unregister_netdevice: waiting for syz0 to become free. Usage count = 2 INFO: task syz-executor0:22280 blocked for more than 120 seconds. Not tainted 4.15.0-rc7+ #187 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor0 D24976 22280 4793 0x00000004 Call Trace: context_switch kernel/sched/core.c:2799 [inline] __schedule+0x8eb/0x2060 kernel/sched/core.c:3375 schedule+0xf5/0x430 kernel/sched/core.c:3434 schedule_preempt_disabled+0x10/0x20 kernel/sched/core.c:3492 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0xaad/0x1a80 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 sock_ioctl+0x367/0x440 net/socket.c:1020 vfs_ioctl fs/ioctl.c:46 [inline] do_vfs_ioctl+0x1b1/0x1520 fs/ioctl.c:686 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692 entry_SYSCALL_64_fastpath+0x23/0x9a RIP: 0033:0x452cf9 RSP: 002b:00007f7c2257fc58 EFLAGS: 00000212 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f7c22580700 RCX: 0000000000452cf9 RDX: 0000000020ec4ff0 RSI: 00000000000089a1 RDI: 0000000000000016 RBP: 0000000000a2f870 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000212 R12: 0000000000000000 R13: 0000000000a2f7ef R14: 00007f7c225809c0 R15: 0000000000000002 Showing all locks held in the system: 2 locks held by khungtaskd/746: #0: (rcu_read_lock){....}, at: [<000000006bed6af1>] check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: (rcu_read_lock){....}, at: [<000000006bed6af1>] watchdog+0x1c5/0xd60 kernel/hung_task.c:249 #1: (tasklist_lock){.+.+}, at: [<0000000013242c51>] debug_show_all_locks+0xd3/0x400 kernel/locking/lockdep.c:4464 1 lock held by rsyslogd/3502: #0: (&f->f_pos_lock){+.+.}, at: [<0000000025693af2>] __fdget_pos+0x12b/0x190 fs/file.c:770 2 locks held by getty/3623: #0: (&tty->ldisc_sem){++++}, at: [<00000000cfb0af74>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000f12286e7>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/3624: #0: (&tty->ldisc_sem){++++}, at: [<00000000cfb0af74>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000f12286e7>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/3625: #0: (&tty->ldisc_sem){++++}, at: [<00000000cfb0af74>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000f12286e7>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/3626: #0: (&tty->ldisc_sem){++++}, at: [<00000000cfb0af74>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000f12286e7>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/3627: #0: (&tty->ldisc_sem){++++}, at: [<00000000cfb0af74>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000f12286e7>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/3628: #0: (&tty->ldisc_sem){++++}, at: [<00000000cfb0af74>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000f12286e7>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/3629: #0: (&tty->ldisc_sem){++++}, at: [<00000000cfb0af74>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000f12286e7>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 1 lock held by syz-executor0/22268: #0: (br_ioctl_mutex){+.+.}, at: [<0000000068ee3107>] sock_ioctl+0x367/0x440 net/socket.c:1020 1 lock held by syz-executor0/22280: #0: (br_ioctl_mutex){+.+.}, at: [<0000000068ee3107>] sock_ioctl+0x367/0x440 net/socket.c:1020 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 746 Comm: khungtaskd Not tainted 4.15.0-rc7+ #187 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:53 nmi_cpu_backtrace+0x1d2/0x210 lib/nmi_backtrace.c:103 nmi_trigger_cpumask_backtrace+0x122/0x180 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace include/linux/nmi.h:138 [inline] check_hung_task kernel/hung_task.c:132 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:190 [inline] watchdog+0x90c/0xd60 kernel/hung_task.c:249 kthread+0x33c/0x400 kernel/kthread.c:238 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:524 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.15.0-rc7+ #187 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:atomic_add_return arch/x86/include/asm/atomic.h:157 [inline] RIP: 0010:rcu_dynticks_eqs_exit+0x1d/0x30 kernel/rcu/tree.c:323 RSP: 0018:ffff8801db307d30 EFLAGS: 00000002 RAX: ffff8801db323760 RBX: ffff8801db323760 RCX: 0000000000000000 RDX: 0000000000028800 RSI: 0000000000000001 RDI: ffff8801db323768 RBP: ffff8801db307d30 R08: 1ffff1003b665985 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801d9f66300 R13: 1ffff1003b660fb1 R14: ffff8801db307e68 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000c420009e80 CR3: 0000000006822003 CR4: 00000000001606e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_eqs_exit_common kernel/rcu/tree.c:936 [inline] rcu_irq_enter+0x153/0x190 kernel/rcu/tree.c:1056 irq_enter+0x13/0xd0 kernel/softirq.c:339 scheduler_ipi+0x23d/0x820 kernel/sched/core.c:1793 smp_reschedule_interrupt+0xe6/0x670 arch/x86/kernel/smp.c:277 reschedule_interrupt+0xa9/0xb0 arch/x86/entry/entry_64.S:944 RIP: 0010:native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:54 RSP: 0018:ffff8801d9f77cb0 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff02 RAX: dffffc0000000000 RBX: 1ffff1003b3eef99 RCX: 0000000000000000 RDX: 1ffffffff0d19078 RSI: 0000000000000001 RDI: ffffffff868c83c0 RBP: ffff8801d9f77cb0 R08: ffffffff86677ae8 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 R13: ffff8801d9f77d68 R14: ffffffff8703d260 R15: 0000000000000000 arch_safe_halt arch/x86/include/asm/paravirt.h:93 [inline] default_idle+0xbf/0x460 arch/x86/kernel/process.c:355 arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:346 default_idle_call+0x36/0x90 kernel/sched/idle.c:98 cpuidle_idle_call kernel/sched/idle.c:156 [inline] do_idle+0x24a/0x3b0 kernel/sched/idle.c:246 cpu_startup_entry+0x104/0x120 kernel/sched/idle.c:351 start_secondary+0x40a/0x590 arch/x86/kernel/smpboot.c:268 secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:237 Code: ff 90 90 90 90 90 90 90 90 90 90 90 90 90 55 48 c7 c0 60 37 02 00 48 89 e5 65 48 03 05 a5 94 a4 7e ba 02 00 00 00 f0 0f c1 50 0c <83> e2 01 74 05 f0 83 60 0c fe 5d c3 0f 1f 80 00 00 00 00 55 48