INIT: Entering runlevel: 2 [info] Using makefile-style concurrent boot in runlevel 2. [....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting periodic command scheduler: cron[?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-upstream-next-kasan-gce-5,10.128.0.6' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program executing program executing program syzkaller login: [ 84.557809] [ 84.558173] ====================================================== [ 84.559055] WARNING: possible circular locking dependency detected [ 84.559903] 4.15.0-rc1-next-20171201+ #57 Not tainted [ 84.560585] ------------------------------------------------------ [ 84.561492] syzkaller485018/3189 is trying to acquire lock: [ 84.562242] (&sig->cred_guard_mutex){+.+.}, at: [<000000004ce5f5c7>] lock_trace+0x44/0xc0 [ 84.563351] [ 84.563351] but task is already holding lock: [ 84.564135] (&p->lock){+.+.}, at: [<00000000d9677bbd>] seq_read+0xd5/0x13d0 [ 84.565092] [ 84.565092] which lock already depends on the new lock. [ 84.565092] [ 84.566177] [ 84.566177] the existing dependency chain (in reverse order) is: [ 84.567172] [ 84.567172] -> #2 (&p->lock){+.+.}: [ 84.567857] lock_acquire+0x1d5/0x580 [ 84.568434] __mutex_lock+0x16f/0x1a80 [ 84.569020] mutex_lock_nested+0x16/0x20 [ 84.569627] seq_read+0xd5/0x13d0 [ 84.570159] do_iter_read+0x3db/0x5b0 [ 84.570733] vfs_readv+0x121/0x1c0 [ 84.571274] default_file_splice_read+0x508/0xae0 [ 84.571982] do_splice_to+0x110/0x170 [ 84.572557] SyS_splice+0x11a8/0x1630 [ 84.573132] entry_SYSCALL_64_fastpath+0x1f/0x96 [ 84.573828] [ 84.573828] -> #1 (&pipe->mutex/1){+.+.}: [ 84.574608] lock_acquire+0x1d5/0x580 [ 84.575235] __mutex_lock+0x16f/0x1a80 [ 84.575832] mutex_lock_nested+0x16/0x20 [ 84.576475] fifo_open+0x15c/0xa40 [ 84.577032] do_dentry_open+0x682/0xd70 [ 84.577631] vfs_open+0x107/0x230 [ 84.579629] path_openat+0x1157/0x3530 [ 84.584000] do_filp_open+0x25b/0x3b0 [ 84.588290] do_open_execat+0x1b9/0x5c0 [ 84.592749] do_execveat_common.isra.30+0x90c/0x22a0 [ 84.598336] SyS_execve+0x39/0x50 [ 84.602277] do_syscall_64+0x26c/0x920 executing program executing program [ 84.606650] return_from_SYSCALL_64+0x0/0x75 [ 84.611543] [ 84.611543] -> #0 (&sig->cred_guard_mutex){+.+.}: [ 84.617936] __lock_acquire+0x3498/0x47f0 [ 84.622570] lock_acquire+0x1d5/0x580 [ 84.626858] __mutex_lock+0x16f/0x1a80 [ 84.631231] mutex_lock_killable_nested+0x16/0x20 [ 84.636558] lock_trace+0x44/0xc0 [ 84.640494] proc_pid_syscall+0xa3/0x550 [ 84.645042] proc_single_show+0xf8/0x170 [ 84.649588] seq_read+0x385/0x13d0 [ 84.653610] do_iter_read+0x3db/0x5b0 [ 84.657896] vfs_readv+0x121/0x1c0 [ 84.661922] default_file_splice_read+0x508/0xae0 [ 84.667250] do_splice_to+0x110/0x170 [ 84.671536] SyS_splice+0x11a8/0x1630 [ 84.675824] entry_SYSCALL_64_fastpath+0x1f/0x96 [ 84.681064] [ 84.681064] other info that might help us debug this: [ 84.681064] [ 84.689178] Chain exists of: [ 84.689178] &sig->cred_guard_mutex --> &pipe->mutex/1 --> &p->lock [ 84.689178] [ 84.699984] Possible unsafe locking scenario: [ 84.699984] executing program executing program [ 84.706014] CPU0 CPU1 [ 84.710645] ---- ---- [ 84.715275] lock(&p->lock); [ 84.718344] lock(&pipe->mutex/1); [ 84.724463] lock(&p->lock); [ 84.730050] lock(&sig->cred_guard_mutex); [ 84.734335] [ 84.734335] *** DEADLOCK *** [ 84.734335] [ 84.740367] 2 locks held by syzkaller485018/3189: [ 84.745192] #0: (&pipe->mutex/1){+.+.}, at: [<000000002b08f5a4>] pipe_lock+0x56/0x70 [ 84.753226] #1: (&p->lock){+.+.}, at: [<00000000d9677bbd>] seq_read+0xd5/0x13d0 [ 84.760818] [ 84.760818] stack backtrace: [ 84.765280] CPU: 1 PID: 3189 Comm: syzkaller485018 Not tainted 4.15.0-rc1-next-20171201+ #57 [ 84.773827] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 84.783146] Call Trace: [ 84.785699] dump_stack+0x194/0x257 [ 84.789290] ? arch_local_irq_restore+0x53/0x53 [ 84.793929] print_circular_bug+0x42d/0x610 [ 84.798217] ? save_stack_trace+0x1a/0x20 [ 84.802341] check_prev_add+0x666/0x15f0 [ 84.806368] ? lock_release+0xda0/0xda0 [ 84.810307] ? copy_trace+0x150/0x150 [ 84.814083] ? check_usage+0xb60/0xb60 [ 84.817937] ? check_usage_forwards+0x410/0x410 [ 84.822574] ? kernel_text_address+0x102/0x140 [ 84.827125] __lock_acquire+0x3498/0x47f0 [ 84.831239] ? __lock_acquire+0x3498/0x47f0 [ 84.835526] ? add_lock_to_list.isra.32+0x1e9/0x4e0 [ 84.840509] ? debug_check_no_locks_freed+0x3d0/0x3d0 [ 84.845667] ? check_prev_add+0x318/0x15f0 [ 84.849866] ? check_prev_add+0x318/0x15f0 [ 84.854064] ? copy_trace+0x150/0x150 executing program executing program [ 84.857832] ? print_usage_bug+0x3f0/0x3f0 [ 84.862029] ? __lock_acquire+0x6e9/0x47f0 [ 84.866230] ? __lock_acquire+0x6e9/0x47f0 [ 84.870429] ? print_usage_bug+0x3f0/0x3f0 [ 84.874630] ? __lock_acquire+0x6e9/0x47f0 [ 84.878830] ? check_noncircular+0x20/0x20 [ 84.883036] ? debug_check_no_locks_freed+0x3d0/0x3d0 [ 84.888191] ? __lock_acquire+0x6e9/0x47f0 [ 84.892390] ? debug_check_no_locks_freed+0x3d0/0x3d0 [ 84.897543] ? debug_check_no_locks_freed+0x3d0/0x3d0 [ 84.902697] lock_acquire+0x1d5/0x580 [ 84.906475] ? lock_trace+0x44/0xc0 [ 84.910067] ? debug_check_no_locks_freed+0x3d0/0x3d0 [ 84.915220] ? lock_release+0xda0/0xda0 [ 84.919161] ? trace_event_raw_event_sched_switch+0x800/0x800 [ 84.925011] ? rcu_note_context_switch+0x710/0x710 [ 84.929906] ? __might_sleep+0x95/0x190 [ 84.933843] ? lock_trace+0x44/0xc0 [ 84.937435] __mutex_lock+0x16f/0x1a80 [ 84.941287] ? lock_trace+0x44/0xc0 [ 84.944880] ? lock_trace+0x44/0xc0 [ 84.948472] ? __free_insn_slot+0x5c0/0x5c0 [ 84.952758] ? mutex_lock_io_nested+0x1900/0x1900 executing program executing program [ 84.957565] ? __lock_acquire+0x6e9/0x47f0 [ 84.961764] ? find_held_lock+0x39/0x1d0 [ 84.965794] ? debug_check_no_locks_freed+0x3d0/0x3d0 [ 84.970962] ? rcutorture_record_progress+0x10/0x10 [ 84.975945] ? lock_release+0xda0/0xda0 [ 84.979886] ? is_bpf_text_address+0xa4/0x120 [ 84.984346] ? mark_held_locks+0xb2/0x100 [ 84.988458] ? _raw_spin_unlock_irqrestore+0x31/0xba [ 84.993535] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 84.998515] ? trace_hardirqs_on+0xd/0x10 [ 85.002629] ? check_noncircular+0x20/0x20 [ 85.006829] ? depot_save_stack+0x2ca/0x460 [ 85.011120] ? save_stack+0xa3/0xd0 [ 85.014720] ? save_stack+0x43/0xd0 [ 85.018313] ? kasan_kmalloc+0xad/0xe0 [ 85.022169] ? __kmalloc_node+0x47/0x70 [ 85.026112] ? check_noncircular+0x20/0x20 [ 85.030312] ? vfs_readv+0x121/0x1c0 [ 85.033990] ? default_file_splice_read+0x508/0xae0 [ 85.038974] mutex_lock_killable_nested+0x16/0x20 [ 85.043781] ? mutex_lock_killable_nested+0x16/0x20 [ 85.048760] lock_trace+0x44/0xc0 [ 85.052191] proc_pid_syscall+0xa3/0x550 [ 85.056219] ? proc_pid_stack+0x340/0x340 [ 85.060331] ? __lock_is_held+0xbc/0x140 [ 85.064359] ? rcu_read_lock_held+0xa9/0xc0 [ 85.068648] ? pid_task+0xf7/0x1a0 [ 85.072159] ? kasan_kmalloc+0xad/0xe0 [ 85.076013] proc_single_show+0xf8/0x170 [ 85.080044] seq_read+0x385/0x13d0 [ 85.083551] ? seq_lseek+0x3c0/0x3c0 [ 85.087231] ? selinux_file_permission+0x82/0x460 [ 85.092039] ? security_file_permission+0x89/0x1f0 [ 85.096932] ? rw_verify_area+0xe5/0x2b0 [ 85.100958] do_iter_read+0x3db/0x5b0 [ 85.104725] ? dup_iter+0x260/0x260 executing program executing program [ 85.108317] vfs_readv+0x121/0x1c0 [ 85.111821] ? compat_rw_copy_check_uvector+0x2e0/0x2e0 [ 85.117149] ? lock_acquire+0x1d5/0x580 [ 85.121087] ? pipe_lock+0x56/0x70 [ 85.124593] ? lock_release+0xda0/0xda0 [ 85.128534] ? trace_event_raw_event_sched_switch+0x800/0x800 [ 85.134387] ? rcu_note_context_switch+0x710/0x710 [ 85.139369] ? __might_sleep+0x95/0x190 [ 85.143307] ? pipe_lock+0x56/0x70 [ 85.146814] ? __mutex_lock+0x16f/0x1a80 [ 85.150839] ? pipe_lock+0x56/0x70 [ 85.154345] default_file_splice_read+0x508/0xae0 [ 85.159153] ? default_file_splice_read+0x508/0xae0 [ 85.164135] ? do_splice_direct+0x3d0/0x3d0 [ 85.168423] ? __lock_is_held+0xbc/0x140 [ 85.172463] ? __lock_is_held+0xbc/0x140 [ 85.176493] ? fsnotify+0x7b3/0x1140 [ 85.180178] ? security_file_permission+0x89/0x1f0 [ 85.185074] ? do_splice_direct+0x3d0/0x3d0 [ 85.189360] do_splice_to+0x110/0x170 [ 85.193127] ? do_splice_to+0x110/0x170 [ 85.197067] SyS_splice+0x11a8/0x1630 [ 85.200834] ? lockdep_sys_exit+0x47/0xf0 [ 85.204952] ? compat_SyS_vmsplice+0x250/0x250 executing program executing program [ 85.209498] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 85.214480] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 85.219203] entry_SYSCALL_64_fastpath+0x1f/0x96 [ 85.223922] RIP: 0033:0x446bb9 [ 85.227078] RSP: 002b:00007f3977fa9cf8 EFLAGS: 00000212 ORIG_RAX: 0000000000000113 [ 85.234748] RAX: ffffffffffffffda RBX: 00007f3977faa700 RCX: 0000000000446bb9 [ 85.241983] RDX: 0000000000000005 RSI: 0000000000000000 RDI: 0000000000000006 [ 85.249219] RBP: 00007ffe29b9f8c0 R08: 000000000000a3ea R09: 0000000000000000 executing program executing program executing program executing program executing program executing program [ 85.256451] R10: 0000000000000000 R11: 0000000000000212 R12: 0000000000000000 [ 85.263684] R13: 00007ffe29b9f8bf R14: 00007f3977faa9c0 R15: 0000000000000000 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program