Buffer I/O error on dev loop0, logical block 15, async page read
INFO: task syz-executor7:29658 blocked for more than 120 seconds.
      Not tainted 4.4.128-gbd23e3a #19
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor7   D ffff8801bc24f250 26736 29658   3921 0x20020004
 ffff8801bc24f250 ffff8800a148e8e0 0000000000000025 ffffffff844bdc20
 0000000000000000 ffff8801db21fdb8 ffff8801db21fde0 ffff8801db21f4d8
 ffff8801db21f4c0 ffffffff84417840 ffff8800a148e000 ffff8801bc24f7f0
Call Trace:
 [<ffffffff838b074a>] schedule+0x7a/0x1b0 kernel/sched/core.c:3359
 [<ffffffff838bbb61>] schedule_timeout+0x481/0x8b0 kernel/time/timer.c:1515
 [<ffffffff838ae60a>] io_schedule_timeout+0x1ba/0x390 kernel/sched/core.c:4941
 [<ffffffff838b199b>] io_schedule include/linux/sched.h:447 [inline]
 [<ffffffff838b199b>] bit_wait_io+0x1b/0xd0 kernel/sched/wait.c:595
 [<ffffffff838b112d>] __wait_on_bit+0xbd/0x140 kernel/sched/wait.c:395
 [<ffffffff8141c247>] wait_on_page_bit+0x1d7/0x200 mm/filemap.c:758
 [<ffffffff8141c433>] wait_on_page_writeback include/linux/pagemap.h:530 [inline]
 [<ffffffff8141c433>] __filemap_fdatawait_range+0x1c3/0x2c0 mm/filemap.c:410
 [<ffffffff8141c555>] filemap_fdatawait_range+0x25/0x50 mm/filemap.c:440
 [<ffffffff81422795>] filemap_write_and_wait_range+0x85/0xb0 mm/filemap.c:539
 [<ffffffff815cfda6>] blkdev_fsync+0x66/0xb0 fs/block_dev.c:355
 [<ffffffff815bca3c>] vfs_fsync_range+0x10c/0x260 fs/sync.c:195
 [<ffffffff815d317c>] generic_write_sync include/linux/fs.h:2515 [inline]
 [<ffffffff815d317c>] blkdev_write_iter+0x38c/0x470 fs/block_dev.c:1658
 [<ffffffff8151bcac>] vfs_iter_write+0x1cc/0x2d0 fs/read_write.c:364
 [<ffffffff815b7cf2>] iter_file_splice_write+0x622/0xb90 fs/splice.c:1024
 [<ffffffff815b4848>] do_splice_from fs/splice.c:1128 [inline]
 [<ffffffff815b4848>] direct_splice_actor+0x128/0x190 fs/splice.c:1294
 [<ffffffff815b58f7>] splice_direct_to_actor+0x2c7/0x830 fs/splice.c:1247
 [<ffffffff815b6003>] do_splice_direct+0x1a3/0x270 fs/splice.c:1337
 [<ffffffff8151fd54>] do_sendfile+0x4e4/0xb80 fs/read_write.c:1227
 [<ffffffff81521ea1>] C_SYSC_sendfile fs/read_write.c:1303 [inline]
 [<ffffffff81521ea1>] 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
 [<ffffffff838c00aa>] sysenter_flags_fixed+0xd/0x17
no locks held by syz-executor7/29658.
Sending NMI to all CPUs:
NMI backtrace for cpu 0
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.128-gbd23e3a #19
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffffffff84417840 task.stack: ffffffff84400000
RIP: 0010:[<ffffffff8122e2ae>]  [<ffffffff8122e2ae>] mark_held_locks+0xee/0x130 kernel/locking/lockdep.c:2541
RSP: 0018:ffffffff84407c78  EFLAGS: 00000092
RAX: 0000000000000001 RBX: ffffffff84417840 RCX: 0000000000000000
RDX: 1ffffffff0883023 RSI: 0000000000000001 RDI: ffffffff84417840
RBP: ffffffff84407c98 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff838bf369
R13: 0000000000000000 R14: ffffffff84417840 R15: ffffffff84a05868
FS:  0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000cb7000 CR3: 00000001ca894000 CR4: 0000000000160670
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff838bf369 0000000000000000 fffffbfff074890c ffffffff84a05868
 ffffffff84407cb8 ffffffff8122e67b ffffffff84a05868 0000000000000000
 ffffffff84407dc8 ffffffff81003017 0000000000000000 0000000000000000
Call Trace:
 [<ffffffff8122e67b>] __trace_hardirqs_on_caller kernel/locking/lockdep.c:2565 [inline]
 [<ffffffff8122e67b>] trace_hardirqs_on_caller+0x38b/0x590 kernel/locking/lockdep.c:2612
 [<ffffffff81003017>] trace_hardirqs_on_thunk+0x17/0x19
 [<ffffffff81025da5>] arch_safe_halt arch/x86/include/asm/paravirt.h:117 [inline]
 [<ffffffff81025da5>] default_idle+0x55/0x3c0 arch/x86/kernel/process.c:290
 [<ffffffff810272f0>] arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:281
 [<ffffffff8121b9c7>] default_idle_call+0x57/0x70 kernel/sched/idle.c:93
 [<ffffffff8121c16f>] cpuidle_idle_call kernel/sched/idle.c:157 [inline]
 [<ffffffff8121c16f>] cpu_idle_loop kernel/sched/idle.c:253 [inline]
 [<ffffffff8121c16f>] cpu_startup_entry+0x6af/0x780 kernel/sched/idle.c:301
 [<ffffffff838ab8b1>] rest_init+0x188/0x18e init/main.c:410
 [<ffffffff84a4b8a1>] start_kernel+0x6b3/0x6e7 init/main.c:682
 [<ffffffff84a4a30f>] x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:196
 [<ffffffff84a4a450>] x86_64_start_kernel+0x13f/0x162 arch/x86/kernel/head64.c:185
Code: b9 ec ff ff 85 c0 74 1e 41 0f b6 45 00 83 c3 01 84 c0 74 04 3c 03 7e 40 41 39 9e d8 08 00 00 7f a1 b8 01 00 00 00 48 83 c4 18 5b <41> 5c 41 5d 41 5e 41 5f 5d c3 48 8b 7d c8 89 75 d4 e8 cc ab 2c 
NMI backtrace for cpu 1
CPU: 1 PID: 491 Comm: khungtaskd Not tainted 4.4.128-gbd23e3a #19
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801d8f66000 task.stack: ffff8801d8f78000
RIP: 0010:[<ffffffff810bfd66>]  [<ffffffff810bfd66>] native_apic_mem_write arch/x86/include/asm/apic.h:94 [inline]
RIP: 0010:[<ffffffff810bfd66>]  [<ffffffff810bfd66>] __default_send_IPI_dest_field arch/x86/include/asm/ipi.h:119 [inline]
RIP: 0010:[<ffffffff810bfd66>]  [<ffffffff810bfd66>] _flat_send_IPI_mask arch/x86/kernel/apic/apic_flat_64.c:61 [inline]
RIP: 0010:[<ffffffff810bfd66>]  [<ffffffff810bfd66>] flat_send_IPI_mask+0xf6/0x1a0 arch/x86/kernel/apic/apic_flat_64.c:69
RSP: 0018:ffff8801d8f7fcc8  EFLAGS: 00000046
RAX: 0000000003000000 RBX: 0000000000000c00 RCX: 0000000000000000
RDX: 0000000000000c00 RSI: 0000000000000000 RDI: ffffffffff5fb300
RBP: ffff8801d8f7fcf0 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: 00007f32786d6000 CR3: 00000001ca894000 CR4: 0000000000160670
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff8446f7a0 ffffffff84a187a0 0000000000000007 fffffbfff0942ba4
 0000000000000040 ffff8801d8f7fd10 ffffffff810b5d21 ffffffff83c0b0e0
 0000000000000003 ffff8801d8f7fd68 ffffffff81e18b43 ffff8800a148e000
Call Trace:
 [<ffffffff810b5d21>] nmi_raise_cpu_backtrace+0x61/0x80 arch/x86/kernel/apic/hw_nmi.c:33
 [<ffffffff81e18b43>] nmi_trigger_all_cpu_backtrace.cold.4+0x70/0xad lib/nmi_backtrace.c:85
 [<ffffffff810b5dc4>] arch_trigger_all_cpu_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 [<ffffffff8141a189>] trigger_all_cpu_backtrace include/linux/nmi.h:44 [inline]
 [<ffffffff8141a189>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff8141a189>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff8141a189>] watchdog.cold.1+0xd3/0xee kernel/hung_task.c:238
 [<ffffffff81190748>] kthread+0x268/0x300 kernel/kthread.c:211
 [<ffffffff838beb95>] 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 82