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-net-kasan-gce-4,10.128.0.3' (ECDSA) to the list of known hosts. 2017/08/30 16:40:59 parsed 1 programs 2017/08/30 16:40:59 executed programs: 0 syzkaller login: [ 37.473160] [ 37.473484] ============================================ [ 37.474322] WARNING: possible recursive locking detected [ 37.475129] 4.13.0-rc6+ #29 Not tainted [ 37.475722] -------------------------------------------- [ 37.476511] syz-executor2/5642 is trying to acquire lock: [ 37.477495] (sk_lock-AF_KCM){+.+.+.}, at: [] kcm_sendpage+0x16e/0x1880 [ 37.478809] [ 37.478809] but task is already holding lock: [ 37.479798] (sk_lock-AF_KCM){+.+.+.}, at: [] kcm_sendmsg+0x1ec/0x2200 [ 37.481111] [ 37.481111] other info that might help us debug this: [ 37.482196] Possible unsafe locking scenario: [ 37.482196] [ 37.483237] CPU0 [ 37.483658] ---- [ 37.484122] lock(sk_lock-AF_KCM); [ 37.484692] lock(sk_lock-AF_KCM); [ 37.485183] [ 37.485183] *** DEADLOCK *** [ 37.485183] [ 37.486030] May be due to missing lock nesting notation [ 37.486030] [ 37.487002] 1 lock held by syz-executor2/5642: [ 37.487628] #0: (sk_lock-AF_KCM){+.+.+.}, at: [] kcm_sendmsg+0x1ec/0x2200 [ 37.488803] [ 37.488803] stack backtrace: [ 37.489425] CPU: 0 PID: 5642 Comm: syz-executor2 Not tainted 4.13.0-rc6+ #29 [ 37.490394] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 37.491641] Call Trace: [ 37.492007] dump_stack+0x194/0x257 [ 37.492512] ? arch_local_irq_restore+0x53/0x53 [ 37.493165] __lock_acquire+0xfac/0x3dc0 [ 37.493728] ? print_usage_bug+0x480/0x480 [ 37.497945] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 37.503111] ? select_task_rq_fair+0xeba/0x2ac0 [ 37.507754] ? should_fail+0x23b/0xa40 [ 37.511612] ? print_usage_bug+0x480/0x480 [ 37.515818] ? check_noncircular+0x20/0x20 [ 37.520033] ? find_held_lock+0x30/0x1d0 [ 37.524072] ? check_noncircular+0x20/0x20 [ 37.528279] ? find_held_lock+0x35/0x1d0 [ 37.532320] ? find_held_lock+0x35/0x1d0 [ 37.536363] ? check_noncircular+0x20/0x20 [ 37.540574] ? check_noncircular+0x20/0x20 [ 37.544786] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 37.549950] ? find_held_lock+0x35/0x1d0 [ 37.553984] lock_acquire+0x1d5/0x580 [ 37.557760] ? lock_acquire+0x1d5/0x580 [ 37.561710] ? kcm_sendpage+0x16e/0x1880 [ 37.565746] ? lock_release+0xa40/0xa40 [ 37.569694] ? check_same_owner+0x320/0x320 [ 37.573987] ? print_usage_bug+0x480/0x480 [ 37.578197] ? lock_sock_nested+0x44/0x110 [ 37.582406] lock_sock_nested+0xc2/0x110 [ 37.586439] ? kcm_sendpage+0x16e/0x1880 [ 37.590473] kcm_sendpage+0x16e/0x1880 [ 37.594352] ? __vfs_write+0x684/0x970 [ 37.598211] ? vfs_write+0x189/0x510 [ 37.601899] ? SyS_write+0xef/0x220 [ 37.605498] ? entry_SYSCALL_64_fastpath+0x1f/0xbe [ 37.610398] ? __lock_is_held+0xb6/0x140 [ 37.614435] ? kcm_write_msgs+0x1b80/0x1b80 [ 37.618730] ? kcm_write_msgs+0xfa7/0x1b80 [ 37.622938] ? lock_downgrade+0x990/0x990 [ 37.627071] ? mark_held_locks+0xaf/0x100 [ 37.631195] ? __local_bh_enable_ip+0x9d/0x160 [ 37.635750] ? kcm_write_msgs+0x1b80/0x1b80 [ 37.640049] kernel_sendpage+0x8d/0xe0 [ 37.643914] kcm_write_msgs+0x404/0x1b80 [ 37.647948] ? lock_release+0xa40/0xa40 [ 37.651902] ? kcm_release+0x860/0x860 [ 37.655761] ? kasan_check_write+0x14/0x20 [ 37.659970] ? copyin+0x91/0xb0 [ 37.663229] ? check_stack_object+0x140/0x140 [ 37.667697] ? __local_bh_enable_ip+0x9d/0x160 [ 37.672261] ? iov_iter_advance+0x13f0/0x13f0 [ 37.676727] ? trace_hardirqs_on+0xd/0x10 [ 37.680850] kcm_sendmsg+0x1446/0x2200 [ 37.684713] ? get_futex_key+0x1d50/0x1d50 [ 37.688927] ? kcm_sendpage+0x1880/0x1880 [ 37.693046] ? lock_downgrade+0x990/0x990 [ 37.697166] ? sock_has_perm+0x29c/0x400 [ 37.701199] ? selinux_tun_dev_create+0xc0/0xc0 [ 37.705838] ? lock_release+0xa40/0xa40 [ 37.709790] ? selinux_socket_sendmsg+0x36/0x40 [ 37.714432] ? security_socket_sendmsg+0x89/0xb0 [ 37.719159] ? kcm_sendpage+0x1880/0x1880 [ 37.723280] sock_sendmsg+0xca/0x110 [ 37.726968] sock_write_iter+0x31a/0x5d0 [ 37.731012] ? sock_sendmsg+0x110/0x110 [ 37.734973] ? iov_iter_init+0xaf/0x1d0 [ 37.738922] __vfs_write+0x684/0x970 [ 37.742608] ? default_llseek+0x290/0x290 [ 37.746730] ? selinux_capset+0x100/0x100 [ 37.750861] ? selinux_file_permission+0x82/0x460 [ 37.755686] ? rw_verify_area+0xe5/0x2b0 [ 37.759723] ? __fdget_raw+0x20/0x20 [ 37.763426] vfs_write+0x189/0x510 [ 37.766946] SyS_write+0xef/0x220 [ 37.770376] ? SyS_read+0x220/0x220 [ 37.774304] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 37.779297] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 37.784038] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 37.788767] RIP: 0033:0x4512e9 [ 37.791928] RSP: 002b:00007f14c9a83c08 EFLAGS: 00000216 ORIG_RAX: 0000000000000001 [ 37.799608] RAX: ffffffffffffffda RBX: 0000000000718000 RCX: 00000000004512e9 [ 37.806850] RDX: 000000000000009a RSI: 0000000020ef4000 RDI: 0000000000000007 [ 37.814093] RBP: 0000000000000086 R08: 0000000000000000 R09: 0000000000000000 [ 37.821336] R10: 0000000000000000 R11: 0000000000000216 R12: 00000000004b70fc [ 37.828580] R13: 00000000ffffffff R14: 0000000020000000 R15: 0000000000ef8000