øÿÿÿ: renamed from lo
INFO: rcu_sched self-detected stall on CPU
	0-....: (124999 ticks this GP) idle=b06/1/4611686018427387906 softirq=34810/34810 fqs=31224 
	 (t=125000 jiffies g=18895 c=18894 q=871)
NMI backtrace for cpu 0
CPU: 0 PID: 11089 Comm: syz-executor7 Not tainted 4.15.0-rc1-mm1+ #29
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __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_single_cpu_backtrace include/linux/nmi.h:156 [inline]
 rcu_dump_cpu_stacks+0x186/0x1da kernel/rcu/tree.c:1375
 print_cpu_stall kernel/rcu/tree.c:1524 [inline]
 check_cpu_stall.isra.64+0xbb8/0x15b0 kernel/rcu/tree.c:1592
 __rcu_pending kernel/rcu/tree.c:3361 [inline]
 rcu_pending kernel/rcu/tree.c:3423 [inline]
 rcu_check_callbacks+0x238/0xd20 kernel/rcu/tree.c:2763
 update_process_times+0x30/0x60 kernel/time/timer.c:1640
 tick_sched_handle+0x85/0x160 kernel/time/tick-sched.c:162
 tick_sched_timer+0x42/0x120 kernel/time/tick-sched.c:1166
 __run_hrtimer kernel/time/hrtimer.c:1348 [inline]
 __hrtimer_run_queues+0x373/0xea0 kernel/time/hrtimer.c:1411
 hrtimer_interrupt+0x2a5/0x6f0 kernel/time/hrtimer.c:1469
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1025 [inline]
 smp_apic_timer_interrupt+0x14a/0x700 arch/x86/kernel/apic/apic.c:1050
 apic_timer_interrupt+0xa9/0xb0 arch/x86/entry/entry_64.S:907
 </IRQ>
RIP: 0010:variable_test_bit arch/x86/include/asm/bitops.h:332 [inline]
RIP: 0010:inq_canon drivers/tty/n_tty.c:2409 [inline]
RIP: 0010:n_tty_ioctl+0x218/0x2d0 drivers/tty/n_tty.c:2429
RSP: 0018:ffff8801cd9dfb48 EFLAGS: 00000206 ORIG_RAX: ffffffffffffff11
RAX: 0000000000000405 RBX: ffffc900012ea060 RCX: ffffffff8286f03c
RDX: 0000000000010000 RSI: ffffc90001929000 RDI: ffffc900012eb260
RBP: ffff8801cd9dfb88 R08: 0000000000000001 R09: 0000000000000004
R10: 0000000000000000 R11: ffffffff8748cda0 R12: ffffc900012e9000
R13: 000000047d4d6405 R14: 0000000020fdeffc R15: ffff8801c473ebb8
 tty_ioctl+0x32e/0x15f0 drivers/tty/tty_io.c:2638
 vfs_ioctl fs/ioctl.c:46 [inline]
 do_vfs_ioctl+0x1b1/0x1530 fs/ioctl.c:686
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692
 entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x4529d9
RSP: 002b:00007facef9a8c58 EFLAGS: 00000212 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000758020 RCX: 00000000004529d9
RDX: 0000000020fdeffc RSI: 000000000000541b RDI: 0000000000000014
RBP: 00000000000004ac R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006f40c0
R13: 00000000ffffffff R14: 00007facef9a96d4 R15: 0000000000000000
INFO: rcu_sched detected expedited stalls on CPUs/tasks: { 0-... } 127504 jiffies s: 1593 root: 0x1/.
blocking rcu_node structures:
Task dump for CPU 0:
syz-executor7   R  running task    22016 11089   3315 0x0000000c
Call Trace:
 context_switch kernel/sched/core.c:2803 [inline]
 __schedule+0x8f3/0x2060 kernel/sched/core.c:3376
 print_usage_bug+0x3f0/0x3f0 kernel/locking/lockdep.c:2580