[....] Starting enhanced syslogd: rsyslogd[ 9.221025] audit: type=1400 audit(1513533014.622:4): avc: denied { syslog } for pid=3162 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-1,10.128.0.47' (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 syzkaller login: [ 17.472541] [ 17.472846] ====================================================== [ 17.473693] [ INFO: possible circular locking dependency detected ] [ 17.474559] 4.9.69-g3f1d77c #108 Not tainted [ 17.475150] ------------------------------------------------------- [ 17.476004] syzkaller314931/3616 is trying to acquire lock: [ 17.476755] (&p->lock){+.+.+.}, at: [] seq_read+0xdd/0x1290 [ 17.477860] but task is already holding lock: [ 17.478476] (&pipe->mutex/1){+.+.+.}, at: [] pipe_lock+0x56/0x70 [ 17.479655] which lock already depends on the new lock. [ 17.479655] [ 17.480572] [ 17.480572] the existing dependency chain (in reverse order) is: [ 17.481566] -> #2 (&pipe->mutex/1){+.+.+.}: [ 17.482346] lock_acquire+0x12e/0x410 [ 17.482921] mutex_lock_nested+0xbb/0x870 [ 17.483551] fifo_open+0x15c/0xa30 [ 17.484096] do_dentry_open+0x607/0xc60 [ 17.484704] vfs_open+0x105/0x220 [ 17.485234] path_openat+0x5ac/0x2910 [ 17.485807] do_filp_open+0x197/0x290 [ 17.486388] do_open_execat+0xfa/0x4d0 [ 17.486991] do_execveat_common.isra.37+0x6d6/0x1f10 [ 17.487731] SyS_execve+0x42/0x50 [ 17.488260] do_syscall_64+0x197/0x490 [ 17.488873] return_from_SYSCALL_64+0x0/0x7a [ 17.489522] -> #1 (&sig->cred_guard_mutex){+.+.+.}: [ 17.490352] lock_acquire+0x12e/0x410 [ 17.490973] mutex_lock_killable_nested+0xcc/0x960 [ 17.491722] do_io_accounting+0x1f4/0x860 [ 17.492341] proc_tgid_io_accounting+0x22/0x30 [ 17.493014] proc_single_show+0xf8/0x170 [ 17.497557] seq_read+0x32f/0x1290 [ 17.501588] __vfs_read+0x103/0x670 [ 17.505707] vfs_read+0x11e/0x380 [ 17.509645] SyS_read+0xd9/0x1b0 [ 17.513503] entry_SYSCALL_64_fastpath+0x23/0xc6 [ 17.518743] executing program -> #0 (&p->lock){+.+.+.}: [ 17.523143] __lock_acquire+0x2bf9/0x3640 [ 17.527774] lock_acquire+0x12e/0x410 [ 17.532058] mutex_lock_nested+0xbb/0x870 [ 17.536689] seq_read+0xdd/0x1290 [ 17.540628] do_loop_readv_writev.part.17+0x141/0x1e0 [ 17.546302] do_readv_writev+0x520/0x750 [ 17.550846] vfs_readv+0x84/0xc0 [ 17.554697] default_file_splice_read+0x43f/0x7a0 [ 17.560022] do_splice_to+0x10a/0x160 [ 17.564310] SyS_splice+0xf5f/0x1520 [ 17.568516] entry_SYSCALL_64_fastpath+0x23/0xc6 [ 17.573758] [ 17.573758] other info that might help us debug this: [ 17.573758] [ 17.581867] Chain exists of: &p->lock --> &sig->cred_guard_mutex --> &pipe->mutex/1 [ 17.590842] Possible unsafe locking scenario: [ 17.590842] [ 17.596878] CPU0 CPU1 [ 17.601510] ---- ---- [ 17.606137] lock(&pipe->mutex/1); [ 17.610063] lock(&sig->cred_guard_mutex); executing program [ 17.617088] lock(&pipe->mutex/1); [ 17.623529] lock(&p->lock); [ 17.626839] [ 17.626839] *** DEADLOCK *** [ 17.626839] [ 17.632869] 1 lock held by syzkaller314931/3616: [ 17.637587] #0: (&pipe->mutex/1){+.+.+.}, at: [] pipe_lock+0x56/0x70 [ 17.646372] [ 17.646372] stack backtrace: [ 17.650838] CPU: 0 PID: 3616 Comm: syzkaller314931 Not tainted 4.9.69-g3f1d77c #108 [ 17.658596] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 executing program [ 17.667926] ffff8801c3ef7308 ffffffff81d90a29 ffffffff85356b40 ffffffff85389a50 [ 17.675872] ffffffff8538ff90 ffff8801c3ee38d8 ffff8801c3ee3000 ffff8801c3ef7350 [ 17.683815] ffffffff81235c41 ffff8801c3ee38d8 00000000c3ee38b0 ffff8801c3ee38d8 [ 17.691768] Call Trace: [ 17.694329] [] dump_stack+0xc1/0x128 [ 17.699661] [] print_circular_bug+0x271/0x310 [ 17.705772] [] __lock_acquire+0x2bf9/0x3640 [ 17.711709] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 executing program [ 17.718689] [] ? _raw_spin_unlock_irqrestore+0x45/0x70 [ 17.725580] [] ? depot_save_stack+0x3b1/0x4a0 [ 17.731688] [] ? __lock_is_held+0xa1/0xf0 [ 17.737451] [] lock_acquire+0x12e/0x410 [ 17.743041] [] ? seq_read+0xdd/0x1290 [ 17.748469] [] ? seq_read+0xdd/0x1290 [ 17.753893] [] mutex_lock_nested+0xbb/0x870 [ 17.759833] [] ? seq_read+0xdd/0x1290 [ 17.765251] [] ? mutex_lock_killable_nested+0x960/0x960 executing program [ 17.772227] [] ? __lock_is_held+0xa1/0xf0 [ 17.777993] [] seq_read+0xdd/0x1290 [ 17.783234] [] ? __lock_is_held+0xa1/0xf0 [ 17.788996] [] ? seq_escape+0x200/0x200 [ 17.794585] [] ? fsnotify+0x86/0xf30 [ 17.799918] [] ? fsnotify+0xf30/0xf30 [ 17.805335] [] ? avc_policy_seqno+0x9/0x20 [ 17.811192] [] do_loop_readv_writev.part.17+0x141/0x1e0 executing program [ 17.818178] [] ? security_file_permission+0x89/0x1e0 [ 17.824900] [] ? seq_escape+0x200/0x200 [ 17.830490] [] ? seq_escape+0x200/0x200 [ 17.836081] [] do_readv_writev+0x520/0x750 [ 17.841931] [] ? vfs_write+0x530/0x530 [ 17.847434] [] ? kasan_unpoison_shadow+0x35/0x50 [ 17.853804] [] ? push_pipe+0x372/0x770 [ 17.859308] [] ? sanity+0x1ff/0x610 [ 17.864904] [] ? iov_iter_get_pages_alloc+0x2c7/0xf10 [ 17.871710] [] vfs_readv+0x84/0xc0 [ 17.876871] [] default_file_splice_read+0x43f/0x7a0 [ 17.883511] [] ? do_splice_direct+0x270/0x270 [ 17.889634] [] ? security_file_permission+0x89/0x1e0 [ 17.896354] [] ? do_splice_direct+0x270/0x270 [ 17.902467] [] do_splice_to+0x10a/0x160 [ 17.908059] [] SyS_splice+0xf5f/0x1520 [ 17.913562] [] ? compat_SyS_vmsplice+0x240/0x240 executing program executing program executing program executing program executing program executing program executing program executing program [ 17.919932] [] ? trace_hardirqs_on_caller+0x38b/0x590 [ 17.926738] [] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 17.933291] [] 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 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program