20 [ 61.253949][ T7589] lock_trace+0x4a/0xe0 [ 61.258699][ T7589] proc_pid_syscall+0x98/0x250 [ 61.264310][ T7589] proc_single_show+0xf6/0x170 [ 61.269625][ T7589] seq_read+0x4db/0x1130 [ 61.274631][ T7589] do_iter_read+0x4a9/0x660 [ 61.279687][ T7589] vfs_readv+0xf0/0x160 [ 61.284354][ T7589] default_file_splice_read+0x475/0x890 [ 61.290405][ T7589] do_splice_to+0x12a/0x190 [ 61.295409][ T7589] splice_direct_to_actor+0x2d2/0x970 [ 61.301282][ T7589] do_splice_direct+0x1da/0x2a0 [ 61.306634][ T7589] do_sendfile+0x597/0xd00 [ 61.311639][ T7589] __x64_sys_sendfile64+0x1dd/0x220 [ 61.317531][ T7589] do_syscall_64+0x103/0x610 [ 61.322711][ T7589] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 61.329282][ T7589] [ 61.329282][ T7589] -> #0 (&p->lock){+.+.}: [ 61.335807][ T7589] __lock_acquire+0x239c/0x3fb0 [ 61.341170][ T7589] lock_acquire+0x16f/0x3f0 [ 61.346524][ T7589] __mutex_lock+0xf7/0x1310 [ 61.351530][ T7589] mutex_lock_nested+0x16/0x20 [ 61.356796][ T7589] seq_read+0x71/0x1130 [ 61.361473][ T7589] proc_reg_read+0x1fe/0x2c0 [ 61.366662][ T7589] do_iter_read+0x4a9/0x660 [ 61.371672][ T7589] vfs_readv+0xf0/0x160 [ 61.376611][ T7589] default_file_splice_read+0x475/0x890 [ 61.382659][ T7589] do_splice_to+0x12a/0x190 [ 61.387668][ T7589] do_splice+0x10a9/0x13c0 [ 61.392675][ T7589] __x64_sys_splice+0x2c6/0x330 [ 61.398173][ T7589] do_syscall_64+0x103/0x610 [ 61.403394][ T7589] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 61.409839][ T7589] [ 61.409839][ T7589] other info that might help us debug this: [ 61.409839][ T7589] [ 61.420071][ T7589] Chain exists of: [ 61.420071][ T7589] &p->lock --> &sig->cred_guard_mutex --> &pipe->mutex/1 [ 61.420071][ T7589] [ 61.433340][ T7589] Possible unsafe locking scenario: [ 61.433340][ T7589] [ 61.440861][ T7589] CPU0 CPU1 [ 61.446228][ T7589] ---- ---- [ 61.451601][ T7589] lock(&pipe->mutex/1); [ 61.455927][ T7589] lock(&sig->cred_guard_mutex); [ 61.463736][ T7589] lock(&pipe->mutex/1); [ 61.470575][ T7589] lock(&p->lock); [ 61.474467][ T7589] [ 61.474467][ T7589] *** DEADLOCK *** [ 61.474467][ T7589] [ 61.482705][ T7589] 1 lock held by syz-executor313/7589: [ 61.488141][ T7589] #0: 00000000c9a9488b (&pipe->mutex/1){+.+.}, at: pipe_lock+0x6e/0x80 [ 61.497329][ T7589] [ 61.497329][ T7589] stack backtrace: [ 61.503291][ T7589] CPU: 0 PID: 7589 Comm: syz-executor313 Not tainted 5.1.0-rc2 #36 [ 61.511240][ T7589] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 61.521376][ T7589] Call Trace: [ 61.524966][ T7589] dump_stack+0x172/0x1f0 [ 61.529378][ T7589] print_circular_bug.isra.0.cold+0x1cc/0x28f [ 61.535441][ T7589] check_prev_add.constprop.0+0xf11/0x23c0 [ 61.541233][ T7589] ? check_usage+0x570/0x570 [ 61.545805][ T7589] ? check_prev_add.constprop.0+0x664/0x23c0 [ 61.551766][ T7589] ? graph_lock+0x7b/0x200 [ 61.556249][ T7589] ? __lockdep_reset_lock+0x450/0x450 [ 61.561611][ T7589] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 61.567843][ T7589] __lock_acquire+0x239c/0x3fb0 [ 61.572690][ T7589] ? mark_held_locks+0xf0/0xf0 [ 61.577987][ T7589] lock_acquire+0x16f/0x3f0 [ 61.582495][ T7589] ? seq_read+0x71/0x1130 [ 61.586931][ T7589] ? seq_read+0x71/0x1130 [ 61.591914][ T7589] __mutex_lock+0xf7/0x1310 [ 61.596490][ T7589] ? seq_read+0x71/0x1130 [ 61.600847][ T7589] ? seq_read+0x71/0x1130 [ 61.605303][ T7589] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 61.611525][ T7589] ? mutex_trylock+0x1e0/0x1e0 [ 61.616307][ T7589] ? aa_file_perm+0x432/0xeb0 [ 61.621660][ T7589] ? get_page_from_freelist+0x129c/0x4170 [ 61.627361][ T7589] ? aa_path_link+0x460/0x460 [ 61.632027][ T7589] ? seq_dentry+0x2d0/0x2d0 [ 61.636682][ T7589] mutex_lock_nested+0x16/0x20 [ 61.641423][ T7589] ? fsnotify+0x811/0xbc0 [ 61.645807][ T7589] ? mutex_lock_nested+0x16/0x20 [ 61.650872][ T7589] seq_read+0x71/0x1130 [ 61.655134][ T7589] ? seq_dentry+0x2d0/0x2d0 [ 61.659624][ T7589] proc_reg_read+0x1fe/0x2c0 [ 61.664284][ T7589] ? proc_reg_compat_ioctl+0x2a0/0x2a0 [ 61.669755][ T7589] ? rw_verify_area+0x118/0x360 [ 61.674846][ T7589] do_iter_read+0x4a9/0x660 [ 61.679424][ T7589] ? dup_iter+0x260/0x260 [ 61.683843][ T7589] vfs_readv+0xf0/0x160 [ 61.687980][ T7589] ? alloc_pages_current+0x10f/0x210 [ 61.693246][ T7589] ? compat_rw_copy_check_uvector+0x3f0/0x3f0 [ 61.699300][ T7589] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 61.705523][ T7589] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 61.712364][ T7589] ? iov_iter_revert+0xaa0/0xaa0 [ 61.717280][ T7589] ? aa_file_perm+0x40b/0xeb0 [ 61.722579][ T7589] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 61.728298][ T7589] ? iov_iter_pipe+0xba/0x2f0 [ 61.732956][ T7589] default_file_splice_read+0x475/0x890 [ 61.738488][ T7589] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 61.744797][ T7589] ? iter_file_splice_write+0xbe0/0xbe0 [ 61.750328][ T7589] ? lock_acquire+0x16f/0x3f0 [ 61.755157][ T7589] ? pipe_lock+0x6e/0x80 [ 61.759466][ T7589] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 61.765903][ T7589] ? fsnotify+0x811/0xbc0 [ 61.770386][ T7589] ? fsnotify+0xbc0/0xbc0 [ 61.774704][ T7589] ? fsnotify_first_mark+0x210/0x210 [ 61.779964][ T7589] ? find_held_lock+0x35/0x130 [ 61.784800][ T7589] ? security_file_permission+0x94/0x380 [ 61.790451][ T7589] ? rw_verify_area+0x118/0x360 [ 61.795290][ T7589] ? iter_file_splice_write+0xbe0/0xbe0 [ 61.800819][ T7589] do_splice_to+0x12a/0x190 [ 61.805302][ T7589] do_splice+0x10a9/0x13c0 [ 61.809712][ T7589] ? opipe_prep.part.0+0x2d0/0x2d0 [ 61.814802][ T7589] ? __fget_light+0x1a9/0x230 [ 61.819465][ T7589] __x64_sys_splice+0x2c6/0x330 [ 61.824404][ T7589] do_syscall_64+0x103/0x610 [ 61.828990][ T7589] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 61.835034][ T7589] RIP: 0033:0x4459c9 [ 61.838913][ T7589] 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 [ 61.858682][ T7589] RSP: 002b:00007f5743732d88 EFLAGS: 00000246 ORIG_RAX: 0000000000000113 [ 61.867272][ T7589] RAX: ffffffffffffffda RBX: 00000000006dac68 RCX: 00000000004459c9 [ 61.875220][ T7589] RDX: 0000000000000006 RSI: 0000000000000000 RDI: 0000000000000007 [ 61.883170][ T7589] RBP: 00000000006dac60 R08: 0000000000000002 R09: 0000000000000000 [ 61.891127][ T7589] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dac6c [ 61.899466][ T7589] R13: 00000000004ae050 R14: 0000000000000027 R15: 0000000000000872