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-7,10.128.15.209' (ECDSA) to the list of known hosts. 2017/08/31 07:56:36 parsed 1 programs 2017/08/31 07:56:36 executed programs: 0 syzkaller login: [ 45.305855] [ 45.307537] ============================================ [ 45.312953] WARNING: possible recursive locking detected [ 45.318367] 4.13.0-rc7-next-20170829+ #11 Not tainted [ 45.323518] -------------------------------------------- [ 45.328931] syz-executor0/4472 is trying to acquire lock: [ 45.334440] (sk_lock-AF_KCM){+.+.}, at: [] kcm_sendpage+0x16e/0x1880 [ 45.342561] [ 45.342561] but task is already holding lock: [ 45.348496] (sk_lock-AF_KCM){+.+.}, at: [] kcm_sendmsg+0x1ec/0x2200 [ 45.356521] [ 45.356521] other info that might help us debug this: [ 45.363148] Possible unsafe locking scenario: [ 45.363148] [ 45.369166] CPU0 [ 45.371711] ---- [ 45.374257] lock(sk_lock-AF_KCM); [ 45.377858] lock(sk_lock-AF_KCM); [ 45.381450] [ 45.381450] *** DEADLOCK *** [ 45.381450] [ 45.387471] May be due to missing lock nesting notation [ 45.387471] [ 45.394367] 1 lock held by syz-executor0/4472: [ 45.398910] #0: (sk_lock-AF_KCM){+.+.}, at: [] kcm_sendmsg+0x1ec/0x2200 [ 45.407366] [ 45.407366] stack backtrace: [ 45.411829] CPU: 0 PID: 4472 Comm: syz-executor0 Not tainted 4.13.0-rc7-next-20170829+ #11 [ 45.420192] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 45.429508] Call Trace: [ 45.432063] dump_stack+0x194/0x257 [ 45.435656] ? arch_local_irq_restore+0x53/0x53 [ 45.440293] __lock_acquire+0x1232/0x4620 [ 45.444407] ? unwind_next_frame.part.6+0x1ae/0xc70 [ 45.449392] ? debug_check_no_locks_freed+0x3d0/0x3d0 [ 45.454551] ? __unwind_start+0x169/0x330 [ 45.458666] ? unwind_get_return_address+0x50/0xa0 [ 45.463563] ? __save_stack_trace+0x61/0xd0 [ 45.467851] ? __vfs_write+0x68a/0x970 [ 45.471703] ? save_stack_trace+0x16/0x20 [ 45.475815] ? __lock_acquire+0x20f4/0x4620 [ 45.480100] ? __unwind_start+0x169/0x330 [ 45.484214] ? unwind_get_return_address+0x61/0xa0 [ 45.489108] ? __save_stack_trace+0x61/0xd0 [ 45.493398] ? debug_check_no_locks_freed+0x3d0/0x3d0 [ 45.498555] ? save_stack_trace+0x16/0x20 [ 45.502666] ? __lock_acquire+0x20f4/0x4620 [ 45.506955] ? check_noncircular+0x20/0x20 [ 45.511160] ? check_noncircular+0x20/0x20 [ 45.515362] ? find_held_lock+0x39/0x1d0 [ 45.519393] ? lock_downgrade+0x990/0x990 [ 45.523510] lock_acquire+0x1d5/0x580 [ 45.527274] ? kcm_sendpage+0x16e/0x1880 [ 45.531304] ? lock_release+0xd70/0xd70 [ 45.535246] ? check_same_owner+0x320/0x320 [ 45.539532] ? print_usage_bug+0x480/0x480 [ 45.543735] ? lock_sock_nested+0x44/0x110 [ 45.547934] lock_sock_nested+0xc2/0x110 [ 45.551961] ? kcm_sendpage+0x16e/0x1880 [ 45.555986] kcm_sendpage+0x16e/0x1880 [ 45.559841] ? kcm_write_msgs+0x1b80/0x1b80 [ 45.564130] ? kcm_write_msgs+0xce1/0x1b80 [ 45.568332] ? find_held_lock+0x39/0x1d0 [ 45.572360] ? mark_held_locks+0xb2/0x100 [ 45.576473] ? __local_bh_enable_ip+0x9d/0x160 [ 45.581021] ? kcm_write_msgs+0x1b80/0x1b80 [ 45.585309] kernel_sendpage+0x8d/0xe0 [ 45.589163] kcm_write_msgs+0x404/0x1b80 [ 45.593191] ? lock_release+0xd70/0xd70 [ 45.597133] ? kcm_release+0x860/0x860 [ 45.600984] ? kasan_check_write+0x14/0x20 [ 45.605184] ? copyin+0x91/0xb0 [ 45.608433] ? check_stack_object+0x140/0x140 [ 45.612891] ? __local_bh_enable_ip+0x9d/0x160 [ 45.617437] ? iov_iter_advance+0x13f0/0x13f0 [ 45.621896] ? trace_hardirqs_on+0xd/0x10 [ 45.626014] kcm_sendmsg+0x1446/0x2200 [ 45.629866] ? find_held_lock+0x39/0x1d0 [ 45.633895] ? kcm_sendpage+0x1880/0x1880 [ 45.638791] ? sock_has_perm+0x29c/0x400 [ 45.642818] ? selinux_tun_dev_create+0xc0/0xc0 [ 45.647453] ? lock_release+0xd70/0xd70 [ 45.651395] ? selinux_socket_sendmsg+0x36/0x40 [ 45.656027] ? security_socket_sendmsg+0x89/0xb0 [ 45.660749] ? kcm_sendpage+0x1880/0x1880 [ 45.664862] sock_sendmsg+0xca/0x110 [ 45.668546] sock_write_iter+0x320/0x5e0 [ 45.672572] ? sock_sendmsg+0x110/0x110 [ 45.676517] ? iov_iter_init+0xaf/0x1d0 [ 45.680460] __vfs_write+0x68a/0x970 [ 45.684152] ? default_llseek+0x2a0/0x2a0 [ 45.688261] ? selinux_capset+0x100/0x100 [ 45.692374] ? _cond_resched+0x14/0x30 [ 45.696231] ? selinux_file_permission+0x82/0x460 [ 45.701041] ? rw_verify_area+0xe5/0x2b0 [ 45.705067] ? __fdget_raw+0x20/0x20 [ 45.708747] vfs_write+0x18f/0x510 [ 45.712252] SyS_write+0xef/0x220 [ 45.715672] ? SyS_read+0x220/0x220 [ 45.719263] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 45.724244] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 45.728968] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 45.733689] RIP: 0033:0x451e59 [ 45.736845] RSP: 002b:00007f3b46a99c08 EFLAGS: 00000216 ORIG_RAX: 0000000000000001 [ 45.744525] RAX: ffffffffffffffda RBX: 0000000000718000 RCX: 0000000000451e59 [ 45.751767] RDX: 000000000000009a RSI: 0000000020ef4000 RDI: 0000000000000008 [ 45.759000] RBP: 0000000000000086 R08: 0000000000000000 R09: 0000000000000000 [ 45.766235] R10: 0000000000000000 R11: 0000000000000216 R12: 00000000004b70e7 [ 45.773472] R13: 00000000ffffffff R14: 0000000000000005 R15: 0000000020b4cfd0