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-7,10.128.15.215' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 56.931902] [ 56.932321] ============================================ [ 56.933039] WARNING: possible recursive locking detected [ 56.933801] 4.15.0-rc2-next-20171206+ #60 Not tainted [ 56.934503] -------------------------------------------- [ 56.935242] syzkaller222971/3088 is trying to acquire lock: [ 56.936013] (rtnl_mutex){+.+.}, at: [<0000000020accb75>] rtnl_lock+0x17/0x20 [ 56.936997] [ 56.936997] but task is already holding lock: [ 56.937783] (rtnl_mutex){+.+.}, at: [<0000000020accb75>] rtnl_lock+0x17/0x20 [ 56.938751] [ 56.938751] other info that might help us debug this: [ 56.939643] Possible unsafe locking scenario: [ 56.939643] [ 56.940439] CPU0 [ 56.940790] ---- [ 56.941139] lock(rtnl_mutex); [ 56.941592] lock(rtnl_mutex); [ 56.942035] [ 56.942035] *** DEADLOCK *** [ 56.942035] [ 56.942849] May be due to missing lock nesting notation [ 56.942849] [ 56.943759] 1 lock held by syzkaller222971/3088: [ 56.944387] #0: (rtnl_mutex){+.+.}, at: [<0000000020accb75>] rtnl_lock+0x17/0x20 [ 56.945403] [ 56.945403] stack backtrace: [ 56.946004] CPU: 1 PID: 3088 Comm: syzkaller222971 Not tainted 4.15.0-rc2-next-20171206+ #60 [ 56.947172] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 56.948410] Call Trace: [ 56.948785] dump_stack+0x194/0x257 [ 56.949272] ? arch_local_irq_restore+0x53/0x53 [ 56.949896] __lock_acquire+0x11cf/0x47f0 [ 56.950454] ? debug_check_no_locks_freed+0x3d0/0x3d0 [ 56.951158] ? __lock_acquire+0x6e9/0x47f0 [ 56.951726] ? debug_check_no_locks_freed+0x3d0/0x3d0 [ 56.954887] ? __kernel_text_address+0xd/0x40 [ 56.959351] ? debug_check_no_locks_freed+0x3d0/0x3d0 [ 56.964505] ? print_bfs_bug+0x70/0x70 [ 56.968358] ? save_stack_trace+0x1a/0x20 [ 56.972472] ? save_trace+0xe0/0x2b0 [ 56.976152] ? check_noncircular+0x20/0x20 [ 56.980351] ? check_noncircular+0x20/0x20 [ 56.984554] ? check_noncircular+0x20/0x20 [ 56.988763] ? __free_insn_slot+0x5c0/0x5c0 [ 56.993053] lock_acquire+0x1d5/0x580 [ 56.996818] ? rtnl_lock+0x17/0x20 [ 57.000325] ? lock_release+0xda0/0xda0 [ 57.004265] ? trace_event_raw_event_sched_switch+0x800/0x800 [ 57.010116] ? rcu_note_context_switch+0x710/0x710 [ 57.015018] ? __might_sleep+0x95/0x190 [ 57.018959] ? rtnl_lock+0x17/0x20 [ 57.022466] __mutex_lock+0x16f/0x1a80 [ 57.026320] ? rtnl_lock+0x17/0x20 [ 57.029826] ? lock_release+0xda0/0xda0 [ 57.033764] ? rtnl_lock+0x17/0x20 [ 57.037276] ? is_bpf_text_address+0xa4/0x120 [ 57.041749] ? mutex_lock_io_nested+0x1900/0x1900 [ 57.046564] ? unwind_get_return_address+0x61/0xa0 [ 57.051468] ? trace_hardirqs_off+0xd/0x10 [ 57.055677] ? _raw_spin_unlock_irqrestore+0xa6/0xba [ 57.060747] ? depot_save_stack+0x2ca/0x460 [ 57.065037] ? selinux_tun_dev_free_security+0x15/0x20 [ 57.070281] ? save_stack+0xa3/0xd0 [ 57.073875] ? save_stack+0x43/0xd0 [ 57.077468] ? kasan_slab_free+0x71/0xc0 [ 57.081498] ? kfree+0xca/0x250 [ 57.084747] ? selinux_tun_dev_free_security+0x15/0x20 [ 57.089990] ? security_tun_dev_free_security+0x48/0x80 [ 57.095319] ? tun_free_netdev+0x153/0x1f0 [ 57.099521] ? register_netdevice+0x97b/0x1010 [ 57.104070] ? __tun_chr_ioctl+0x1ca3/0x3f10 [ 57.108443] ? tun_chr_ioctl+0x2a/0x40 [ 57.112299] ? do_vfs_ioctl+0x1b1/0x1530 [ 57.116328] ? SyS_ioctl+0x8f/0xc0 [ 57.119836] ? entry_SYSCALL_64_fastpath+0x1f/0x96 [ 57.124735] ? find_held_lock+0x39/0x1d0 [ 57.128762] ? check_noncircular+0x20/0x20 [ 57.132962] ? print_usage_bug+0x3f0/0x3f0 [ 57.137164] ? lock_downgrade+0x980/0x980 [ 57.141277] ? tun_flow_flush+0x41/0xe0 [ 57.145218] ? mark_held_locks+0xb2/0x100 [ 57.149331] ? mark_held_locks+0xb2/0x100 [ 57.153444] ? kfree+0xe4/0x250 [ 57.156689] ? selinux_tun_dev_free_security+0x15/0x20 [ 57.161937] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 57.166922] ? trace_hardirqs_on+0xd/0x10 [ 57.171041] mutex_lock_nested+0x16/0x20 [ 57.175067] ? security_tun_dev_free_security+0x67/0x80 [ 57.180393] ? mutex_lock_nested+0x16/0x20 [ 57.184592] rtnl_lock+0x17/0x20 [ 57.187923] tun_free_netdev+0x158/0x1f0 [ 57.191950] ? tun_xdp+0x410/0x410 [ 57.195456] ? __lockdep_init_map+0xe4/0x650 [ 57.199831] ? tun_detach_all+0xb50/0xb50 [ 57.203945] ? tun_xdp+0x410/0x410 [ 57.207451] register_netdevice+0x97b/0x1010 [ 57.211825] ? netdev_change_features+0x100/0x100 [ 57.216632] ? round_jiffies_up+0xce/0x100 [ 57.220832] ? __round_jiffies_up_relative+0x150/0x150 [ 57.226074] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 57.230972] ? selinux_tun_dev_alloc_security+0x124/0x170 [ 57.236479] __tun_chr_ioctl+0x1ca3/0x3f10 [ 57.240682] ? __pmd_alloc+0x4e0/0x4e0 [ 57.244541] ? tun_chr_read_iter+0x1e0/0x1e0 [ 57.248921] ? avc_ss_reset+0x110/0x110 [ 57.252864] ? lock_downgrade+0x980/0x980 [ 57.256982] ? down_read_trylock+0xdb/0x170 [ 57.261287] ? trace_event_raw_event_sched_switch+0x800/0x800 [ 57.267136] ? up_read+0x1a/0x40 [ 57.270470] ? tun_chr_compat_ioctl+0x30/0x30 [ 57.274932] tun_chr_ioctl+0x2a/0x40 [ 57.278612] ? tun_chr_ioctl+0x2a/0x40 [ 57.282467] do_vfs_ioctl+0x1b1/0x1530 [ 57.286318] ? _cond_resched+0x14/0x30 [ 57.290173] ? ioctl_preallocate+0x2b0/0x2b0 [ 57.294553] ? selinux_capable+0x40/0x40 [ 57.298579] ? putname+0xf3/0x130 [ 57.301998] ? do_sys_open+0x320/0x6d0 [ 57.305852] ? security_file_ioctl+0x89/0xb0 [ 57.310226] SyS_ioctl+0x8f/0xc0 [ 57.313559] entry_SYSCALL_64_fastpath+0x1f/0x96 [ 57.318279] RIP: 0033:0x443d99 [ 57.321434] RSP: 002b:00007ffdeca82958 EFLAGS: 00000217 ORIG_RAX: 0000000000000010 [ 57.329106] RAX: ffffffffffffffda RBX: 00000000004002e0 RCX: 0000000000443d99 [ 57.336342] RDX: 0000000020533000 RSI: 00000000400454ca RDI: 0000000000000003 [ 57.343578] RBP: 00000000006ce018 R08: 0000000000000000 R09: 0000000000000000 [ 57.350812] R10: 0000000000000000 R11: 0000000000000217 R12: 0000000000401a80 [ 57.358048] R13: 0000000000401b10 R14: 0000000000000000 R15: 0000000000000000