INFO: rcu_sched self-detected stall on CPU
INFO: rcu_sched detected stalls on CPUs/tasks:
	0-....: (125000 ticks this GP) idle=b86/1/4611686018427387906 softirq=13091/13091 fqs=31238 
	(detected by 1, t=125002 jiffies, g=6609, c=6608, q=511)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 5933 Comm: syz-executor1 Not tainted 4.15.0-rc6-next-20180103+ #87
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:inb arch/x86/include/asm/io.h:348 [inline]
RIP: 0010:io_serial_in+0x6b/0x90 drivers/tty/serial/8250/8250_port.c:434
RSP: 0018:ffff8801db4078d0 EFLAGS: 00000002
RAX: dffffc0000000000 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: 0000000000000005 RDI: ffffffff87e4ffd8
RBP: ffff8801db4078e0 R08: ffffffff825476b5 R09: 000000000000000c
R10: ffff8801db4078f8 R11: 0000000000000001 R12: ffffffff87e4ffa0
R13: 0000000000000020 R14: fffffbfff0fca039 R15: fffffbfff0fc9ffd
FS:  00007f5da4de7700(0000) GS:ffff8801db400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020012001 CR3: 00000001c012a003 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 serial_in drivers/tty/serial/8250/8250.h:111 [inline]
 wait_for_xmitr+0x93/0x1e0 drivers/tty/serial/8250/8250_port.c:2033
 serial8250_console_putchar+0x1f/0x60 drivers/tty/serial/8250/8250_port.c:3170
 uart_console_write+0xac/0xe0 drivers/tty/serial/serial_core.c:1858
 serial8250_console_write+0x5b3/0x940 drivers/tty/serial/8250/8250_port.c:3236
 univ8250_console_write+0x5f/0x70 drivers/tty/serial/8250/8250_core.c:590
 call_console_drivers kernel/printk/printk.c:1574 [inline]
 console_unlock+0x6ba/0xc30 kernel/printk/printk.c:2233
 vprintk_emit+0x4ad/0x590 kernel/printk/printk.c:1757
 vprintk_default+0x28/0x30 kernel/printk/printk.c:1796
 vprintk_func+0x57/0xc0 kernel/printk/printk_safe.c:379
 printk+0xaa/0xca kernel/printk/printk.c:1829
 print_cpu_stall_info_begin kernel/rcu/tree_plugin.h:1686 [inline]
 print_cpu_stall kernel/rcu/tree.c:1510 [inline]
 check_cpu_stall kernel/rcu/tree.c:1592 [inline]
 __rcu_pending kernel/rcu/tree.c:3362 [inline]
 rcu_pending kernel/rcu/tree.c:3424 [inline]
 rcu_check_callbacks+0xb68/0x1de0 kernel/rcu/tree.c:2764
 update_process_times+0x30/0x60 kernel/time/timer.c:1628
 tick_sched_handle+0x85/0x160 kernel/time/tick-sched.c:162
 tick_sched_timer+0x42/0x120 kernel/time/tick-sched.c:1176
 __run_hrtimer kernel/time/hrtimer.c:1210 [inline]
 __hrtimer_run_queues+0x2c8/0xb50 kernel/time/hrtimer.c:1274
 hrtimer_interrupt+0x1c2/0x5e0 kernel/time/hrtimer.c:1308
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1025 [inline]
 smp_apic_timer_interrupt+0xc9/0x4c0 arch/x86/kernel/apic/apic.c:1050
 apic_timer_interrupt+0xa9/0xb0 arch/x86/entry/entry_64.S:920
 </IRQ>
RIP: 0010:arch_local_irq_enable arch/x86/include/asm/paravirt.h:787 [inline]
RIP: 0010:snd_pcm_stream_unlock_irq+0xac/0xe0 sound/core/pcm_native.c:166
RSP: 0018:ffff8801c3f277e8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff11
RAX: 0000000000010000 RBX: ffff8801d3846300 RCX: ffffffff83b29145
RDX: 0000000000010000 RSI: ffffc90002113000 RDI: ffffffff85ec84f8
RBP: ffff8801c3f277f0 R08: ffffffff864672d8 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 00000000000046ee
R13: dffffc0000000000 R14: 0000000000000001 R15: ffff8801c0500200
 __snd_pcm_lib_xfer+0xe0b/0x1880 sound/core/pcm_lib.c:2219
 snd_pcm_oss_write3+0xe2/0x1b0 sound/core/oss/pcm_oss.c:1181
 io_playback_transfer+0x204/0x2b0 sound/core/oss/io.c:47
 snd_pcm_plug_write_transfer+0x2a0/0x390 sound/core/oss/pcm_plugin.c:611
 snd_pcm_oss_write2+0x22e/0x3c0 sound/core/oss/pcm_oss.c:1310
 snd_pcm_oss_write1 sound/core/oss/pcm_oss.c:1371 [inline]
 snd_pcm_oss_write+0x4c1/0x690 sound/core/oss/pcm_oss.c:2645
 __vfs_write+0xef/0x740 fs/read_write.c:480
 vfs_write+0x189/0x510 fs/read_write.c:544
 SYSC_write fs/read_write.c:589 [inline]
 SyS_write+0xd4/0x1a0 fs/read_write.c:581
 entry_SYSCALL_64_fastpath+0x23/0x9a
RIP: 0033:0x452ac9
RSP: 002b:00007f5da4de6c58 EFLAGS: 00000212 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000000000071bea0 RCX: 0000000000452ac9
RDX: 00000000fffffee4 RSI: 0000000020735ee0 RDI: 0000000000000014
RBP: 00000000000003c7 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006f3b48
R13: 00000000ffffffff R14: 00007f5da4de76d4 R15: 0000000000000000
Code: 24 d1 00 00 00 49 8d 7c 24 38 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 d3 e3 80 3c 02 00 75 17 41 03 5c 24 38 89 da ec <5b> 0f b6 c0 41 5c 5d c3 e8 48 56 36 ff eb c2 e8 a1 56 36 ff eb 
	0-....: (125000 ticks this GP) idle=b86/1/4611686018427387906 softirq=13091/13091 fqs=31375 
	 (t=125558 jiffies g=6609 c=6608 q=511)
NMI backtrace for cpu 0
CPU: 0 PID: 5933 Comm: syz-executor1 Not tainted 4.15.0-rc6-next-20180103+ #87
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+0x137/0x198 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+0x186/0x1d7 kernel/rcu/tree.c:1375
 print_cpu_stall kernel/rcu/tree.c:1524 [inline]
 check_cpu_stall kernel/rcu/tree.c:1592 [inline]
 __rcu_pending kernel/rcu/tree.c:3362 [inline]
 rcu_pending kernel/rcu/tree.c:3424 [inline]
 rcu_check_callbacks+0x1a64/0x1de0 kernel/rcu/tree.c:2764
 update_process_times+0x30/0x60 kernel/time/timer.c:1628
 tick_sched_handle+0x85/0x160 kernel/time/tick-sched.c:162
 tick_sched_timer+0x42/0x120 kernel/time/tick-sched.c:1176
 __run_hrtimer kernel/time/hrtimer.c:1210 [inline]
 __hrtimer_run_queues+0x2c8/0xb50 kernel/time/hrtimer.c:1274
 hrtimer_interrupt+0x1c2/0x5e0 kernel/time/hrtimer.c:1308
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1025 [inline]
 smp_apic_timer_interrupt+0xc9/0x4c0 arch/x86/kernel/apic/apic.c:1050
 apic_timer_interrupt+0xa9/0xb0 arch/x86/entry/entry_64.S:920
 </IRQ>
RIP: 0010:arch_local_irq_enable arch/x86/include/asm/paravirt.h:787 [inline]
RIP: 0010:snd_pcm_stream_unlock_irq+0xac/0xe0 sound/core/pcm_native.c:166
RSP: 0018:ffff8801c3f277e8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff11
RAX: 0000000000010000 RBX: ffff8801d3846300 RCX: ffffffff83b29145
RDX: 0000000000010000 RSI: ffffc90002113000 RDI: ffffffff85ec84f8
RBP: ffff8801c3f277f0 R08: ffffffff864672d8 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 00000000000046ee
R13: dffffc0000000000 R14: 0000000000000001 R15: ffff8801c0500200
 __snd_pcm_lib_xfer+0xe0b/0x1880 sound/core/pcm_lib.c:2219
 snd_pcm_oss_write3+0xe2/0x1b0 sound/core/oss/pcm_oss.c:1181
 io_playback_transfer+0x204/0x2b0 sound/core/oss/io.c:47
 snd_pcm_plug_write_transfer+0x2a0/0x390 sound/core/oss/pcm_plugin.c:611
 snd_pcm_oss_write2+0x22e/0x3c0 sound/core/oss/pcm_oss.c:1310
 snd_pcm_oss_write1 sound/core/oss/pcm_oss.c:1371 [inline]
 snd_pcm_oss_write+0x4c1/0x690 sound/core/oss/pcm_oss.c:2645
 __vfs_write+0xef/0x740 fs/read_write.c:480
 vfs_write+0x189/0x510 fs/read_write.c:544
 SYSC_write fs/read_write.c:589 [inline]
 SyS_write+0xd4/0x1a0 fs/read_write.c:581
 entry_SYSCALL_64_fastpath+0x23/0x9a
RIP: 0033:0x452ac9
RSP: 002b:00007f5da4de6c58 EFLAGS: 00000212 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000000000071bea0 RCX: 0000000000452ac9
RDX: 00000000fffffee4 RSI: 0000000020735ee0 RDI: 0000000000000014
RBP: 00000000000003c7 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006f3b48
R13: 00000000ffffffff R14: 00007f5da4de76d4 R15: 0000000000000000