INFO: task jbd2/sda1-8:1907 blocked for more than 120 seconds.
      Not tainted 4.4.133-g3f51ea2 #49
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
jbd2/sda1-8     D ffff8800b6b47590 26112  1907      2 0x00000000
 ffff8800b6b47590 0000000000000000 0000000000000000 0000000000000002
 0000000000000000 ffff8801db21fdb8 ffff8801db21fde0 ffff8801db21f4d8
 ffff8801db21f4c0 ffff8801d99a8000 ffff8800b6446000 0000000000000000
Call Trace:
 [<ffffffff838b2f2a>] schedule+0x7a/0x1b0 kernel/sched/core.c:3359
 [<ffffffff838be341>] schedule_timeout+0x481/0x8b0 kernel/time/timer.c:1515
 [<ffffffff838b0dea>] io_schedule_timeout+0x1ba/0x390 kernel/sched/core.c:4941
 [<ffffffff838b417b>] io_schedule include/linux/sched.h:447 [inline]
 [<ffffffff838b417b>] bit_wait_io+0x1b/0xd0 kernel/sched/wait.c:595
 [<ffffffff838b390d>] __wait_on_bit+0xbd/0x140 kernel/sched/wait.c:395
 [<ffffffff838b3a78>] out_of_line_wait_on_bit+0xe8/0x120 kernel/sched/wait.c:408
 [<ffffffff815c505c>] wait_on_bit_io include/linux/wait.h:1015 [inline]
 [<ffffffff815c505c>] __wait_on_buffer+0x5c/0x70 fs/buffer.c:123
 [<ffffffff81823b55>] wait_on_buffer include/linux/buffer_head.h:342 [inline]
 [<ffffffff81823b55>] journal_wait_on_commit_record fs/jbd2/commit.c:178 [inline]
 [<ffffffff81823b55>] jbd2_journal_commit_transaction+0x4725/0x65a0 fs/jbd2/commit.c:895
 [<ffffffff8183299a>] kjournald2+0x22a/0x830 fs/jbd2/journal.c:223
 [<ffffffff81190818>] kthread+0x268/0x300 kernel/kthread.c:211
 [<ffffffff838c1395>] ret_from_fork+0x55/0x80 arch/x86/entry/entry_64.S:510
no locks held by jbd2/sda1-8/1907.
Sending NMI to all CPUs:
NMI backtrace for cpu 0
CPU: 0 PID: 491 Comm: khungtaskd Not tainted 4.4.133-g3f51ea2 #49
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8800baccc800 task.stack: ffff8801d9210000
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:ffff8801d9217cc8  EFLAGS: 00000046
RAX: 0000000003000000 RBX: 0000000000000c00 RCX: 0000000000000000
RDX: 0000000000000c00 RSI: 0000000000000000 RDI: ffffffffff5fb300
RBP: ffff8801d9217cf0 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: 000000000811c0b4 CR3: 00000001d4244000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff8446f7a0 ffffffff84a18ae0 0000000000000007 fffffbfff0942c0c
 0000000000000040 ffff8801d9217d10 ffffffff810b5dd1 ffffffff83c0b220
 0000000000000003 ffff8801d9217d68 ffffffff81e19543 ffff8800b6446000
Call Trace:
 [<ffffffff810b5dd1>] nmi_raise_cpu_backtrace+0x61/0x80 arch/x86/kernel/apic/hw_nmi.c:33
 [<ffffffff81e19543>] 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
 [<ffffffff8141a209>] trigger_all_cpu_backtrace include/linux/nmi.h:44 [inline]
 [<ffffffff8141a209>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff8141a209>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff8141a209>] watchdog.cold.1+0xd3/0xee kernel/hung_task.c:238
 [<ffffffff81190818>] kthread+0x268/0x300 kernel/kthread.c:211
 [<ffffffff838c1395>] 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 a2 
NMI backtrace for cpu 1
CPU: 1 PID: 32081 Comm: syz-executor6 Not tainted 4.4.133-g3f51ea2 #49
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff88009a20b000 task.stack: ffff8801a7c30000
RIP: 0010:[<ffffffff81583d19>]  [<ffffffff81583d19>] __lookup_mnt+0xb9/0x120 fs/namespace.c:641
RSP: 0018:ffff8801a7c37ac8  EFLAGS: 00000246
RAX: 1ffff10037469182 RBX: ffff8801ba348c00 RCX: ffffc9000ad19000
RDX: 0000000000040000 RSI: ffffffff81583d09 RDI: ffff8801ba348c10
RBP: ffff8801a7c37ae8 R08: ffff8801a7c37c10 R09: 0000000000000000
R10: 0000000000000001 R11: ffff88009a20b000 R12: ffff8801a803de20
R13: ffff8801ce19b8c0 R14: dffffc0000000000 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8801db300000(0063) knlGS:00000000f5698b40
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 00007f35aa4d6140 CR3: 00000000b593c000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffff8801d2d27ac0 ffff8801d2d27ac0 ffff8801abaa3108 ffff8801a803de00
 ffff8801a7c37c78 ffffffff815b3b68 ffff88009a20b000 ffff8800b719ec18
 ffff8801a7c37ce0 1ffff10034f86f6e ffff8801a7c37c10 ffff8801bb903800
Call Trace:
 [<ffffffff815b3b68>] propagate_umount+0x3e8/0xdb0 fs/pnode.c:568
 [<ffffffff8157e9f5>] umount_tree+0x695/0x810 fs/namespace.c:1471
 [<ffffffff81582acc>] do_umount+0x31c/0x830 fs/namespace.c:1585
 [<ffffffff8158514f>] SYSC_umount fs/namespace.c:1684 [inline]
 [<ffffffff8158514f>] SyS_umount+0x2ff/0x3f0 fs/namespace.c:1653
 [<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
 [<ffffffff838c28aa>] sysenter_flags_fixed+0xd/0x17
Code: e8 03 42 80 3c 30 00 75 6a 48 8b 1b e8 a1 35 cf ff 48 85 db 74 52 e8 27 d6 dc ff 48 8d 7b 10 48 89 f8 48 c1 e8 03 42 80 3c 30 00 <75> 3f 48 8b 43 10 48 83 c0 20 49 39 c4 75 bc e8 03 d6 dc ff 48