INFO: task syz-executor0:16380 blocked for more than 120 seconds.
      Not tainted 4.4.136-ge4798d7 #58
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor0   D ffff8800af3c7460 26360 16380   3815 0x20020004
 ffff8800af3c7460 000000000000003f ffffea00026edd40 cdc76b334e50f3fd
 ffff8800af3c7600 ffff8801db31fdb8 ffff8801db31fde0 ffff8801db31f4d8
 ffff8801db31f4c0 ffff8801bb34b000 ffff8801ccf21800 0000000000000000
Call Trace:
 [<ffffffff838b47fa>] schedule+0x7a/0x1b0 kernel/sched/core.c:3359
 [<ffffffff838bfc11>] schedule_timeout+0x481/0x8b0 kernel/time/timer.c:1515
 [<ffffffff838b26ba>] io_schedule_timeout+0x1ba/0x390 kernel/sched/core.c:4941
 [<ffffffff838b5a4b>] io_schedule include/linux/sched.h:447 [inline]
 [<ffffffff838b5a4b>] bit_wait_io+0x1b/0xd0 kernel/sched/wait.c:595
 [<ffffffff838b55b2>] __wait_on_bit_lock.part.4+0x92/0x140 kernel/sched/wait.c:434
 [<ffffffff838b5669>] __wait_on_bit_lock+0x9/0x10 kernel/sched/wait.c:427
 [<ffffffff8141cdfd>] __lock_page+0x17d/0x1f0 mm/filemap.c:888
 [<ffffffff815b9aab>] lock_page include/linux/pagemap.h:458 [inline]
 [<ffffffff815b9aab>] __generic_file_splice_read+0x7eb/0xbb0 fs/splice.c:412
 [<ffffffff815b9f52>] generic_file_splice_read+0xe2/0x1c0 fs/splice.c:542
 [<ffffffff815b60a7>] do_splice_to+0xf7/0x140 fs/splice.c:1154
 [<ffffffff815b6332>] splice_direct_to_actor+0x242/0x830 fs/splice.c:1226
 [<ffffffff815b6ac3>] do_splice_direct+0x1a3/0x270 fs/splice.c:1337
 [<ffffffff81520664>] do_sendfile+0x4e4/0xb80 fs/read_write.c:1227
 [<ffffffff815227b1>] C_SYSC_sendfile fs/read_write.c:1303 [inline]
 [<ffffffff815227b1>] compat_SyS_sendfile+0xd1/0x160 fs/read_write.c:1292
 [<ffffffff81006d96>] do_syscall_32_irqs_on arch/x86/entry/common.c:392 [inline]
 [<ffffffff81006d96>] do_fast_syscall_32+0x326/0x8b0 arch/x86/entry/common.c:459
 [<ffffffff838c416a>] sysenter_flags_fixed+0xd/0x17
no locks held by syz-executor0/16380.
Sending NMI to all CPUs:
NMI backtrace for cpu 0
CPU: 0 PID: 16481 Comm: init Not tainted 4.4.136-ge4798d7 #58
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8800b01e3000 task.stack: ffff88009cd70000
RIP: 0010:[<ffffffff81e3b753>]  [<ffffffff81e3b753>] rep_nop arch/x86/include/asm/processor.h:562 [inline]
RIP: 0010:[<ffffffff81e3b753>]  [<ffffffff81e3b753>] delay_tsc+0x33/0xc0 arch/x86/lib/delay.c:66
RSP: 0018:ffff88009cd77500  EFLAGS: 00000082
RAX: 0000000080000001 RBX: 00000103b2ac8523 RCX: 0000000000000000
RDX: 0000000000000002 RSI: ffffffff81e6e93b RDI: ffffffff8592e640
RBP: ffff88009cd77520 R08: ffffffff8538f260 R09: 0000000000000000
R10: 0000000000000001 R11: ffff8800b01e3000 R12: 00000103b2ac8359
R13: 00000000000008fd R14: 0000000000000000 R15: fffffbfff0c554a1
FS:  00007f4a613e87a0(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4a60afba30 CR3: 00000000b26c9000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff862aa4c0 0000000000002702 0000000000000020 fffffbfff0c554df
 ffff88009cd77530 ffffffff81e3b691 ffff88009cd77580 ffffffff82085b1f
 0000000000000046 ffffffff862aa508 ffffffff862aa6fa ffffffff862aa4c0
Call Trace:
 [<ffffffff81e3b691>] __delay arch/x86/lib/delay.c:160 [inline]
 [<ffffffff81e3b691>] __const_udelay+0x31/0x40 arch/x86/lib/delay.c:174
 [<ffffffff82085b1f>] wait_for_xmitr+0x6f/0x1e0 drivers/tty/serial/8250/8250_port.c:1725
 [<ffffffff82085caf>] serial8250_console_putchar+0x1f/0x60 drivers/tty/serial/8250/8250_port.c:2806
 [<ffffffff82070149>] uart_console_write+0x59/0xf0 drivers/tty/serial/serial_core.c:1789
 [<ffffffff82090309>] serial8250_console_write+0x539/0x830 drivers/tty/serial/8250/8250_port.c:2872
 [<ffffffff8207ecef>] univ8250_console_write+0x5f/0x70 drivers/tty/serial/8250/8250_core.c:594
 [<ffffffff81259f1f>] call_console_drivers.constprop.28+0x1ef/0x3f0 kernel/printk/printk.c:1463
 [<ffffffff8125cbf5>] console_unlock+0x605/0xa10 kernel/printk/printk.c:2330
 [<ffffffff8125dd07>] console_device+0x97/0xc0 kernel/printk/printk.c:2438
 [<ffffffff8204d05f>] tty_lookup_driver drivers/tty/tty_io.c:2000 [inline]
 [<ffffffff8204d05f>] tty_open+0x8bf/0xf00 drivers/tty/tty_io.c:2068
 [<ffffffff8152964d>] chrdev_open+0x22d/0x4c0 fs/char_dev.c:388
 [<ffffffff81517acb>] do_dentry_open+0x68b/0xbc0 fs/open.c:749
 [<ffffffff8151b0fa>] vfs_open+0x12a/0x210 fs/open.c:862
 [<ffffffff8154c19e>] do_last fs/namei.c:3222 [inline]
 [<ffffffff8154c19e>] path_openat+0x4ee/0x3a10 fs/namei.c:3359
 [<ffffffff815523d7>] do_filp_open+0x197/0x270 fs/namei.c:3393
 [<ffffffff8151ba1c>] do_sys_open+0x31c/0x610 fs/open.c:1038
 [<ffffffff8151bd3d>] SYSC_open fs/open.c:1056 [inline]
 [<ffffffff8151bd3d>] SyS_open+0x2d/0x40 fs/open.c:1051
 [<ffffffff838c2825>] entry_SYSCALL_64_fastpath+0x22/0x9e
Code: 49 89 fd bf 01 00 00 00 41 54 53 e8 78 a7 36 ff e8 33 33 03 00 41 89 c6 0f ae e8 0f 31 48 c1 e2 20 48 09 c2 49 89 d4 eb 16 f3 90 <bf> 01 00 00 00 e8 53 a7 36 ff e8 0e 33 03 00 44 39 f0 75 36 0f 
NMI backtrace for cpu 1
CPU: 1 PID: 492 Comm: khungtaskd Not tainted 4.4.136-ge4798d7 #58
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801d8eae000 task.stack: ffff8800bb350000
RIP: 0010:[<ffffffff810bfeb6>]  [<ffffffff810bfeb6>] native_apic_mem_write arch/x86/include/asm/apic.h:94 [inline]
RIP: 0010:[<ffffffff810bfeb6>]  [<ffffffff810bfeb6>] __default_send_IPI_dest_field arch/x86/include/asm/ipi.h:119 [inline]
RIP: 0010:[<ffffffff810bfeb6>]  [<ffffffff810bfeb6>] _flat_send_IPI_mask arch/x86/kernel/apic/apic_flat_64.c:61 [inline]
RIP: 0010:[<ffffffff810bfeb6>]  [<ffffffff810bfeb6>] flat_send_IPI_mask+0xf6/0x1a0 arch/x86/kernel/apic/apic_flat_64.c:69
RSP: 0018:ffff8800bb357cc8  EFLAGS: 00000046
RAX: 0000000003000000 RBX: 0000000000000c00 RCX: 0000000000000000
RDX: 0000000000000c00 RSI: 0000000000000000 RDI: ffffffffff5fb300
RBP: ffff8800bb357cf0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000246
R13: 0000000000000003 R14: 0000000000000002 R15: ffffffff8446f7a0
FS:  0000000000000000(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000001750b10 CR3: 00000000b33c0000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff8446f7a0 ffffffff84a18ea0 0000000000000007 fffffbfff0942c84
 0000000000000040 ffff8800bb357d10 ffffffff810b5e71 ffffffff83c0b560
 0000000000000003 ffff8800bb357d68 ffffffff81e19e23 ffff8801ccf21800
Call Trace:
 [<ffffffff810b5e71>] nmi_raise_cpu_backtrace+0x61/0x80 arch/x86/kernel/apic/hw_nmi.c:33
 [<ffffffff81e19e23>] nmi_trigger_all_cpu_backtrace.cold.4+0x70/0xad lib/nmi_backtrace.c:85
 [<ffffffff810b5f14>] arch_trigger_all_cpu_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 [<ffffffff8141a459>] trigger_all_cpu_backtrace include/linux/nmi.h:44 [inline]
 [<ffffffff8141a459>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff8141a459>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff8141a459>] watchdog.cold.1+0xd3/0xee kernel/hung_task.c:238
 [<ffffffff81190958>] kthread+0x268/0x300 kernel/kthread.c:211
 [<ffffffff838c2c55>] ret_from_fork+0x55/0x80 arch/x86/entry/entry_64.S:510
Code: b3 5f ff f6 c4 10 75 e2 44 89 e8 c1 e0 18 89 04 25 10 b3 5f ff 44 89 f2 09 da 80 cf 04 41 83 fe 02 0f 44 d3 89 14 25 00 b3 5f ff <41> f7 c4 00 02 00 00 75 1a 4c 89 e7 57 9d 0f 1f 44 00 00 e8 72