[ 41.267051][ T26] audit: type=1800 audit(1547205551.595:25): pid=7951 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 41.295665][ T26] audit: type=1800 audit(1547205551.595:26): pid=7951 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 41.333235][ T26] audit: type=1800 audit(1547205551.605:27): pid=7951 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="restorecond" dev="sda1" ino=2436 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. [....] startpar: service(s) returned failure: rsyslog ...[?25l[?1c7[FAIL8[?25h[?0c failed! Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.0.56' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 50.672425][ T8125] [ 50.674774][ T8125] ====================================================== [ 50.681772][ T8125] WARNING: possible circular locking dependency detected [ 50.688774][ T8125] 5.0.0-rc1-next-20190111 #10 Not tainted [ 50.694460][ T8125] ------------------------------------------------------ [ 50.701446][ T8125] syz-executor231/8125 is trying to acquire lock: [ 50.707824][ T8125] 00000000361b40e0 (&pipe->mutex/1){+.+.}, at: fifo_open+0x159/0xb00 [ 50.715870][ T8125] [ 50.715870][ T8125] but task is already holding lock: [ 50.723208][ T8125] 00000000b00d0264 (&sig->cred_guard_mutex){+.+.}, at: __do_execve_file.isra.0+0x45d/0x2700 [ 50.733249][ T8125] [ 50.733249][ T8125] which lock already depends on the new lock. [ 50.733249][ T8125] [ 50.743641][ T8125] [ 50.743641][ T8125] the existing dependency chain (in reverse order) is: [ 50.752640][ T8125] [ 50.752640][ T8125] -> #1 (&sig->cred_guard_mutex){+.+.}: [ 50.760337][ T8125] __mutex_lock+0x12f/0x1670 [ 50.765426][ T8125] mutex_lock_interruptible_nested+0x16/0x20 [ 50.771898][ T8125] proc_pid_attr_write+0x200/0x580 [ 50.777502][ T8125] __vfs_write+0x116/0xb40 [ 50.782428][ T8125] __kernel_write+0x110/0x3b0 [ 50.787610][ T8125] write_pipe_buf+0x180/0x240 [ 50.792775][ T8125] __splice_from_pipe+0x39a/0x7e0 [ 50.798307][ T8125] splice_from_pipe+0x1ea/0x310 [ 50.803661][ T8125] default_file_splice_write+0x3c/0x90 [ 50.809624][ T8125] do_splice+0x64b/0x1410 [ 50.814447][ T8125] __x64_sys_splice+0x2c6/0x330 [ 50.819792][ T8125] do_syscall_64+0x1a3/0x800 [ 50.824875][ T8125] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 50.831285][ T8125] [ 50.831285][ T8125] -> #0 (&pipe->mutex/1){+.+.}: [ 50.838300][ T8125] lock_acquire+0x1db/0x570 [ 50.843300][ T8125] __mutex_lock+0x12f/0x1670 [ 50.848396][ T8125] mutex_lock_nested+0x16/0x20 [ 50.853681][ T8125] fifo_open+0x159/0xb00 [ 50.858426][ T8125] do_dentry_open+0x495/0x1230 [ 50.863698][ T8125] vfs_open+0xa0/0xd0 [ 50.868180][ T8125] path_openat+0x144f/0x5660 [ 50.873265][ T8125] do_filp_open+0x26f/0x370 [ 50.878290][ T8125] do_open_execat+0x207/0x8e0 [ 50.883488][ T8125] __do_execve_file.isra.0+0x1966/0x2700 [ 50.889617][ T8125] __x64_sys_execve+0x8f/0xc0 [ 50.894810][ T8125] do_syscall_64+0x1a3/0x800 [ 50.899899][ T8125] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 50.906288][ T8125] [ 50.906288][ T8125] other info that might help us debug this: [ 50.906288][ T8125] [ 50.916492][ T8125] Possible unsafe locking scenario: [ 50.916492][ T8125] [ 50.923918][ T8125] CPU0 CPU1 [ 50.929260][ T8125] ---- ---- [ 50.934611][ T8125] lock(&sig->cred_guard_mutex); [ 50.939609][ T8125] lock(&pipe->mutex/1); [ 50.946431][ T8125] lock(&sig->cred_guard_mutex); [ 50.953950][ T8125] lock(&pipe->mutex/1); [ 50.958255][ T8125] [ 50.958255][ T8125] *** DEADLOCK *** [ 50.958255][ T8125] [ 50.966380][ T8125] 1 lock held by syz-executor231/8125: [ 50.971822][ T8125] #0: 00000000b00d0264 (&sig->cred_guard_mutex){+.+.}, at: __do_execve_file.isra.0+0x45d/0x2700 [ 50.982303][ T8125] [ 50.982303][ T8125] stack backtrace: [ 50.988181][ T8125] CPU: 0 PID: 8125 Comm: syz-executor231 Not tainted 5.0.0-rc1-next-20190111 #10 [ 50.997261][ T8125] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 51.007333][ T8125] Call Trace: [ 51.010606][ T8125] dump_stack+0x1db/0x2d0 [ 51.014938][ T8125] ? dump_stack_print_info.cold+0x20/0x20 [ 51.020636][ T8125] ? print_stack_trace+0x77/0xb0 [ 51.025556][ T8125] ? vprintk_func+0x86/0x189 [ 51.030130][ T8125] print_circular_bug.isra.0.cold+0x1cc/0x28f [ 51.036194][ T8125] __lock_acquire+0x2fed/0x4a10 [ 51.041027][ T8125] ? mark_held_locks+0x100/0x100 [ 51.045945][ T8125] ? lockdep_hardirqs_on+0x415/0x5d0 [ 51.051210][ T8125] ? trace_hardirqs_on+0xbd/0x310 [ 51.056218][ T8125] ? do_raw_spin_trylock+0x270/0x270 [ 51.061487][ T8125] ? unwind_get_return_address+0x61/0xa0 [ 51.067100][ T8125] ? add_lock_to_list.isra.0+0x450/0x450 [ 51.072716][ T8125] ? print_usage_bug+0xd0/0xd0 [ 51.077461][ T8125] ? depot_save_stack+0x1de/0x460 [ 51.082465][ T8125] ? __lock_is_held+0xb6/0x140 [ 51.087212][ T8125] ? save_stack+0xa9/0xd0 [ 51.091523][ T8125] lock_acquire+0x1db/0x570 [ 51.096010][ T8125] ? fifo_open+0x159/0xb00 [ 51.100449][ T8125] ? ___might_sleep+0x1e7/0x310 [ 51.105283][ T8125] ? lock_release+0xc40/0xc40 [ 51.109945][ T8125] ? fifo_open+0x159/0xb00 [ 51.114345][ T8125] ? fifo_open+0x159/0xb00 [ 51.118743][ T8125] __mutex_lock+0x12f/0x1670 [ 51.123312][ T8125] ? fifo_open+0x159/0xb00 [ 51.127709][ T8125] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 51.133938][ T8125] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 51.140178][ T8125] ? fifo_open+0x159/0xb00 [ 51.144576][ T8125] ? lockdep_init_map+0x10c/0x5b0 [ 51.149584][ T8125] ? mutex_trylock+0x2d0/0x2d0 [ 51.154333][ T8125] ? add_lock_to_list.isra.0+0x450/0x450 [ 51.159948][ T8125] ? __mutex_init+0x1f6/0x2a0 [ 51.164610][ T8125] ? psi_task_change.cold+0x1ec/0x1ec [ 51.169966][ T8125] ? fifo_open+0x2b5/0xb00 [ 51.174364][ T8125] ? find_held_lock+0x35/0x120 [ 51.179107][ T8125] ? fifo_open+0x2b5/0xb00 [ 51.183503][ T8125] ? lock_acquire+0x1db/0x570 [ 51.188181][ T8125] ? kasan_check_read+0x11/0x20 [ 51.193015][ T8125] ? do_raw_spin_unlock+0xa0/0x330 [ 51.198116][ T8125] ? do_raw_spin_trylock+0x270/0x270 [ 51.203387][ T8125] mutex_lock_nested+0x16/0x20 [ 51.208186][ T8125] ? mutex_lock_nested+0x16/0x20 [ 51.213104][ T8125] fifo_open+0x159/0xb00 [ 51.217366][ T8125] do_dentry_open+0x495/0x1230 [ 51.222112][ T8125] ? do_raw_spin_unlock+0xa0/0x330 [ 51.227204][ T8125] ? pipe_release+0x280/0x280 [ 51.231861][ T8125] ? chown_common+0x740/0x740 [ 51.236521][ T8125] ? security_inode_permission+0xd5/0x110 [ 51.242259][ T8125] ? inode_permission+0xb4/0x570 [ 51.247187][ T8125] vfs_open+0xa0/0xd0 [ 51.251165][ T8125] path_openat+0x144f/0x5660 [ 51.255738][ T8125] ? kernel_text_address+0x73/0xf0 [ 51.260832][ T8125] ? __kernel_text_address+0xd/0x40 [ 51.266011][ T8125] ? unwind_get_return_address+0x61/0xa0 [ 51.271628][ T8125] ? path_lookupat.isra.0+0xba0/0xba0 [ 51.276979][ T8125] ? save_stack+0xa9/0xd0 [ 51.281292][ T8125] ? save_stack+0x45/0xd0 [ 51.285602][ T8125] ? __kasan_kmalloc.constprop.0+0xcf/0xe0 [ 51.291388][ T8125] ? kasan_kmalloc+0x9/0x10 [ 51.295876][ T8125] ? __lock_acquire+0x572/0x4a10 [ 51.300794][ T8125] ? kmem_cache_alloc+0x12d/0x710 [ 51.305799][ T8125] ? __do_execve_file.isra.0+0x47a/0x2700 [ 51.311495][ T8125] ? __x64_sys_execve+0x8f/0xc0 [ 51.316325][ T8125] ? print_usage_bug+0xd0/0xd0 [ 51.321072][ T8125] do_filp_open+0x26f/0x370 [ 51.325559][ T8125] ? may_open_dev+0x100/0x100 [ 51.330219][ T8125] ? __sanitizer_cov_trace_const_cmp1+0x1a/0x20 [ 51.336441][ T8125] ? add_lock_to_list.isra.0+0x450/0x450 [ 51.342055][ T8125] ? add_lock_to_list.isra.0+0x450/0x450 [ 51.347667][ T8125] ? apparmor_bprm_committing_creds+0x370/0x370 [ 51.353890][ T8125] ? __do_execve_file.isra.0+0x901/0x2700 [ 51.359589][ T8125] do_open_execat+0x207/0x8e0 [ 51.364261][ T8125] ? unregister_binfmt+0x2b0/0x2b0 [ 51.369352][ T8125] ? kasan_check_read+0x11/0x20 [ 51.374191][ T8125] ? do_raw_spin_trylock+0x270/0x270 [ 51.379457][ T8125] ? __phys_addr_symbol+0x30/0x70 [ 51.384463][ T8125] __do_execve_file.isra.0+0x1966/0x2700 [ 51.390079][ T8125] ? rcu_pm_notify+0xd0/0xd0 [ 51.394649][ T8125] ? copy_strings_kernel+0x110/0x110 [ 51.399916][ T8125] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 51.406135][ T8125] ? strncpy_from_user+0x3aa/0x4e0 [ 51.411245][ T8125] ? digsig_verify.cold+0x32/0x32 [ 51.416249][ T8125] ? kmem_cache_alloc+0x341/0x710 [ 51.421257][ T8125] ? do_syscall_64+0x8c/0x800 [ 51.425952][ T8125] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 51.432180][ T8125] ? getname_flags+0x277/0x5b0 [ 51.436928][ T8125] ? trace_hardirqs_off_caller+0x300/0x300 [ 51.442716][ T8125] __x64_sys_execve+0x8f/0xc0 [ 51.447373][ T8125] do_syscall_64+0x1a3/0x800 [ 51.451943][ T8125] ? syscall_return_slowpath+0x5f0/0x5f0 [ 51.457557][ T8125] ? prepare_exit_to_usermode+0x232/0x3b0 [ 51.463345][ T8125] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 51.468878][ T8125] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 51.474752][ T8125] RIP: 0033:0x440139 [ 51.478629][ T8125] 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 [ 51.498215][ T8125] RSP: 002b:00007ffc65a6dcf8 EFLAGS: 00000217 ORIG_RAX: 000000000000003b [ 51.506610][ T8125] RAX: ffffffffffffffda RBX: 0030656c69662f2e RCX: 0000000000440139 [ 51.514563][ T8125] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000240 [ 51.522515][ T8125] RBP: 00000000006ca018 R08: 0000000000000000 R09: 0000000000000000 [ 51.530468][ T8125] R10: 0000000000000000 R11: 0000000000000217 R12: 00000000004019c0 [ 51.538426][ T8125] R13: 0000000000401a50 R14: 0000000000000000 R15: 0000000000000000