unregister_netdevice: waiting for syz1 to become free. Usage count = 4 INFO: task syz-executor1:14468 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-executor1 D26304 14468 4784 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:00007f1bf020dc58 EFLAGS: 00000212 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f1bf020e700 RCX: 0000000000452cf9 RDX: 0000000020fdf000 RSI: 0000000000008940 RDI: 0000000000000015 RBP: 0000000000a2f870 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000212 R12: 0000000000000000 R13: 0000000000a2f7ef R14: 00007f1bf020e9c0 R15: 000000000000000b Showing all locks held in the system: 2 locks held by khungtaskd/746: #0: (rcu_read_lock){....}, at: [<00000000004f38f1>] check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: (rcu_read_lock){....}, at: [<00000000004f38f1>] watchdog+0x1c5/0xd60 kernel/hung_task.c:249 #1: (tasklist_lock){.+.+}, at: [<0000000004c2a2a7>] debug_show_all_locks+0xd3/0x400 kernel/locking/lockdep.c:4464 1 lock held by rsyslogd/3496: #0: (&f->f_pos_lock){+.+.}, at: [<00000000f5032bba>] __fdget_pos+0x12b/0x190 fs/file.c:770 2 locks held by getty/3619: #0: (&tty->ldisc_sem){++++}, at: [<000000008911f10e>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000bde2bb23>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/3620: #0: (&tty->ldisc_sem){++++}, at: [<000000008911f10e>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000bde2bb23>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/3621: #0: (&tty->ldisc_sem){++++}, at: [<000000008911f10e>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000bde2bb23>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/3622: #0: (&tty->ldisc_sem){++++}, at: [<000000008911f10e>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000bde2bb23>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/3623: #0: (&tty->ldisc_sem){++++}, at: [<000000008911f10e>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000bde2bb23>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/3624: #0: (&tty->ldisc_sem){++++}, at: [<000000008911f10e>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000bde2bb23>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/3625: #0: (&tty->ldisc_sem){++++}, at: [<000000008911f10e>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000bde2bb23>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 1 lock held by syz-executor1/14454: #0: (br_ioctl_mutex){+.+.}, at: [<0000000056f8c5e0>] sock_ioctl+0x367/0x440 net/socket.c:1020 1 lock held by syz-executor1/14468: #0: (br_ioctl_mutex){+.+.}, at: [<0000000056f8c5e0>] sock_ioctl+0x367/0x440 net/socket.c:1020 1 lock held by syz-executor1/14473: #0: (br_ioctl_mutex){+.+.}, at: [<0000000056f8c5e0>] sock_ioctl+0x367/0x440 net/socket.c:1020 1 lock held by syz-executor1/14485: #0: (br_ioctl_mutex){+.+.}, at: [<0000000056f8c5e0>] sock_ioctl+0x367/0x440 net/socket.c:1020 1 lock held by syz-executor1/14505: #0: (br_ioctl_mutex){+.+.}, at: [<0000000056f8c5e0>] sock_ioctl+0x367/0x440 net/socket.c:1020 ============================================= NMI backtrace for cpu 1 CPU: 1 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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.15.0-rc7+ #187 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:nr_iowait_cpu+0x0/0x120 kernel/sched/core.c:2886 RSP: 0018:ffff8801db207ce0 EFLAGS: 00000012 RAX: 00000000003a150d RBX: 0000000000000000 RCX: ffffffff8163aa9d RDX: 1ffff1003b644c7d RSI: ffff8801db226360 RDI: 0000000000000000 RBP: ffff8801db207d18 R08: ffff88021fff801c R09: ffff88021fff8008 R10: ffff88021fff8010 R11: ffff88021fff801d R12: 000000399b9c3974 R13: 0000000000000000 R14: ffff8801db2263e8 R15: ffff8801db226360 FS: 0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000041b480 CR3: 0000000006822003 CR4: 00000000001606f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: tick_nohz_stop_idle kernel/time/tick-sched.c:536 [inline] tick_nohz_irq_enter kernel/time/tick-sched.c:1150 [inline] tick_irq_enter+0x262/0x390 kernel/time/tick-sched.c:1169 irq_enter+0xb6/0xd0 kernel/softirq.c:346 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:ffffffff86807c38 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff02 RAX: dffffc0000000000 RBX: 1ffffffff0d00f8a RCX: 0000000000000000 RDX: 1ffffffff0d19078 RSI: 0000000000000001 RDI: ffffffff868c83c0 RBP: ffffffff86807c38 R08: ffffffff86677ae0 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: ffffffff86807cf0 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 rest_init+0xed/0xf0 init/main.c:436 start_kernel+0x7f1/0x819 init/main.c:716 x86_64_start_reservations+0x2a/0x2c arch/x86/kernel/head64.c:378 x86_64_start_kernel+0x77/0x7a arch/x86/kernel/head64.c:359 secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:237 Code: e9 f6 fe ff ff 48 89 85 60 ff ff ff 4c 89 8d 68 ff ff ff e8 a3 d8 5a 00 48 8b 85 60 ff ff ff 4c 8b 8d 68 ff ff ff e9 97 fe ff ff <55> 48 ba 00 00 00 00 00 fc ff df 48 89 e5 41 55 41 54 4c 8d 65