[....] Starting enhanced syslogd: rsyslogd[ 12.546003] audit: type=1400 audit(1513528633.721:4): avc: denied { syslog } for pid=3172 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 mcstransd: [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] 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-386-3,10.128.15.243' (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 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program 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: [ 30.691629] [ 30.693269] ====================================================== [ 30.699554] [ INFO: possible circular locking dependency detected ] [ 30.705929] 4.9.69-g3f1d77c #4 Not tainted [ 30.710126] ------------------------------------------------------- [ 30.716493] syzkaller507736/6660 is trying to acquire lock: [ 30.722165] (&p->lock){+.+.+.}, at: [] seq_read+0xdd/0x1290 [ 30.729840] but task is already holding lock: [ 30.734468] (&pipe->mutex/1){+.+.+.}, at: [] pipe_lock+0x56/0x70 [ 30.742671] which lock already depends on the new lock. [ 30.742671] [ 30.749645] [ 30.749645] the existing dependency chain (in reverse order) is: [ 30.757234] -> #2 (&pipe->mutex/1){+.+.+.}: [ 30.762255] lock_acquire+0x12e/0x410 [ 30.766539] mutex_lock_nested+0xbb/0x870 [ 30.771169] fifo_open+0x15c/0xa30 [ 30.775192] do_dentry_open+0x607/0xc60 [ 30.779648] vfs_open+0x105/0x220 [ 30.783586] path_openat+0x5ac/0x2910 [ 30.787867] do_filp_open+0x197/0x290 [ 30.792151] do_open_execat+0xfa/0x4d0 [ 30.796522] do_execveat_common.isra.37+0x6d6/0x1f10 [ 30.802108] compat_SyS_execve+0x48/0x60 [ 30.806653] do_fast_syscall_32+0x2f7/0x890 [ 30.811459] entry_SYSENTER_compat+0x51/0x60 [ 30.816347] -> #1 (&sig->cred_guard_mutex){+.+.+.}: [ 30.821949] lock_acquire+0x12e/0x410 [ 30.826241] mutex_lock_killable_nested+0xcc/0x960 [ 30.831659] do_io_accounting+0x1f4/0x860 [ 30.836299] proc_tgid_io_accounting+0x22/0x30 [ 30.841371] proc_single_show+0xf8/0x170 [ 30.845917] seq_read+0x32f/0x1290 [ 30.849942] __vfs_read+0x103/0x670 [ 30.854056] vfs_read+0x11e/0x380 [ 30.857992] SyS_read+0xd9/0x1b0 [ 30.861848] do_fast_syscall_32+0x2f7/0x890 [ 30.866652] entry_SYSENTER_compat+0x51/0x60 [ 30.871541] -> #0 (&p->lock){+.+.+.}: [ 30.875924] __lock_acquire+0x2bf9/0x3640 [ 30.880554] lock_acquire+0x12e/0x410 [ 30.884846] mutex_lock_nested+0xbb/0x870 [ 30.889477] seq_read+0xdd/0x1290 [ 30.893413] do_loop_readv_writev.part.17+0x141/0x1e0 [ 30.899085] do_readv_writev+0x520/0x750 [ 30.903629] vfs_readv+0x84/0xc0 [ 30.907480] default_file_splice_read+0x43f/0x7a0 [ 30.912809] do_splice_to+0x10a/0x160 [ 30.917092] SyS_splice+0xf5f/0x1520 [ 30.921290] do_fast_syscall_32+0x2f7/0x890 [ 30.926093] entry_SYSENTER_compat+0x51/0x60 [ 30.930982] [ 30.930982] other info that might help us debug this: [ 30.930982] [ 30.939091] Chain exists of: &p->lock --> &sig->cred_guard_mutex --> &pipe->mutex/1 [ 30.948061] Possible unsafe locking scenario: [ 30.948061] [ 30.954079] CPU0 CPU1 [ 30.958708] ---- ---- [ 30.963336] lock(&pipe->mutex/1); [ 30.967261] lock(&sig->cred_guard_mutex); [ 30.974280] lock(&pipe->mutex/1); [ 30.980732] lock(&p->lock); [ 30.984042] [ 30.984042] *** DEADLOCK *** [ 30.984042] [ 30.990070] 1 lock held by syzkaller507736/6660: [ 30.994785] #0: (&pipe->mutex/1){+.+.+.}, at: [] pipe_lock+0x56/0x70 [ 31.003540] [ 31.003540] stack backtrace: [ 31.007999] CPU: 0 PID: 6660 Comm: syzkaller507736 Not tainted 4.9.69-g3f1d77c #4 [ 31.015580] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 31.024902] ffff8801c53672a8 ffffffff81d90a29 ffffffff85356b40 ffffffff8538ab30 [ 31.032845] ffffffff85390800 ffff8801d811d0d8 ffff8801d811c800 ffff8801c53672f0 [ 31.040794] ffffffff81235c41 ffff8801d811d0d8 00000000d811d0b0 ffff8801d811d0d8 [ 31.048733] Call Trace: [ 31.051284] [] dump_stack+0xc1/0x128 [ 31.056611] [] print_circular_bug+0x271/0x310 [ 31.062719] [] __lock_acquire+0x2bf9/0x3640 [ 31.068655] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 31.075633] [] ? _raw_spin_unlock_irqrestore+0x45/0x70 [ 31.082523] [] ? depot_save_stack+0x3b1/0x4a0 [ 31.088632] [] ? __lock_is_held+0xa1/0xf0 [ 31.094393] [] lock_acquire+0x12e/0x410 [ 31.099979] [] ? seq_read+0xdd/0x1290 [ 31.105392] [] ? seq_read+0xdd/0x1290 [ 31.110804] [] mutex_lock_nested+0xbb/0x870 [ 31.116736] [] ? seq_read+0xdd/0x1290 [ 31.122148] [] ? mutex_lock_killable_nested+0x960/0x960 [ 31.129123] [] ? __lock_is_held+0xa1/0xf0 [ 31.134882] [] seq_read+0xdd/0x1290 [ 31.140127] [] ? __lock_is_held+0xa1/0xf0 [ 31.145888] [] ? seq_escape+0x200/0x200 [ 31.151477] [] ? fsnotify+0x86/0xf30 [ 31.156818] [] ? fsnotify+0xf30/0xf30 [ 31.162237] [] ? avc_policy_seqno+0x9/0x20 [ 31.168084] [] do_loop_readv_writev.part.17+0x141/0x1e0 [ 31.175061] [] ? security_file_permission+0x89/0x1e0 [ 31.181777] [] ? seq_escape+0x200/0x200 [ 31.187362] [] ? seq_escape+0x200/0x200 [ 31.192947] [] do_readv_writev+0x520/0x750 [ 31.198794] [] ? vfs_write+0x530/0x530 [ 31.204294] [] ? kasan_unpoison_shadow+0x35/0x50 [ 31.210663] [] ? push_pipe+0x372/0x770 [ 31.216161] [] ? sanity+0x1ff/0x610 [ 31.221401] [] ? iov_iter_get_pages_alloc+0x2c7/0xf10 [ 31.228206] [] vfs_readv+0x84/0xc0 [ 31.233389] [] default_file_splice_read+0x43f/0x7a0 [ 31.240018] [] ? do_splice_direct+0x270/0x270 [ 31.246127] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 31.253115] [] ? rw_verify_area+0xe5/0x2b0 [ 31.258961] [] ? do_splice_direct+0x270/0x270 [ 31.265068] [] do_splice_to+0x10a/0x160 [ 31.270655] [] SyS_splice+0xf5f/0x1520 [ 31.276155] [] ? compat_SyS_vmsplice+0x240/0x240 [ 31.282523] [] ? do_fast_syscall_32+0xcf/0x890 executing program executing program [ 31.288717] [] ? compat_SyS_vmsplice+0x240/0x240 [ 31.295083] [] do_fast_syscall_32+0x2f7/0x890 [ 31.301191] [] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 31.307822] [] entry_SYSENTER_compat+0x51/0x60 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program