[ 48.359069] audit: type=1800 audit(1547200801.127:29): pid=8275 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:kernel_t:s0 op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 48.399023] audit: type=1800 audit(1547200801.127:30): pid=8275 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:kernel_t:s0 op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. Starting mcstransd: [....] Starting file context maintaining daemon: restorecond[?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 '10.128.0.254' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 56.685535] kauditd_printk_skb: 5 callbacks suppressed [ 56.685550] audit: type=1400 audit(1547200809.447:36): avc: denied { map } for pid=8465 comm="syz-executor769" path="/root/syz-executor769094638" dev="sda1" ino=16483 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1 [ 56.692400] [ 56.718831] ====================================================== [ 56.725152] WARNING: possible circular locking dependency detected [ 56.731464] 5.0.0-rc1+ #19 Not tainted [ 56.735326] ------------------------------------------------------ [ 56.741647] syz-executor769/8465 is trying to acquire lock: [ 56.747401] 000000000b2318a4 (&pipe->mutex/1){+.+.}, at: fifo_open+0x159/0xb00 [ 56.754754] [ 56.754754] but task is already holding lock: [ 56.760700] 0000000089b6b1fd (&sig->cred_guard_mutex){+.+.}, at: __do_execve_file.isra.0+0x45d/0x2700 [ 56.770045] [ 56.770045] which lock already depends on the new lock. [ 56.770045] [ 56.778335] [ 56.778335] the existing dependency chain (in reverse order) is: [ 56.785931] [ 56.785931] -> #1 (&sig->cred_guard_mutex){+.+.}: [ 56.792253] __mutex_lock+0x12f/0x1670 [ 56.796642] mutex_lock_interruptible_nested+0x16/0x20 [ 56.802430] proc_pid_attr_write+0x1fa/0x530 [ 56.807337] __vfs_write+0x116/0xb40 [ 56.811552] __kernel_write+0x110/0x3b0 [ 56.816024] write_pipe_buf+0x180/0x240 [ 56.820495] __splice_from_pipe+0x39a/0x7e0 [ 56.825312] splice_from_pipe+0x1ea/0x310 [ 56.829963] default_file_splice_write+0x3c/0x90 [ 56.835232] do_splice+0x64b/0x1410 [ 56.839356] __x64_sys_splice+0x2c6/0x330 [ 56.844017] do_syscall_64+0x1a3/0x800 [ 56.848407] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 56.854106] [ 56.854106] -> #0 (&pipe->mutex/1){+.+.}: [ 56.859836] lock_acquire+0x1db/0x570 [ 56.864141] __mutex_lock+0x12f/0x1670 [ 56.868546] mutex_lock_nested+0x16/0x20 [ 56.873111] fifo_open+0x159/0xb00 [ 56.877148] do_dentry_open+0x48a/0x1210 [ 56.881709] vfs_open+0xa0/0xd0 [ 56.885488] path_openat+0x144f/0x5650 [ 56.889876] do_filp_open+0x26f/0x370 [ 56.894175] do_open_execat+0x20e/0x930 [ 56.898676] __do_execve_file.isra.0+0x1966/0x2700 [ 56.904121] __x64_sys_execve+0x8f/0xc0 [ 56.908614] do_syscall_64+0x1a3/0x800 [ 56.913019] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 56.918703] [ 56.918703] other info that might help us debug this: [ 56.918703] [ 56.926819] Possible unsafe locking scenario: [ 56.926819] [ 56.932850] CPU0 CPU1 [ 56.937490] ---- ---- [ 56.942146] lock(&sig->cred_guard_mutex); [ 56.946492] lock(&pipe->mutex/1); [ 56.952632] lock(&sig->cred_guard_mutex); [ 56.959448] lock(&pipe->mutex/1); [ 56.963054] [ 56.963054] *** DEADLOCK *** [ 56.963054] [ 56.969092] 1 lock held by syz-executor769/8465: [ 56.973839] #0: 0000000089b6b1fd (&sig->cred_guard_mutex){+.+.}, at: __do_execve_file.isra.0+0x45d/0x2700 [ 56.983622] [ 56.983622] stack backtrace: [ 56.988118] CPU: 0 PID: 8465 Comm: syz-executor769 Not tainted 5.0.0-rc1+ #19 [ 56.995381] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 57.004737] Call Trace: [ 57.007320] dump_stack+0x1db/0x2d0 [ 57.010943] ? dump_stack_print_info.cold+0x20/0x20 [ 57.015967] ? print_stack_trace+0x77/0xb0 [ 57.020184] ? vprintk_func+0x86/0x189 [ 57.024055] print_circular_bug.isra.0.cold+0x1cc/0x28f [ 57.029415] __lock_acquire+0x3014/0x4a30 [ 57.033555] ? is_bpf_text_address+0xac/0x170 [ 57.038031] ? mark_held_locks+0x100/0x100 [ 57.042260] ? mark_held_locks+0xb1/0x100 [ 57.046388] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 57.051468] ? lockdep_hardirqs_on+0x415/0x5d0 [ 57.056031] ? trace_hardirqs_off_caller+0x300/0x300 [ 57.061117] ? do_raw_spin_trylock+0x270/0x270 [ 57.065677] ? add_lock_to_list.isra.0+0x450/0x450 [ 57.070589] ? print_usage_bug+0xd0/0xd0 [ 57.074628] ? __lock_is_held+0xb6/0x140 [ 57.078669] lock_acquire+0x1db/0x570 [ 57.082463] ? fifo_open+0x159/0xb00 [ 57.086158] ? ___might_sleep+0x1e7/0x310 [ 57.090285] ? lock_release+0xc40/0xc40 [ 57.094237] ? fifo_open+0x159/0xb00 [ 57.097929] ? fifo_open+0x159/0xb00 [ 57.101620] __mutex_lock+0x12f/0x1670 [ 57.105495] ? fifo_open+0x159/0xb00 [ 57.109190] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 57.114706] ? fifo_open+0x159/0xb00 [ 57.118415] ? check_preemption_disabled+0x48/0x290 [ 57.123427] ? lockdep_init_map+0x10c/0x5b0 [ 57.127740] ? mutex_trylock+0x2d0/0x2d0 [ 57.131821] ? add_lock_to_list.isra.0+0x450/0x450 [ 57.136746] ? __mutex_init+0x1f6/0x2a0 [ 57.140703] ? psi_task_change.cold+0x1ec/0x1ec [ 57.145352] ? fifo_open+0x2b5/0xb00 [ 57.149063] ? find_held_lock+0x35/0x120 [ 57.153105] ? fifo_open+0x2b5/0xb00 [ 57.156823] ? lock_acquire+0x1db/0x570 [ 57.160784] ? kasan_check_read+0x11/0x20 [ 57.164946] ? do_raw_spin_unlock+0xa0/0x330 [ 57.169354] ? do_raw_spin_trylock+0x270/0x270 [ 57.173922] mutex_lock_nested+0x16/0x20 [ 57.177964] ? _raw_spin_unlock+0x2d/0x50 [ 57.182093] ? mutex_lock_nested+0x16/0x20 [ 57.186308] fifo_open+0x159/0xb00 [ 57.189861] do_dentry_open+0x48a/0x1210 [ 57.193906] ? pipe_release+0x280/0x280 [ 57.197860] ? chown_common+0x740/0x740 [ 57.201826] ? security_inode_permission+0xd5/0x110 [ 57.206844] ? inode_permission+0xb4/0x570 [ 57.211167] vfs_open+0xa0/0xd0 [ 57.214430] path_openat+0x144f/0x5650 [ 57.218298] ? __save_stack_trace+0x8a/0xf0 [ 57.222619] ? path_lookupat.isra.0+0xba0/0xba0 [ 57.227265] ? selinux_cred_prepare+0x49/0xb0 [ 57.231738] ? security_prepare_creds+0x7d/0xc0 [ 57.236403] ? prepare_creds+0x3c4/0x4e0 [ 57.240461] ? __do_execve_file.isra.0+0x47a/0x2700 [ 57.245472] ? __x64_sys_execve+0x8f/0xc0 [ 57.249604] ? do_syscall_64+0x1a3/0x800 [ 57.253660] ? __lock_acquire+0x572/0x4a30 [ 57.257876] ? __lock_is_held+0xb6/0x140 [ 57.261920] do_filp_open+0x26f/0x370 [ 57.265697] ? may_open_dev+0x100/0x100 [ 57.269657] ? add_lock_to_list.isra.0+0x450/0x450 [ 57.274564] ? add_lock_to_list.isra.0+0x450/0x450 [ 57.279512] ? __do_execve_file.isra.0+0x901/0x2700 [ 57.284513] do_open_execat+0x20e/0x930 [ 57.288470] ? unregister_binfmt+0x2b0/0x2b0 [ 57.292862] ? kasan_check_read+0x11/0x20 [ 57.296990] ? do_raw_spin_trylock+0x270/0x270 [ 57.301557] ? __phys_addr_symbol+0x30/0x70 [ 57.305876] __do_execve_file.isra.0+0x1966/0x2700 [ 57.310788] ? rcu_pm_notify+0xd0/0xd0 [ 57.314663] ? copy_strings_kernel+0x110/0x110 [ 57.319226] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 57.324744] ? strncpy_from_user+0x3aa/0x4e0 [ 57.329190] ? digsig_verify.cold+0x32/0x32 [ 57.333490] ? kmem_cache_alloc+0x341/0x710 [ 57.337792] ? do_syscall_64+0x8c/0x800 [ 57.341773] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 57.347295] ? getname_flags+0x277/0x5b0 [ 57.351352] ? trace_hardirqs_off_caller+0x300/0x300 [ 57.356464] __x64_sys_execve+0x8f/0xc0 [ 57.360452] do_syscall_64+0x1a3/0x800 [ 57.364322] ? syscall_return_slowpath+0x5f0/0x5f0 [ 57.369247] ? prepare_exit_to_usermode+0x232/0x3b0 [ 57.374252] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 57.379109] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 57.384291] RIP: 0033:0x440139 [ 57.387490] Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 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 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00 [ 57.406371] RSP: 002b:00007ffefe458248 EFLAGS: 00000217 ORIG_RAX: 000000000000003b [ 57.414057] RAX: ffffffffffffffda RBX: 0030656c69662f2e RCX: 0000000000440139 [ 57.421311] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000240 [ 57.428562] RBP: 00000000006ca018 R08: 0000000000000000 R09: 0000000000000000 [ 57.435815] R10: 0000000000000000 R11: 0000000000000217 R12: 00000000004019c0 [ 57.443065] R13: 0000000000401a50 R14: 0000000000000000 R15: 0000000000000000