INFO: task syz-executor.4:2112 blocked for more than 140 seconds.
      Not tainted 4.4.174+ #17
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.4  D ffff8800a64b75f8 24736  2112      1 0x20020004
 ffff8800a64b75f8 ffff8801d7fe5f00 989d53dccaf7a7d6 ffff8801d7fe5f00
 0000000000000000 ffff8801d7fe6700 ffff8801db71f180 ffff8801db71f1a8
 ffff8801db71e898 ffff8801da68df00 ffff8801d7fe5f00 ffffed0014c96001
Call Trace:
 [<ffffffff82709b79>] schedule+0x99/0x1d0 kernel/sched/core.c:3355
 [<ffffffff8270a333>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3388
 [<ffffffff8270c492>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<ffffffff8270c492>] mutex_lock_nested+0x3c2/0xb80 kernel/locking/mutex.c:621
 [<ffffffff8154e9cc>] __blkdev_get+0x10c/0xdf0 fs/block_dev.c:1199
 [<ffffffff81551938>] blkdev_get+0x2e8/0x920 fs/block_dev.c:1353
 [<ffffffff8155219a>] blkdev_open+0x1aa/0x250 fs/block_dev.c:1508
 [<ffffffff8149154f>] do_dentry_open+0x38f/0xbd0 fs/open.c:749
 [<ffffffff81494d3b>] vfs_open+0x10b/0x210 fs/open.c:862
 [<ffffffff814c5ddf>] do_last fs/namei.c:3269 [inline]
 [<ffffffff814c5ddf>] path_openat+0x136f/0x4470 fs/namei.c:3406
 [<ffffffff814ccab1>] do_filp_open+0x1a1/0x270 fs/namei.c:3440
 [<ffffffff81495668>] do_sys_open+0x2f8/0x600 fs/open.c:1038
 [<ffffffff81599c4a>] C_SYSC_open fs/compat.c:1092 [inline]
 [<ffffffff81599c4a>] compat_SyS_open+0x2a/0x40 fs/compat.c:1090
 [<ffffffff8100603d>] do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline]
 [<ffffffff8100603d>] do_fast_syscall_32+0x32d/0xa90 arch/x86/entry/common.c:397
 [<ffffffff8271a350>] sysenter_flags_fixed+0xd/0x1a
1 lock held by syz-executor.4/2112:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff8154e9cc>] __blkdev_get+0x10c/0xdf0 fs/block_dev.c:1199
Sending NMI to all CPUs:
NMI backtrace for cpu 0
CPU: 0 PID: 20 Comm: khungtaskd Not tainted 4.4.174+ #17
task: ffff8801da6c5f00 task.stack: ffff8800001c8000
RIP: 0010:[<ffffffff8109b617>]  [<ffffffff8109b617>] _flat_send_IPI_mask arch/x86/kernel/apic/apic_flat_64.c:62 [inline]
RIP: 0010:[<ffffffff8109b617>]  [<ffffffff8109b617>] flat_send_IPI_mask+0xf7/0x1b0 arch/x86/kernel/apic/apic_flat_64.c:69
RSP: 0018:ffff8800001cfc88  EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000c00 RCX: 0000000000000000
RDX: 0000000000000c00 RSI: 0000000000000000 RDI: ffffffffff5fc300
RBP: ffff8800001cfcb8 R08: 0000000000000018 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000246
R13: 0000000003000000 R14: ffffffff82e5f2e0 R15: 0000000000000002
FS:  0000000000000000(0000) GS:ffff8801db600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000001f6e000 CR3: 00000001d8175000 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 0000000000000001 ffffffff82e5f2e0 ffffffff831a6ac0 fffffbfff0634c34
 000000000001b6c0 0000000000000008 ffff8800001cfcd8 ffffffff81092bee
 0000000000000008 ffffffff82924260 ffff8800001cfd30 ffffffff81ab8252
Call Trace:
 [<ffffffff81092bee>] nmi_raise_cpu_backtrace+0x5e/0x80 arch/x86/kernel/apic/hw_nmi.c:33
 [<ffffffff81ab8252>] nmi_trigger_all_cpu_backtrace.cold+0xa1/0xae lib/nmi_backtrace.c:85
 [<ffffffff81092ca4>] arch_trigger_all_cpu_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 [<ffffffff813b4762>] trigger_all_cpu_backtrace include/linux/nmi.h:44 [inline]
 [<ffffffff813b4762>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff813b4762>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff813b4762>] watchdog.cold+0xd3/0xee kernel/hung_task.c:238
 [<ffffffff811342c3>] kthread+0x273/0x310 kernel/kthread.c:211
 [<ffffffff82718fc5>] ret_from_fork+0x55/0x80 arch/x86/entry/entry_64.S:537
Code: 00 c3 5f ff 80 e6 10 75 e1 41 c1 e5 18 44 89 2c 25 10 c3 5f ff 44 89 fa 09 da 80 cf 04 41 83 ff 02 0f 44 d3 89 14 25 00 c3 5f ff <41> f7 c4 00 02 00 00 75 1e 4c 89 e7 57 9d 0f 1f 44 00 00 e8 f1 
NMI backtrace for cpu 1
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.4.174+ #17
task: ffff8801da6897c0 task.stack: ffff8801da698000
RIP: 0010:[<ffffffff81137dec>]  [<ffffffff81137dec>] __read_once_size include/linux/compiler.h:218 [inline]
RIP: 0010:[<ffffffff81137dec>]  [<ffffffff81137dec>] notifier_call_chain+0x3c/0x1e0 kernel/notifier.c:81
RSP: 0018:ffff8801da69fd00  EFLAGS: 00000246
RAX: dffffc0000000000 RBX: ffffffff82e6db18 RCX: 00000000ffffffff
RDX: 1ffffffff05cdb63 RSI: ffffffff81137dd7 RDI: ffffffff82e6db18
RBP: ffff8801da69fd50 R08: 0000000000000000 R09: ffff8801da68a0a8
R10: ffffffff82836880 R11: 0000000000000000 R12: 0000000000000002
R13: 00000000ffffffff R14: 00000000ffffffff R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8801db700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c420496000 CR3: 00000000ba08f000 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 0000000000000002 0000000000000000 0000000000000000 0000000000000002
 ffff8801da69fd30 ffffffff82e6dae0 0000000000000002 0000000000000000
 00000000ffffffff 0000000000000000 ffff8801da69fd90 ffffffff81138097
Call Trace:
 [<ffffffff81138097>] __atomic_notifier_call_chain+0x87/0x150 kernel/notifier.c:183
 [<ffffffff8113818e>] atomic_notifier_call_chain+0x2e/0x40 kernel/notifier.c:193
 [<ffffffff810d3f4f>] idle_notifier_call_chain+0x1f/0x30 kernel/cpu.c:865
 [<ffffffff81022cfe>] __exit_idle arch/x86/kernel/process.c:389 [inline]
 [<ffffffff81022cfe>] arch_cpu_idle_exit+0x1e/0x20 arch/x86/kernel/process.c:410
 [<ffffffff811eb816>] cpu_idle_loop kernel/sched/idle.c:255 [inline]
 [<ffffffff811eb816>] cpu_startup_entry+0x246/0x810 kernel/sched/idle.c:301
 [<ffffffff8108719d>] start_secondary+0x31d/0x410 arch/x86/kernel/smpboot.c:245
Code: 54 53 48 89 fb 48 83 ec 28 48 89 55 c0 48 89 75 c8 e8 19 18 1d 00 48 89 da 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 <0f> 85 8e 01 00 00 4c 8b 23 e8 f6 28 10 00 4d 85 e4 0f 84 34 01