syzbot

INFO: task syz-executor2:19800 blocked for more than 120 seconds.
      Not tainted 4.4.124-g851fb4d #60
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor2   D ffff8800ad0cf270 28072 19800   8791 0x00000004
 ffff8800ad0cf270 0000000000000000 0000000000000000 0000000000000000
 0000000000000000 ffff8801db21fdb8 ffff8801db21fde0 ffff8801db21f4d8
 ffff8801db21f4c0 ffff8800b5069800 ffff8800b0ea8000 ffff8800ad0cf860
Call Trace:
 [<ffffffff8376b59a>] schedule+0x7a/0x1b0 kernel/sched/core.c:3359
 [<ffffffff837768b0>] schedule_timeout+0x3a0/0x970 kernel/time/timer.c:1515
 [<ffffffff8376942e>] io_schedule_timeout+0x1be/0x390 kernel/sched/core.c:4941
 [<ffffffff8376c85b>] io_schedule include/linux/sched.h:447 [inline]
 [<ffffffff8376c85b>] bit_wait_io+0x1b/0xc0 kernel/sched/wait.c:595
 [<ffffffff8376c39f>] __wait_on_bit_lock+0x8f/0x140 kernel/sched/wait.c:434
 [<ffffffff8141e55d>] __lock_page+0x18d/0x1f0 mm/filemap.c:888
 [<ffffffff81421b06>] lock_page include/linux/pagemap.h:458 [inline]
 [<ffffffff81421b06>] pagecache_get_page+0x316/0x3f0 mm/filemap.c:1161
 [<ffffffff81421fc3>] grab_cache_page_write_begin+0x63/0x90 mm/filemap.c:2494
 [<ffffffff815cc00a>] block_write_begin+0x3a/0xd0 fs/buffer.c:2038
 [<ffffffff815d15ec>] blkdev_write_begin+0x3c/0x50 fs/block_dev.c:316
 [<ffffffff8141f4ca>] generic_perform_write+0x28a/0x530 mm/filemap.c:2550
 [<ffffffff81425a4a>] __generic_file_write_iter+0x35a/0x580 mm/filemap.c:2675
 [<ffffffff815d2064>] blkdev_write_iter+0x1d4/0x490 fs/block_dev.c:1655
 [<ffffffff8151d4d7>] vfs_iter_write+0x1c7/0x2d0 fs/read_write.c:364
 [<ffffffff815b8eaa>] iter_file_splice_write+0x58a/0xae0 fs/splice.c:1024
 [<ffffffff815b5885>] do_splice_from fs/splice.c:1128 [inline]
 [<ffffffff815b5885>] direct_splice_actor+0x125/0x180 fs/splice.c:1294
 [<ffffffff815b6b92>] splice_direct_to_actor+0x2d2/0x830 fs/splice.c:1247
 [<ffffffff815b7297>] do_splice_direct+0x1a7/0x270 fs/splice.c:1337
 [<ffffffff8152160c>] do_sendfile+0x54c/0xd30 fs/read_write.c:1227
 [<ffffffff81523663>] SYSC_sendfile64 fs/read_write.c:1282 [inline]
 [<ffffffff81523663>] SyS_sendfile64+0xc3/0x150 fs/read_write.c:1274
 [<ffffffff837796e5>] entry_SYSCALL_64_fastpath+0x22/0x9e
no locks held by syz-executor2/19800.
Sending NMI to all CPUs:
NMI backtrace for cpu 0
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.124-g851fb4d #60
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffffffff84217840 task.stack: ffffffff84200000
RIP: 0010:[<ffffffff810d0666>]  [<ffffffff810d0666>] native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:49
RSP: 0018:ffffffff84207dc0  EFLAGS: 00000246
RAX: 0000000000000007 RBX: ffffffff847deac8 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffffff8421811c
RBP: ffffffff84207dc0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: fffffbfff07088c0 R14: ffffffff847ece38 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000ad8d60 CR3: 00000001c8396000 CR4: 0000000000160670
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff84207df8 ffffffff81027e85 ffffffff84208000 ffffffff847deac8
 fffffbfff07088c0 ffffffff847ece38 0000000000000000 ffffffff84207e08
 ffffffff810293fa ffffffff84207e20 ffffffff812217c8 dffffc0000000000
Call Trace:
 [<ffffffff81027e85>] arch_safe_halt arch/x86/include/asm/paravirt.h:117 [inline]
 [<ffffffff81027e85>] default_idle+0x55/0x3c0 arch/x86/kernel/process.c:290
 [<ffffffff810293fa>] arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:281
 [<ffffffff812217c8>] default_idle_call+0x48/0x70 kernel/sched/idle.c:93
 [<ffffffff81221ecd>] cpuidle_idle_call kernel/sched/idle.c:157 [inline]
 [<ffffffff81221ecd>] cpu_idle_loop kernel/sched/idle.c:253 [inline]
 [<ffffffff81221ecd>] cpu_startup_entry+0x5fd/0x8f0 kernel/sched/idle.c:301
 [<ffffffff83766529>] rest_init+0x189/0x190 init/main.c:410
 [<ffffffff84823811>] start_kernel+0x6b9/0x6ee init/main.c:682
 [<ffffffff84822312>] x86_64_start_reservations+0x2a/0x2c arch/x86/kernel/head64.c:196
 [<ffffffff84822454>] x86_64_start_kernel+0x140/0x163 arch/x86/kernel/head64.c:185
Code: 00 00 00 00 00 55 48 89 e5 fa 5d c3 66 0f 1f 84 00 00 00 00 00 55 48 89 e5 fb 5d c3 66 0f 1f 84 00 00 00 00 00 55 48 89 e5 fb f4 <5d> c3 0f 1f 84 00 00 00 00 00 55 48 89 e5 f4 5d c3 66 0f 1f 84 
NMI backtrace for cpu 1
CPU: 1 PID: 486 Comm: khungtaskd Not tainted 4.4.124-g851fb4d #60
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8800bac99800 task.stack: ffff8800bbae8000
RIP: 0010:[<ffffffff810c3fa7>]  [<ffffffff810c3fa7>] native_apic_mem_write arch/x86/include/asm/apic.h:94 [inline]
RIP: 0010:[<ffffffff810c3fa7>]  [<ffffffff810c3fa7>] __default_send_IPI_dest_field arch/x86/include/asm/ipi.h:119 [inline]
RIP: 0010:[<ffffffff810c3fa7>]  [<ffffffff810c3fa7>] _flat_send_IPI_mask arch/x86/kernel/apic/apic_flat_64.c:61 [inline]
RIP: 0010:[<ffffffff810c3fa7>]  [<ffffffff810c3fa7>] flat_send_IPI_mask+0xf7/0x1a0 arch/x86/kernel/apic/apic_flat_64.c:69
RSP: 0018:ffff8800bbaefcb8  EFLAGS: 00000046
RAX: 0000000003000000 RBX: 0000000000000c00 RCX: 0000000000000000
RDX: 0000000000000c00 RSI: 0000000000000000 RDI: ffffffffff5fb300
RBP: ffff8800bbaefce0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000246
R13: 0000000000000003 R14: ffffffff8426f5a0 R15: 0000000000000002
FS:  0000000000000000(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000001f9d000 CR3: 00000001c8396000 CR4: 0000000000160670
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff8426f5a0 ffffffff847f09c0 fffffbfff08fdbec dffffc0000000000
 ffff8801db31bca0 ffff8800bbaefd00 ffffffff810b9adb ffffffff839f6e40
 0000000000000003 ffff8800bbaefd60 ffffffff81d115a4 0000000000000000
Call Trace:
 [<ffffffff810b9adb>] nmi_raise_cpu_backtrace+0x5b/0x70 arch/x86/kernel/apic/hw_nmi.c:33
 [<ffffffff81d115a4>] nmi_trigger_all_cpu_backtrace+0x4a4/0x550 lib/nmi_backtrace.c:85
 [<ffffffff810b9b74>] arch_trigger_all_cpu_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 [<ffffffff8136944a>] trigger_all_cpu_backtrace include/linux/nmi.h:44 [inline]
 [<ffffffff8136944a>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff8136944a>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff8136944a>] watchdog+0x6fa/0xae0 kernel/hung_task.c:238
 [<ffffffff811909c8>] kthread+0x268/0x300 kernel/kthread.c:211
 [<ffffffff83779b15>] ret_from_fork+0x55/0x80 arch/x86/entry/entry_64.S:510
Code: b3 5f ff f6 c4 10 75 e1 44 89 e8 c1 e0 18 89 04 25 10 b3 5f ff 44 89 fa 09 da 80 cf 04 41 83 ff 02 0f 44 d3 89 14 25 00 b3 5f ff <41> f7 c4 00 02 00 00 74 1a e8 8b 31 17 00 4c 89 e7 57 9d 0f 1f