[....] 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. [ 28.430829] kauditd_printk_skb: 7 callbacks suppressed [ 28.430841] audit: type=1800 audit(1543869043.491:29): pid=5847 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="rc.local" dev="sda1" ino=2432 res=0 [ 28.459842] audit: type=1800 audit(1543869043.491:30): pid=5847 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="rmnologin" dev="sda1" ino=2423 res=0 Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 32.584439] sshd (5986) used greatest stack depth: 15632 bytes left Warning: Permanently added '10.128.0.77' (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 [ 42.538394] ------------[ cut here ]------------ [ 42.543183] DEBUG_LOCKS_WARN_ON(depth <= 0) [ 42.543289] WARNING: CPU: 0 PID: 6033 at kernel/locking/lockdep.c:3595 lock_release+0x740/0xa10 [ 42.556425] Kernel panic - not syncing: panic_on_warn set ... [ 42.562298] CPU: 0 PID: 6033 Comm: syz-executor247 Not tainted 4.20.0-rc1-next-20181109+ #110 [ 42.570963] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 42.580296] Call Trace: [ 42.582867] dump_stack+0x244/0x39d [ 42.586474] ? dump_stack_print_info.cold.1+0x20/0x20 [ 42.591653] panic+0x2ad/0x55c [ 42.594832] ? add_taint.cold.5+0x16/0x16 [ 42.598978] ? __warn.cold.8+0x5/0x45 [ 42.602760] ? __warn+0xe8/0x1d0 [ 42.606108] ? lock_release+0x740/0xa10 [ 42.610062] __warn.cold.8+0x20/0x45 [ 42.613763] ? lock_release+0x740/0xa10 [ 42.617716] report_bug+0x254/0x2d0 [ 42.621330] do_error_trap+0x11b/0x200 [ 42.625196] do_invalid_op+0x36/0x40 [ 42.628891] ? lock_release+0x740/0xa10 [ 42.632855] invalid_op+0x14/0x20 [ 42.636289] RIP: 0010:lock_release+0x740/0xa10 [ 42.640851] Code: 03 38 d0 7c 08 84 d2 0f 85 da 02 00 00 8b 35 a7 95 b3 08 85 f6 75 15 48 c7 c6 20 66 2b 88 48 c7 c7 c0 33 2b 88 e8 10 36 e7 ff <0f> 0b 48 8b 95 e8 fe ff ff 4c 89 f7 48 8b b5 f0 fe ff ff e8 e8 58 [ 42.659738] RSP: 0018:ffff8801c1687868 EFLAGS: 00010086 [ 42.665095] RAX: 0000000000000000 RBX: 1ffff100382d0f12 RCX: 0000000000000000 [ 42.672358] RDX: 0000000000000000 RSI: ffffffff8165ba15 RDI: 0000000000000006 [ 42.679608] RBP: ffff8801c1687998 R08: ffff8801b370c340 R09: fffffbfff12b2254 [ 42.686857] R10: fffffbfff12b2254 R11: ffffffff895912a3 R12: ffffffff8b0e27a0 [ 42.694109] R13: ffff8801c1687970 R14: ffff8801b370c340 R15: ffff8801c16878b0 [ 42.701367] ? vprintk_func+0x85/0x181 [ 42.705237] ? lock_release+0x740/0xa10 [ 42.709196] ? loop_control_ioctl+0xf5/0x4e0 [ 42.713587] ? lock_downgrade+0x900/0x900 [ 42.717717] ? __radix_tree_lookup+0x3a7/0x500 [ 42.722279] ? radix_tree_insert+0x870/0x870 [ 42.726671] ? find_held_lock+0x36/0x1c0 [ 42.730728] __mutex_unlock_slowpath+0x102/0x8c0 [ 42.735465] ? __fget+0x4aa/0x740 [ 42.738897] ? wait_for_completion+0x8a0/0x8a0 [ 42.743465] ? check_preemption_disabled+0x48/0x280 [ 42.748460] ? radix_tree_lookup+0x21/0x30 [ 42.752682] ? idr_find+0x44/0x50 [ 42.756119] ? loop_lookup+0x105/0x230 [ 42.759988] ? loop_exit_cb+0x20/0x20 [ 42.763770] mutex_unlock+0xd/0x10 [ 42.767291] loop_control_ioctl+0xf5/0x4e0 [ 42.771507] ? loop_add+0xa20/0xa20 [ 42.775116] ? trace_hardirqs_off+0xb8/0x310 [ 42.779511] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 42.785036] ? loop_add+0xa20/0xa20 [ 42.788644] do_vfs_ioctl+0x1de/0x1790 [ 42.792518] ? rcu_lockdep_current_cpu_online+0x1a4/0x210 [ 42.798041] ? ioctl_preallocate+0x300/0x300 [ 42.802434] ? __fget_light+0x2e9/0x430 [ 42.806390] ? fget_raw+0x20/0x20 [ 42.809840] ? putname+0xf2/0x130 [ 42.813277] ? rcu_read_lock_sched_held+0x14f/0x180 [ 42.818276] ? kmem_cache_free+0x24f/0x290 [ 42.822493] ? __x64_sys_futex+0x47f/0x6a0 [ 42.826711] ? do_syscall_64+0x9a/0x820 [ 42.830667] ? do_syscall_64+0x9a/0x820 [ 42.834625] ? lockdep_hardirqs_on+0x3bb/0x5b0 [ 42.839496] ? security_file_ioctl+0x94/0xc0 [ 42.843909] ksys_ioctl+0xa9/0xd0 [ 42.847432] __x64_sys_ioctl+0x73/0xb0 [ 42.851303] do_syscall_64+0x1b9/0x820 [ 42.855193] ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe [ 42.860540] ? syscall_return_slowpath+0x5e0/0x5e0 [ 42.865461] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 42.870299] ? trace_hardirqs_on_caller+0x310/0x310 [ 42.875318] ? prepare_exit_to_usermode+0x291/0x3b0 [ 42.880330] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 42.885161] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 42.890416] RIP: 0033:0x446249 [ 42.893592] Code: e8 2c b3 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 2b 09 fc ff c3 66 2e 0f 1f 84 00 00 00 00 [ 42.912477] RSP: 002b:00007fda70032da8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 42.920164] RAX: ffffffffffffffda RBX: 00000000006dac28 RCX: 0000000000446249 [ 42.927412] RDX: 0000000000000000 RSI: 0000000000004c81 RDI: 0000000000000003 [ 42.934662] RBP: 00000000006dac20 R08: 0000000000000000 R09: 0000000000000000 [ 42.941908] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dac2c [ 42.949155] R13: 6f72746e6f632d70 R14: 6f6f6c2f7665642f R15: 00000000006dad2c [ 42.957320] Kernel Offset: disabled [ 42.960961] Rebooting in 86400 seconds..