[ 37.186527][ T26] audit: type=1800 audit(1553570563.064:25): pid=7618 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 37.216079][ T26] audit: type=1800 audit(1553570563.064:26): pid=7618 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 37.244414][ T26] audit: type=1800 audit(1553570563.074:27): pid=7618 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="restorecond" dev="sda1" ino=2436 res=0 [ 37.266335][ T26] audit: type=1800 audit(1553570563.074:28): pid=7618 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. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.10.30' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 49.127584][ T7773] [ 49.129942][ T7773] ====================================================== [ 49.136941][ T7773] WARNING: possible circular locking dependency detected [ 49.143950][ T7773] 5.1.0-rc2-next-20190325 #10 Not tainted [ 49.149636][ T7773] ------------------------------------------------------ [ 49.156629][ T7773] syz-executor866/7773 is trying to acquire lock: [ 49.163012][ T7773] 0000000022338c9e (&p->lock){+.+.}, at: seq_read+0x71/0x1130 [ 49.170471][ T7773] [ 49.170471][ T7773] but task is already holding lock: [ 49.177810][ T7773] 000000002d62b0d1 (&pipe->mutex/1){+.+.}, at: pipe_lock+0x6e/0x80 [ 49.185682][ T7773] [ 49.185682][ T7773] which lock already depends on the new lock. [ 49.185682][ T7773] [ 49.196059][ T7773] [ 49.196059][ T7773] the existing dependency chain (in reverse order) is: [ 49.205048][ T7773] [ 49.205048][ T7773] -> #2 (&pipe->mutex/1){+.+.}: [ 49.212056][ T7773] lock_acquire+0x16f/0x3f0 [ 49.217055][ T7773] __mutex_lock+0xf7/0x1310 [ 49.222055][ T7773] mutex_lock_nested+0x16/0x20 [ 49.227317][ T7773] fifo_open+0x159/0xb00 [ 49.232056][ T7773] do_dentry_open+0x488/0x1160 [ 49.237322][ T7773] vfs_open+0xa0/0xd0 [ 49.241809][ T7773] path_openat+0x10e9/0x46e0 [ 49.246961][ T7773] do_filp_open+0x1a1/0x280 [ 49.251964][ T7773] do_open_execat+0x137/0x690 [ 49.257136][ T7773] __do_execve_file.isra.0+0x178d/0x23f0 [ 49.263267][ T7773] __x64_sys_execve+0x8f/0xc0 [ 49.268440][ T7773] do_syscall_64+0x103/0x610 [ 49.273540][ T7773] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 49.279946][ T7773] [ 49.279946][ T7773] -> #1 (&sig->cred_guard_mutex){+.+.}: [ 49.287663][ T7773] lock_acquire+0x16f/0x3f0 [ 49.292678][ T7773] __mutex_lock+0xf7/0x1310 [ 49.297690][ T7773] mutex_lock_killable_nested+0x16/0x20 [ 49.303757][ T7773] lock_trace+0x4a/0xe0 [ 49.308431][ T7773] proc_pid_syscall+0x98/0x250 [ 49.313703][ T7773] proc_single_show+0xf6/0x170 [ 49.318973][ T7773] seq_read+0x4db/0x1130 [ 49.323733][ T7773] do_iter_read+0x4a9/0x660 [ 49.328744][ T7773] vfs_readv+0xf0/0x160 [ 49.333413][ T7773] default_file_splice_read+0x475/0x890 [ 49.339468][ T7773] do_splice_to+0x12a/0x190 [ 49.344482][ T7773] splice_direct_to_actor+0x2d2/0x970 [ 49.350363][ T7773] do_splice_direct+0x1da/0x2a0 [ 49.355724][ T7773] do_sendfile+0x597/0xd00 [ 49.360652][ T7773] __x64_sys_sendfile64+0x1dd/0x220 [ 49.366363][ T7773] do_syscall_64+0x103/0x610 [ 49.371466][ T7773] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 49.377858][ T7773] [ 49.377858][ T7773] -> #0 (&p->lock){+.+.}: [ 49.384366][ T7773] __lock_acquire+0x239c/0x3fb0 [ 49.389726][ T7773] lock_acquire+0x16f/0x3f0 [ 49.394740][ T7773] __mutex_lock+0xf7/0x1310 [ 49.399765][ T7773] mutex_lock_nested+0x16/0x20 [ 49.405038][ T7773] seq_read+0x71/0x1130 [ 49.409704][ T7773] proc_reg_read+0x1fe/0x2c0 [ 49.414804][ T7773] do_iter_read+0x4a9/0x660 [ 49.419817][ T7773] vfs_readv+0xf0/0x160 [ 49.424487][ T7773] default_file_splice_read+0x475/0x890 [ 49.430542][ T7773] do_splice_to+0x12a/0x190 [ 49.435556][ T7773] do_splice+0x10a9/0x13c0 [ 49.440480][ T7773] __x64_sys_splice+0x2c6/0x330 [ 49.445843][ T7773] do_syscall_64+0x103/0x610 [ 49.450963][ T7773] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 49.457357][ T7773] [ 49.457357][ T7773] other info that might help us debug this: [ 49.457357][ T7773] [ 49.467580][ T7773] Chain exists of: [ 49.467580][ T7773] &p->lock --> &sig->cred_guard_mutex --> &pipe->mutex/1 [ 49.467580][ T7773] [ 49.480514][ T7773] Possible unsafe locking scenario: [ 49.480514][ T7773] [ 49.487954][ T7773] CPU0 CPU1 [ 49.493305][ T7773] ---- ---- [ 49.498655][ T7773] lock(&pipe->mutex/1); [ 49.502975][ T7773] lock(&sig->cred_guard_mutex); [ 49.510500][ T7773] lock(&pipe->mutex/1); [ 49.517336][ T7773] lock(&p->lock); [ 49.521136][ T7773] [ 49.521136][ T7773] *** DEADLOCK *** [ 49.521136][ T7773] [ 49.529277][ T7773] 1 lock held by syz-executor866/7773: [ 49.534718][ T7773] #0: 000000002d62b0d1 (&pipe->mutex/1){+.+.}, at: pipe_lock+0x6e/0x80 [ 49.543053][ T7773] [ 49.543053][ T7773] stack backtrace: [ 49.548936][ T7773] CPU: 0 PID: 7773 Comm: syz-executor866 Not tainted 5.1.0-rc2-next-20190325 #10 [ 49.558027][ T7773] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 49.568071][ T7773] Call Trace: [ 49.571357][ T7773] dump_stack+0x172/0x1f0 [ 49.575681][ T7773] print_circular_bug.isra.0.cold+0x1cc/0x28f [ 49.581743][ T7773] check_prev_add.constprop.0+0xf11/0x23c0 [ 49.587543][ T7773] ? check_usage+0x570/0x570 [ 49.592127][ T7773] ? graph_lock+0x7b/0x200 [ 49.596538][ T7773] ? __lockdep_reset_lock+0x450/0x450 [ 49.601913][ T7773] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 49.608147][ T7773] __lock_acquire+0x239c/0x3fb0 [ 49.613005][ T7773] ? is_bpf_text_address+0xac/0x170 [ 49.618200][ T7773] ? mark_held_locks+0xf0/0xf0 [ 49.622962][ T7773] lock_acquire+0x16f/0x3f0 [ 49.627455][ T7773] ? seq_read+0x71/0x1130 [ 49.631779][ T7773] ? seq_read+0x71/0x1130 [ 49.636115][ T7773] __mutex_lock+0xf7/0x1310 [ 49.640624][ T7773] ? seq_read+0x71/0x1130 [ 49.644944][ T7773] ? seq_read+0x71/0x1130 [ 49.649267][ T7773] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 49.655502][ T7773] ? mutex_trylock+0x1e0/0x1e0 [ 49.660262][ T7773] ? aa_file_perm+0x432/0xeb0 [ 49.664939][ T7773] ? get_page_from_freelist+0x1280/0x4120 [ 49.670654][ T7773] ? aa_path_link+0x460/0x460 [ 49.675325][ T7773] ? seq_dentry+0x2d0/0x2d0 [ 49.679831][ T7773] mutex_lock_nested+0x16/0x20 [ 49.684588][ T7773] ? fsnotify+0x811/0xbc0 [ 49.688916][ T7773] ? mutex_lock_nested+0x16/0x20 [ 49.693852][ T7773] seq_read+0x71/0x1130 [ 49.698039][ T7773] ? seq_dentry+0x2d0/0x2d0 [ 49.702533][ T7773] proc_reg_read+0x1fe/0x2c0 [ 49.707115][ T7773] ? proc_reg_compat_ioctl+0x2a0/0x2a0 [ 49.712565][ T7773] ? rw_verify_area+0x118/0x360 [ 49.717407][ T7773] do_iter_read+0x4a9/0x660 [ 49.721913][ T7773] ? dup_iter+0x260/0x260 [ 49.726238][ T7773] vfs_readv+0xf0/0x160 [ 49.730383][ T7773] ? alloc_pages_current+0x10f/0x210 [ 49.735662][ T7773] ? compat_rw_copy_check_uvector+0x3f0/0x3f0 [ 49.741726][ T7773] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 49.747985][ T7773] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 49.754255][ T7773] ? iov_iter_revert+0xaa0/0xaa0 [ 49.759201][ T7773] ? aa_file_perm+0x40b/0xeb0 [ 49.763870][ T7773] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 49.769593][ T7773] ? iov_iter_pipe+0xba/0x2f0 [ 49.774266][ T7773] default_file_splice_read+0x475/0x890 [ 49.779816][ T7773] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 49.786049][ T7773] ? iter_file_splice_write+0xbe0/0xbe0 [ 49.791589][ T7773] ? lock_acquire+0x16f/0x3f0 [ 49.796259][ T7773] ? pipe_lock+0x6e/0x80 [ 49.800495][ T7773] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 49.806729][ T7773] ? fsnotify+0x811/0xbc0 [ 49.811052][ T7773] ? fsnotify+0xbc0/0xbc0 [ 49.815373][ T7773] ? fsnotify_first_mark+0x210/0x210 [ 49.820650][ T7773] ? find_held_lock+0x35/0x130 [ 49.825411][ T7773] ? security_file_permission+0x94/0x380 [ 49.831042][ T7773] ? rw_verify_area+0x118/0x360 [ 49.835891][ T7773] ? iter_file_splice_write+0xbe0/0xbe0 [ 49.841429][ T7773] do_splice_to+0x12a/0x190 [ 49.845928][ T7773] do_splice+0x10a9/0x13c0 [ 49.850341][ T7773] ? opipe_prep.part.0+0x2d0/0x2d0 [ 49.855443][ T7773] ? __fget_light+0x1a9/0x230 [ 49.860112][ T7773] __x64_sys_splice+0x2c6/0x330 [ 49.864964][ T7773] do_syscall_64+0x103/0x610 [ 49.869561][ T7773] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 49.875445][ T7773] RIP: 0033:0x4459c9 [ 49.879331][ T7773] 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 [ 49.899118][ T7773] RSP: 002b:00007f141f928d88 EFLAGS: 00000246 ORIG_RAX: 0000000000000113 [ 49.907525][ T7773] RAX: ffffffffffffffda RBX: 00000000006dac68 RCX: 00000000004459c9 [ 49.915486][ T7773] RDX: 0000000000000006 RSI: 0000000000000000 RDI: 0000000000000007 [ 49.923458][ T7773] RBP: 00000000006dac60 R08: 0000000000000002 R09: 0000000000000000 [ 49.931421][ T7773] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dac6c [ 49.939384][ T7773] R13: 00000000004ae050 R14: 0000000000000027 R15: 0000000000000872