[....] Starting enhanced syslogd: rsyslogd[ 9.648771] audit: type=1400 audit(1513610565.969:4): avc: denied { syslog } for pid=3160 comm="rsyslogd" capability=34 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=capability2 permissive=1 [?25l[?1c7[ ok 8[?25h[?0c. [....] 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 'ci-android-49-kasan-gce-4,10.128.15.211' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program syzkaller login: [ 26.572288] [ 26.572617] ====================================================== [ 26.573447] [ INFO: possible circular locking dependency detected ] [ 26.574286] 4.9.70-g9542d2a #109 Not tainted [ 26.574868] ------------------------------------------------------- [ 26.575730] syzkaller201480/5298 is trying to acquire lock: [ 26.576509] (&p->lock){+.+.+.}, at: [] seq_read+0xdd/0x1290 [ 26.577634] but task is already holding lock: [ 26.578299] (&pipe->mutex/1){+.+.+.}, at: [] pipe_lock+0x56/0x70 [ 26.579495] which lock already depends on the new lock. [ 26.579495] [ 26.580434] [ 26.580434] the existing dependency chain (in reverse order) is: [ 26.581489] -> #2 (&pipe->mutex/1){+.+.+.}: [ 26.582265] lock_acquire+0x12e/0x410 [ 26.582866] mutex_lock_nested+0xbb/0x870 [ 26.583495] fifo_open+0x15c/0xa30 [ 26.584053] do_dentry_open+0x607/0xc60 [ 26.584647] vfs_open+0x105/0x220 [ 26.585174] path_openat+0x5ac/0x2910 [ 26.585752] do_filp_open+0x197/0x290 [ 26.586326] do_open_execat+0xfa/0x4d0 [ 26.586911] do_execveat_common.isra.37+0x6d6/0x1f10 [ 26.587649] SyS_execve+0x42/0x50 [ 26.588182] do_syscall_64+0x197/0x490 [ 26.588767] return_from_SYSCALL_64+0x0/0x7a [ 26.589415] -> #1 (&sig->cred_guard_mutex){+.+.+.}: [ 26.590237] lock_acquire+0x12e/0x410 [ 26.590810] mutex_lock_killable_nested+0xcc/0x960 [ 26.591528] lock_trace+0x44/0xc0 [ 26.592057] proc_pid_stack+0xe0/0x230 [ 26.594337] proc_single_show+0xf8/0x170 [ 26.598879] seq_read+0x32f/0x1290 [ 26.602903] __vfs_read+0x103/0x670 [ 26.607014] vfs_read+0x11e/0x380 [ 26.610949] SyS_read+0xd9/0x1b0 [ 26.614799] entry_SYSCALL_64_fastpath+0x23/0xc6 [ 26.620035] -> #0 (&p->lock){+.+.+.}: [ 26.624424] __lock_acquire+0x2bf9/0x3640 [ 26.629055] lock_acquire+0x12e/0x410 [ 26.633340] mutex_lock_nested+0xbb/0x870 [ 26.637972] seq_read+0xdd/0x1290 [ 26.641917] proc_reg_read+0xef/0x170 [ 26.646217] do_loop_readv_writev.part.17+0x141/0x1e0 [ 26.651901] do_readv_writev+0x520/0x750 [ 26.656450] vfs_readv+0x84/0xc0 [ 26.660304] default_file_splice_read+0x43f/0x7a0 [ 26.665633] do_splice_to+0x10a/0x160 [ 26.669921] SyS_splice+0xf5f/0x1520 [ 26.674131] entry_SYSCALL_64_fastpath+0x23/0xc6 [ 26.679384] [ 26.679384] other info that might help us debug this: [ 26.679384] [ 26.687498] Chain exists of: &p->lock --> &sig->cred_guard_mutex --> &pipe->mutex/1 [ 26.696505] Possible unsafe locking scenario: [ 26.696505] [ 26.702523] CPU0 CPU1 [ 26.707158] ---- ---- [ 26.711795] lock(&pipe->mutex/1); [ 26.715727] lock(&sig->cred_guard_mutex); [ 26.722762] lock(&pipe->mutex/1); [ 26.729211] lock(&p->lock); [ 26.732518] [ 26.732518] *** DEADLOCK *** [ 26.732518] [ 26.738543] 1 lock held by syzkaller201480/5298: [ 26.743266] #0: (&pipe->mutex/1){+.+.+.}, at: [] pipe_lock+0x56/0x70 [ 26.752031] [ 26.752031] stack backtrace: [ 26.756495] CPU: 1 PID: 5298 Comm: syzkaller201480 Not tainted 4.9.70-g9542d2a #109 [ 26.764253] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 26.773574] ffff8801be3272b8 ffffffff81d90a29 ffffffff85356ea0 ffffffff85389a50 [ 26.781545] ffffffff8538f210 ffff8801d8fee8d8 ffff8801d8fee000 ffff8801be327300 [ 26.789503] ffffffff81235c41 ffff8801d8fee8d8 00000000d8fee8b0 ffff8801d8fee8d8 [ 26.797474] Call Trace: [ 26.800034] [] dump_stack+0xc1/0x128 [ 26.805381] [] print_circular_bug+0x271/0x310 [ 26.811497] [] __lock_acquire+0x2bf9/0x3640 [ 26.817446] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 26.824432] [] ? __lock_is_held+0xa1/0xf0 [ 26.830203] [] lock_acquire+0x12e/0x410 [ 26.835796] [] ? seq_read+0xdd/0x1290 [ 26.841213] [] ? seq_read+0xdd/0x1290 [ 26.846633] [] mutex_lock_nested+0xbb/0x870 [ 26.852568] [] ? seq_read+0xdd/0x1290 [ 26.857985] [] ? mutex_lock_killable_nested+0x960/0x960 [ 26.864965] [] ? mark_held_locks+0xaf/0x100 [ 26.870902] [] ? depot_save_stack+0x1c5/0x4a0 [ 26.877019] [] ? _raw_spin_unlock_irqrestore+0x5a/0x70 [ 26.883918] [] ? seq_escape+0x200/0x200 [ 26.889513] [] seq_read+0xdd/0x1290 [ 26.894756] [] ? _raw_spin_unlock_irqrestore+0x45/0x70 [ 26.901647] [] ? depot_save_stack+0x3b1/0x4a0 [ 26.907758] [] ? __lock_is_held+0xa1/0xf0 [ 26.913530] [] ? seq_escape+0x200/0x200 [ 26.919126] [] ? __fsnotify_parent+0xbc/0x340 [ 26.925250] [] ? fsnotify+0x86/0xf30 [ 26.930580] [] ? fsnotify+0xf30/0xf30 [ 26.936001] [] ? seq_escape+0x200/0x200 [ 26.941594] [] proc_reg_read+0xef/0x170 [ 26.947183] [] do_loop_readv_writev.part.17+0x141/0x1e0 [ 26.954170] [] ? security_file_permission+0x89/0x1e0 [ 26.960901] [] ? proc_reg_write+0x170/0x170 [ 26.966836] [] ? proc_reg_write+0x170/0x170 [ 26.972773] [] do_readv_writev+0x520/0x750 [ 26.978623] [] ? vfs_write+0x530/0x530 [ 26.984132] [] ? kasan_unpoison_shadow+0x35/0x50 [ 26.990509] [] ? push_pipe+0x372/0x770 [ 26.996019] [] ? sanity+0x1ff/0x610 [ 27.001266] [] ? iov_iter_get_pages_alloc+0x2c7/0xf10 [ 27.008078] [] vfs_readv+0x84/0xc0 [ 27.013242] [] default_file_splice_read+0x43f/0x7a0 [ 27.019872] [] ? do_splice_direct+0x270/0x270 [ 27.025993] [] ? __fsnotify_parent+0xbc/0x340 [ 27.032111] [] ? fsnotify+0x86/0xf30 [ 27.037446] [] ? fsnotify+0xf30/0xf30 [ 27.042864] [] ? avc_policy_seqno+0x9/0x20 [ 27.048713] [] ? selinux_file_permission+0x82/0x460 [ 27.055356] [] ? security_file_permission+0x89/0x1e0 [ 27.062079] [] ? do_splice_direct+0x270/0x270 [ 27.068192] [] do_splice_to+0x10a/0x160 executing program executing program executing program [ 27.073783] [] SyS_splice+0xf5f/0x1520 [ 27.079289] [] ? compat_SyS_vmsplice+0x240/0x240 [ 27.085666] [] ? trace_hardirqs_on_caller+0x38b/0x590 [ 27.092471] [] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 27.099028] [] entry_SYSCALL_64_fastpath+0x23/0xc6 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program