syzbot

INFO: task syz-executor0:8759 blocked for more than 140 seconds.
      Not tainted 4.4.139-g7ba5557 #66
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor0   D ffff8801d46afb30 29232  8759   3883 0x00000004
 ffff8801d46afb30 ffff8801d2efe000 ffff8801d2efe8f8 ffffffff00000001
 ffff8801d2efe800 ffff8801db31fdb8 ffff8801db31fde0 ffff8801db31f4d8
 ffff8801db31f4c0 ffff8801bf74e000 ffff8801d2efe000 0000000000000000
Call Trace:
 [<ffffffff838b381a>] schedule+0x7a/0x1b0 kernel/sched/core.c:3359
 [<ffffffff838bec31>] schedule_timeout+0x481/0x8b0 kernel/time/timer.c:1515
 [<ffffffff838b695e>] do_wait_for_common kernel/sched/completion.c:75 [inline]
 [<ffffffff838b695e>] __wait_for_common kernel/sched/completion.c:93 [inline]
 [<ffffffff838b695e>] wait_for_common kernel/sched/completion.c:101 [inline]
 [<ffffffff838b695e>] wait_for_completion+0x1fe/0x2e0 kernel/sched/completion.c:122
 [<ffffffff81d5a0f9>] submit_bio_wait+0xf9/0x150 block/bio.c:887
 [<ffffffff81d8c724>] blkdev_issue_flush+0x124/0x1e0 block/blk-flush.c:488
 [<ffffffff815d08e5>] blkdev_fsync+0x85/0xb0 fs/block_dev.c:364
 [<ffffffff815bd55c>] vfs_fsync_range+0x10c/0x260 fs/sync.c:195
 [<ffffffff815bd722>] vfs_fsync fs/sync.c:209 [inline]
 [<ffffffff815bd722>] do_fsync+0x42/0xb0 fs/sync.c:219
 [<ffffffff815bdea6>] SYSC_fsync fs/sync.c:228 [inline]
 [<ffffffff815bdea6>] SyS_fsync+0x16/0x20 fs/sync.c:226
 [<ffffffff838c1865>] entry_SYSCALL_64_fastpath+0x22/0x9e
no locks held by syz-executor0/8759.
Sending NMI to all CPUs:
NMI backtrace for cpu 0
CPU: 0 PID: 492 Comm: khungtaskd Not tainted 4.4.139-g7ba5557 #66
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8800bac34800 task.stack: ffff8801d8cf0000
RIP: 0010:[<ffffffff810bfb46>]  [<ffffffff810bfb46>] native_apic_mem_write arch/x86/include/asm/apic.h:94 [inline]
RIP: 0010:[<ffffffff810bfb46>]  [<ffffffff810bfb46>] __default_send_IPI_dest_field arch/x86/include/asm/ipi.h:119 [inline]
RIP: 0010:[<ffffffff810bfb46>]  [<ffffffff810bfb46>] _flat_send_IPI_mask arch/x86/kernel/apic/apic_flat_64.c:61 [inline]
RIP: 0010:[<ffffffff810bfb46>]  [<ffffffff810bfb46>] flat_send_IPI_mask+0xf6/0x1a0 arch/x86/kernel/apic/apic_flat_64.c:69
RSP: 0018:ffff8801d8cf7cc8  EFLAGS: 00000046
RAX: 0000000003000000 RBX: 0000000000000c00 RCX: 0000000000000000
RDX: 0000000000000c00 RSI: 0000000000000000 RDI: ffffffffff5fb300
RBP: ffff8801d8cf7cf0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000246
R13: 0000000000000003 R14: 0000000000000002 R15: ffffffff8446f6a0
FS:  0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f98882f6000 CR3: 00000001d343a000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff8446f6a0 ffffffff84a18ca0 0000000000000007 fffffbfff0942c44
 0000000000000040 ffff8801d8cf7d10 ffffffff810b5b01 ffffffff83c0b2a0
 0000000000000003 ffff8801d8cf7d68 ffffffff81e18603 ffff8801d2efe000
Call Trace:
 [<ffffffff810b5b01>] nmi_raise_cpu_backtrace+0x61/0x80 arch/x86/kernel/apic/hw_nmi.c:33
 [<ffffffff81e18603>] nmi_trigger_all_cpu_backtrace.cold.4+0x70/0xad lib/nmi_backtrace.c:85
 [<ffffffff810b5ba4>] 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
 [<ffffffff838c1c95>] 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 e2 
NMI backtrace for cpu 1
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.4.139-g7ba5557 #66
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801d9a41800 task.stack: ffff8801d9a50000
RIP: 0010:[<ffffffff8122f8d9>]  [<ffffffff8122f8d9>] mark_irqflags kernel/locking/lockdep.c:2784 [inline]
RIP: 0010:[<ffffffff8122f8d9>]  [<ffffffff8122f8d9>] __lock_acquire+0x8a9/0x5270 kernel/locking/lockdep.c:3169
RSP: 0018:ffff8801d9a579c0  EFLAGS: 00000802
RAX: 0000000000000000 RBX: ffff8801d9a42108 RCX: 0000000000000001
RDX: ffff8801d9a4212a RSI: 0000000000000003 RDI: ffff8801d9a4212c
RBP: ffff8801d9a57b58 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000000 R11: ffff8801d9a41800 R12: 0000000000000002
R13: ffff8801d9a4212a R14: ffff8801d9a42129 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1188faa000 CR3: 00000001d343a000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffff88021fffd057 ffff88021fffd04f ffffed0043fffa0b ffff88021fffd05c
 ffff88021fffd048 ffffffff84472dc0 ffffffff85931640 dffffc0000000000
 000000000000cd42 ffff8801d9a420e0 ffff8801d9a42120 ffff8801d9a42102
Call Trace:
 [<ffffffff81235a7e>] lock_acquire+0x15e/0x450 kernel/locking/lockdep.c:3592
 [<ffffffff838c148e>] __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:112 [inline]
 [<ffffffff838c148e>] _raw_spin_lock_irqsave+0x4e/0x70 kernel/locking/spinlock.c:159
 [<ffffffff81e6efe7>] debug_object_deactivate+0xf7/0x340 lib/debugobjects.c:463
 [<ffffffff8129eb37>] debug_hrtimer_deactivate kernel/time/hrtimer.c:415 [inline]
 [<ffffffff8129eb37>] debug_deactivate kernel/time/hrtimer.c:462 [inline]
 [<ffffffff8129eb37>] remove_hrtimer kernel/time/hrtimer.c:952 [inline]
 [<ffffffff8129eb37>] hrtimer_try_to_cancel+0x197/0x660 kernel/time/hrtimer.c:1060
 [<ffffffff8129f022>] hrtimer_cancel+0x22/0x40 kernel/time/hrtimer.c:1080
 [<ffffffff812c5abe>] tick_nohz_restart+0x1e/0x190 kernel/time/tick-sched.c:559
 [<ffffffff812c7307>] tick_nohz_restart_sched_tick kernel/time/tick-sched.c:726 [inline]
 [<ffffffff812c7307>] tick_nohz_idle_exit+0x247/0x3d0 kernel/time/tick-sched.c:946
 [<ffffffff8121bfa7>] cpu_idle_loop kernel/sched/idle.c:267 [inline]
 [<ffffffff8121bfa7>] cpu_startup_entry+0x2a7/0x780 kernel/sched/idle.c:301
 [<ffffffff810a9e74>] start_secondary+0x324/0x400 arch/x86/kernel/smpboot.c:242
Code: 7f 08 84 c0 0f 85 e8 19 00 00 4c 8d 6b 22 44 0f b6 7b 21 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 0f b6 04 02 4c 89 ea <83> e2 07 38 d0 7f 08 84 c0 0f 85 76 19 00 00 45 84 ff 0f b6 43