INFO: task syz-executor0:23913 blocked for more than 120 seconds.
      Not tainted 4.4.132-g1a2b3e7 #43
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor0   D ffff8800a318f460 26360 23913   3905 0x20020004
 ffff8800a318f460 0000000000000040 00000000f57a80ac 21840740f3c483d3
 ffff8800a318f600 ffff8801db21fdb8 ffff8801db21fde0 ffff8801db21f4d8
 ffff8801db21f4c0 ffff8800b97e1800 ffff8801c929e000 0000000000000000
Call Trace:
 [<ffffffff838b220a>] schedule+0x7a/0x1b0 kernel/sched/core.c:3359
 [<ffffffff838bd621>] schedule_timeout+0x481/0x8b0 kernel/time/timer.c:1515
 [<ffffffff838b00ca>] io_schedule_timeout+0x1ba/0x390 kernel/sched/core.c:4941
 [<ffffffff838b345b>] io_schedule include/linux/sched.h:447 [inline]
 [<ffffffff838b345b>] bit_wait_io+0x1b/0xd0 kernel/sched/wait.c:595
 [<ffffffff838b2fc2>] __wait_on_bit_lock.part.4+0x92/0x140 kernel/sched/wait.c:434
 [<ffffffff838b3079>] __wait_on_bit_lock+0x9/0x10 kernel/sched/wait.c:427
 [<ffffffff8141ca5d>] __lock_page+0x17d/0x1f0 mm/filemap.c:888
 [<ffffffff815b915b>] lock_page include/linux/pagemap.h:458 [inline]
 [<ffffffff815b915b>] __generic_file_splice_read+0x7eb/0xbb0 fs/splice.c:412
 [<ffffffff815b9602>] generic_file_splice_read+0xe2/0x1c0 fs/splice.c:542
 [<ffffffff815b5757>] do_splice_to+0xf7/0x140 fs/splice.c:1154
 [<ffffffff815b59e2>] splice_direct_to_actor+0x242/0x830 fs/splice.c:1226
 [<ffffffff815b6173>] do_splice_direct+0x1a3/0x270 fs/splice.c:1337
 [<ffffffff8151ff14>] do_sendfile+0x4e4/0xb80 fs/read_write.c:1227
 [<ffffffff81522061>] C_SYSC_sendfile fs/read_write.c:1303 [inline]
 [<ffffffff81522061>] 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
 [<ffffffff838c1b6a>] sysenter_flags_fixed+0xd/0x17
no locks held by syz-executor0/23913.
Sending NMI to all CPUs:
NMI backtrace for cpu 0
CPU: 0 PID: 492 Comm: khungtaskd Not tainted 4.4.132-g1a2b3e7 #43
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8800bacc9800 task.stack: ffff8801d8d78000
RIP: 0010:[<ffffffff810bfe16>]  [<ffffffff810bfe16>] native_apic_mem_write arch/x86/include/asm/apic.h:94 [inline]
RIP: 0010:[<ffffffff810bfe16>]  [<ffffffff810bfe16>] __default_send_IPI_dest_field arch/x86/include/asm/ipi.h:119 [inline]
RIP: 0010:[<ffffffff810bfe16>]  [<ffffffff810bfe16>] _flat_send_IPI_mask arch/x86/kernel/apic/apic_flat_64.c:61 [inline]
RIP: 0010:[<ffffffff810bfe16>]  [<ffffffff810bfe16>] flat_send_IPI_mask+0xf6/0x1a0 arch/x86/kernel/apic/apic_flat_64.c:69
RSP: 0018:ffff8801d8d7fcc8  EFLAGS: 00000046
RAX: 0000000003000000 RBX: 0000000000000c00 RCX: 0000000000000000
RDX: 0000000000000c00 RSI: 0000000000000000 RDI: ffffffffff5fb300
RBP: ffff8801d8d7fcf0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000246
R13: 0000000000000003 R14: 0000000000000002 R15: ffffffff8446f7a0
FS:  0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000007a1b10 CR3: 00000001cba7e000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff8446f7a0 ffffffff84a18a60 0000000000000007 fffffbfff0942bfc
 0000000000000040 ffff8801d8d7fd10 ffffffff810b5dd1 ffffffff83c0b1a0
 0000000000000003 ffff8801d8d7fd68 ffffffff81e19003 ffff8801c929e000
Call Trace:
 [<ffffffff810b5dd1>] nmi_raise_cpu_backtrace+0x61/0x80 arch/x86/kernel/apic/hw_nmi.c:33
 [<ffffffff81e19003>] nmi_trigger_all_cpu_backtrace.cold.4+0x70/0xad lib/nmi_backtrace.c:85
 [<ffffffff810b5e74>] arch_trigger_all_cpu_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 [<ffffffff8141a0b9>] trigger_all_cpu_backtrace include/linux/nmi.h:44 [inline]
 [<ffffffff8141a0b9>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff8141a0b9>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff8141a0b9>] watchdog.cold.1+0xd3/0xee kernel/hung_task.c:238
 [<ffffffff81190768>] kthread+0x268/0x300 kernel/kthread.c:211
 [<ffffffff838c0655>] 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 f2 
NMI backtrace for cpu 1
CPU: 1 PID: 23979 Comm: init Not tainted 4.4.132-g1a2b3e7 #43
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8800bb9dc800 task.stack: ffff8801af4b8000
RIP: 0010:[<ffffffff820830db>]  [<ffffffff820830db>] inb arch/x86/include/asm/io.h:316 [inline]
RIP: 0010:[<ffffffff820830db>]  [<ffffffff820830db>] io_serial_in+0x6b/0x90 drivers/tty/serial/8250/8250_port.c:398
RSP: 0018:ffff8801af4bf520  EFLAGS: 00000002
RAX: dffffc0000000000 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: ffffffff82083081 RDI: ffffffff862aa4f8
RBP: ffff8801af4bf530 R08: ffffffff8538f260 R09: 0000000000000000
R10: 0000000000000001 R11: ffff8800bb9dc800 R12: ffffffff862aa4c0
R13: 0000000000000020 R14: fffffbfff0c554df R15: fffffbfff0c554a1
FS:  00007f67dad3d7a0(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f67da450a30 CR3: 00000001ccc01000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff862aa4c0 000000000000270b ffff8801af4bf580 ffffffff82084c3f
 0000000000000046 ffffffff862aa508 ffffffff862aa6fa ffffffff862aa4c0
 0000000000000034 ffffffff82084d90 dffffc0000000000 0000000000000034
Call Trace:
 [<ffffffff82084c3f>] serial_in drivers/tty/serial/8250/8250.h:97 [inline]
 [<ffffffff82084c3f>] wait_for_xmitr+0x8f/0x1e0 drivers/tty/serial/8250/8250_port.c:1717
 [<ffffffff82084daf>] serial8250_console_putchar+0x1f/0x60 drivers/tty/serial/8250/8250_port.c:2806
 [<ffffffff8206f249>] uart_console_write+0x59/0xf0 drivers/tty/serial/serial_core.c:1789
 [<ffffffff8208f409>] serial8250_console_write+0x539/0x830 drivers/tty/serial/8250/8250_port.c:2872
 [<ffffffff8207ddef>] univ8250_console_write+0x5f/0x70 drivers/tty/serial/8250/8250_core.c:594
 [<ffffffff81259cff>] call_console_drivers.constprop.28+0x1ef/0x3f0 kernel/printk/printk.c:1463
 [<ffffffff8125c9d5>] console_unlock+0x605/0xa10 kernel/printk/printk.c:2330
 [<ffffffff8125dae7>] console_device+0x97/0xc0 kernel/printk/printk.c:2438
 [<ffffffff8204c15f>] tty_lookup_driver drivers/tty/tty_io.c:2000 [inline]
 [<ffffffff8204c15f>] tty_open+0x8bf/0xf00 drivers/tty/tty_io.c:2068
 [<ffffffff81528efd>] chrdev_open+0x22d/0x4c0 fs/char_dev.c:388
 [<ffffffff8151737b>] do_dentry_open+0x68b/0xbc0 fs/open.c:749
 [<ffffffff8151a9aa>] vfs_open+0x12a/0x210 fs/open.c:862
 [<ffffffff8154b9ce>] do_last fs/namei.c:3222 [inline]
 [<ffffffff8154b9ce>] path_openat+0x4ee/0x3a10 fs/namei.c:3359
 [<ffffffff81551c07>] do_filp_open+0x197/0x270 fs/namei.c:3393
 [<ffffffff8151b2cc>] do_sys_open+0x31c/0x610 fs/open.c:1038
 [<ffffffff8151b5ed>] SYSC_open fs/open.c:1056 [inline]
 [<ffffffff8151b5ed>] SyS_open+0x2d/0x40 fs/open.c:1051
 [<ffffffff838c0225>] entry_SYSCALL_64_fastpath+0x22/0x9e
Code: 24 c1 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 28 5f 47 ff eb c2 e8 81 5f 47 ff eb