syzbot

INFO: task syz-executor.5:1839 blocked for more than 140 seconds.
      Not tainted 4.14.156-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.5  D24560  1839      1 0x00000004
Call Trace:
 schedule+0x92/0x1c0 kernel/sched/core.c:3499
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3557
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x595/0x13e0 kernel/locking/mutex.c:893
 __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457
 blkdev_get+0x97/0x8b0 fs/block_dev.c:1612
 blkdev_open+0x1cc/0x250 fs/block_dev.c:1770
 do_dentry_open+0x44e/0xe20 fs/open.c:789
 vfs_open+0x105/0x230 fs/open.c:903
 do_last fs/namei.c:3539 [inline]
 path_openat+0xb6c/0x2be0 fs/namei.c:3681
 do_filp_open+0x1a1/0x280 fs/namei.c:3715
 do_sys_open+0x2ca/0x590 fs/open.c:1096
 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x4143f0
RSP: 002b:00007fffa8006c98 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 000000000002e76e RCX: 00000000004143f0
RDX: 00007fffa8006d2a RSI: 0000000000000002 RDI: 00007fffa8006d20
RBP: 00000000000001d3 R08: 0000000000000000 R09: 000000000000000a
R10: 0000000000000075 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fffa8006cd0 R14: 000000000002e6d4 R15: 00007fffa8006ce0
INFO: task syz-executor.3:8340 blocked for more than 140 seconds.
      Not tainted 4.14.156-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.3  D25312  8340      1 0x00000004
Call Trace:
 schedule+0x92/0x1c0 kernel/sched/core.c:3499
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3557
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x595/0x13e0 kernel/locking/mutex.c:893
 lo_open+0x19/0xb0 drivers/block/loop.c:1624
 __blkdev_get+0x267/0xf90 fs/block_dev.c:1472
 blkdev_get+0x97/0x8b0 fs/block_dev.c:1612
 blkdev_open+0x1cc/0x250 fs/block_dev.c:1770
 do_dentry_open+0x44e/0xe20 fs/open.c:789
 vfs_open+0x105/0x230 fs/open.c:903
 do_last fs/namei.c:3539 [inline]
 path_openat+0xb6c/0x2be0 fs/namei.c:3681
 do_filp_open+0x1a1/0x280 fs/namei.c:3715
 do_sys_open+0x2ca/0x590 fs/open.c:1096
 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x4143f0
RSP: 002b:00007ffc10b9b868 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 000000000002e772 RCX: 00000000004143f0
RDX: 00007ffc10b9b8fa RSI: 0000000000000002 RDI: 00007ffc10b9b8f0
RBP: 000000000000003c R08: 0000000000000000 R09: 000000000000000a
R10: 0000000000000075 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffc10b9b8a0 R14: 000000000002e708 R15: 00007ffc10b9b8b0
INFO: task syz-executor.1:8350 blocked for more than 140 seconds.
      Not tainted 4.14.156-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.1  D25312  8350      1 0x00000004
Call Trace:
 schedule+0x92/0x1c0 kernel/sched/core.c:3499
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3557
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x595/0x13e0 kernel/locking/mutex.c:893
 __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457
 blkdev_get+0x97/0x8b0 fs/block_dev.c:1612
 blkdev_open+0x1cc/0x250 fs/block_dev.c:1770
 do_dentry_open+0x44e/0xe20 fs/open.c:789
 vfs_open+0x105/0x230 fs/open.c:903
 do_last fs/namei.c:3539 [inline]
 path_openat+0xb6c/0x2be0 fs/namei.c:3681
 do_filp_open+0x1a1/0x280 fs/namei.c:3715
 do_sys_open+0x2ca/0x590 fs/open.c:1096
 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x4143f0
RSP: 002b:00007ffcd7ee3028 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 000000000002ea17 RCX: 00000000004143f0
RDX: 00007ffcd7ee30ba RSI: 0000000000000002 RDI: 00007ffcd7ee30b0
RBP: 0000000000000033 R08: 0000000000000000 R09: 000000000000000a
R10: 0000000000000075 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffcd7ee3060 R14: 000000000002e6ed R15: 00007ffcd7ee3070
INFO: task syz-executor.4:8892 blocked for more than 140 seconds.
      Not tainted 4.14.156-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.4  D25312  8892      1 0x00000004
Call Trace:
 schedule+0x92/0x1c0 kernel/sched/core.c:3499
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3557
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x595/0x13e0 kernel/locking/mutex.c:893
 lo_open+0x19/0xb0 drivers/block/loop.c:1624
 __blkdev_get+0x267/0xf90 fs/block_dev.c:1472
 blkdev_get+0x97/0x8b0 fs/block_dev.c:1612
 blkdev_open+0x1cc/0x250 fs/block_dev.c:1770
 do_dentry_open+0x44e/0xe20 fs/open.c:789
 vfs_open+0x105/0x230 fs/open.c:903
 do_last fs/namei.c:3539 [inline]
 path_openat+0xb6c/0x2be0 fs/namei.c:3681
 do_filp_open+0x1a1/0x280 fs/namei.c:3715
 do_sys_open+0x2ca/0x590 fs/open.c:1096
 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x4143f0
RSP: 002b:00007ffc5df64ac8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 000000000002e76d RCX: 00000000004143f0
RDX: 00007ffc5df64b5a RSI: 0000000000000002 RDI: 00007ffc5df64b50
RBP: 0000000000000039 R08: 0000000000000000 R09: 000000000000000a
R10: 0000000000000075 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffc5df64b00 R14: 000000000002e6ca R15: 00007ffc5df64b10
INFO: task syz-executor.0:10095 blocked for more than 140 seconds.
      Not tainted 4.14.156-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.0  D28096 10095   9556 0x00000004
Call Trace:
 schedule+0x92/0x1c0 kernel/sched/core.c:3499
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3557
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x595/0x13e0 kernel/locking/mutex.c:893
 blkdev_reread_part+0x1b/0x40 block/ioctl.c:192
 loop_reread_partitions+0x7f/0x90 drivers/block/loop.c:614
 loop_set_status+0xbff/0x11f0 drivers/block/loop.c:1183
 loop_set_status64+0xa5/0x100 drivers/block/loop.c:1301
 lo_ioctl+0xd1/0x1a30 drivers/block/loop.c:1431
 __blkdev_driver_ioctl block/ioctl.c:297 [inline]
 blkdev_ioctl+0x8d0/0x1870 block/ioctl.c:594
 block_ioctl+0xd9/0x120 fs/block_dev.c:1881
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0xabe/0x1040 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692
 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45a4e7
RSP: 002b:00007f7125a299f8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f7125a2a6d4 RCX: 000000000045a4e7
RDX: 00007f7125a29ab0 RSI: 0000000000004c04 RDI: 0000000000000005
RBP: 0000000000000001 R08: 0000000000000000 R09: 000000000000000a
R10: 0000000000000075 R11: 0000000000000202 R12: 0000000000000004
R13: 0000000000000004 R14: 0000000000000005 R15: 00000000ffffffff
INFO: task syz-executor.0:10106 blocked for more than 140 seconds.
      Not tainted 4.14.156-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.0  D29104 10106   9556 0x00000004
Call Trace:
 schedule+0x92/0x1c0 kernel/sched/core.c:3499
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3557
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x595/0x13e0 kernel/locking/mutex.c:893
 lo_open+0x19/0xb0 drivers/block/loop.c:1624
 __blkdev_get+0x963/0xf90 fs/block_dev.c:1537
 blkdev_get+0x97/0x8b0 fs/block_dev.c:1612
 blkdev_open+0x1cc/0x250 fs/block_dev.c:1770
 do_dentry_open+0x44e/0xe20 fs/open.c:789
 vfs_open+0x105/0x230 fs/open.c:903
 do_last fs/namei.c:3539 [inline]
 path_openat+0xb6c/0x2be0 fs/namei.c:3681
 do_filp_open+0x1a1/0x280 fs/namei.c:3715
 do_sys_open+0x2ca/0x590 fs/open.c:1096
 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x414411
RSP: 002b:00007f7125a087a0 EFLAGS: 00000293 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 6666666666666667 RCX: 0000000000414411
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007f7125a08850
RBP: 000000000075bfc8 R08: 000000000000000f R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 00007f7125a096d4
R13: 00000000004ca412 R14: 00000000004e2ab8 R15: 00000000ffffffff
INFO: task syz-executor.0:10129 blocked for more than 140 seconds.
      Not tainted 4.14.156-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.0  D29152 10129   9556 0x00000004
Call Trace:
 schedule+0x92/0x1c0 kernel/sched/core.c:3499
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3557
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x595/0x13e0 kernel/locking/mutex.c:893
 __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457
 blkdev_get+0x97/0x8b0 fs/block_dev.c:1612
 blkdev_open+0x1cc/0x250 fs/block_dev.c:1770
 do_dentry_open+0x44e/0xe20 fs/open.c:789
 vfs_open+0x105/0x230 fs/open.c:903
 do_last fs/namei.c:3539 [inline]
 path_openat+0xb6c/0x2be0 fs/namei.c:3681
 do_filp_open+0x1a1/0x280 fs/namei.c:3715
 do_sys_open+0x2ca/0x590 fs/open.c:1096
 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x414411
RSP: 002b:00007f71259a57a0 EFLAGS: 00000293 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 6666666666666667 RCX: 0000000000414411
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007f71259a5850
RBP: 000000000075c1c0 R08: 000000000000000f R09: 0000000000000000
R10: 00007f71259a69d0 R11: 0000000000000293 R12: 00007f71259a66d4
R13: 00000000004ca412 R14: 00000000004e2ab8 R15: 00000000ffffffff
INFO: task syz-executor.2:10094 blocked for more than 140 seconds.
      Not tainted 4.14.156-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.2  D27376 10094   8880 0x00000004
Call Trace:
 schedule+0x92/0x1c0 kernel/sched/core.c:3499
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3557
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x595/0x13e0 kernel/locking/mutex.c:893
 loop_control_ioctl+0x183/0x310 drivers/block/loop.c:1997
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0xabe/0x1040 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692
 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45a679
RSP: 002b:00007f7cd45bec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045a679
RDX: 0000000000000000 RSI: 0000000000004c81 RDI: 0000000000000007
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f7cd45bf6d4
R13: 00000000004c40dc R14: 00000000004d8b58 R15: 00000000ffffffff
INFO: task syz-executor.2:10114 blocked for more than 140 seconds.
      Not tainted 4.14.156-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.2  D29856 10114   8880 0x00000004
Call Trace:
 schedule+0x92/0x1c0 kernel/sched/core.c:3499
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3557
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x595/0x13e0 kernel/locking/mutex.c:893
 loop_control_ioctl+0x71/0x310 drivers/block/loop.c:1983
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0xabe/0x1040 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692
 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45a679
RSP: 002b:00007f7cd459dc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045a679
RDX: 0000000000000000 RSI: 0000000000004c80 RDI: 0000000000000007
RBP: 000000000075bfc8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f7cd459e6d4
R13: 00000000004c40b1 R14: 00000000004d8b28 R15: 00000000ffffffff
INFO: task syz-executor.2:10121 blocked for more than 140 seconds.
      Not tainted 4.14.156-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.2  D27184 10121   8880 0x00000004
Call Trace:
 schedule+0x92/0x1c0 kernel/sched/core.c:3499
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3557
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x595/0x13e0 kernel/locking/mutex.c:893
 loop_control_ioctl+0x71/0x310 drivers/block/loop.c:1983
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0xabe/0x1040 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692
 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45a679
RSP: 002b:00007f7cd457cc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045a679
RDX: 0000000000000000 RSI: 0000000000004c80 RDI: 0000000000000008
RBP: 000000000075c070 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f7cd457d6d4
R13: 00000000004c40b1 R14: 00000000004d8b28 R15: 00000000ffffffff

Showing all locks held in the system:
1 lock held by khungtaskd/23:
 #0:  (tasklist_lock){.+.+}, at: [<00000000015b2699>] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4544
1 lock held by rsyslogd/1630:
 #0:  (&f->f_pos_lock){+.+.}, at: [<00000000c4cc23a2>] __fdget_pos+0xb5/0xd0 fs/file.c:769
2 locks held by getty/1758:
 #0:  (&tty->ldisc_sem){++++}, at: [<0000000080b465f6>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<00000000f828aba2>] n_tty_read+0x1f7/0x1700 drivers/tty/n_tty.c:2156
1 lock held by syz-executor.5/1839:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<00000000075b23db>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457
2 locks held by syz-executor.3/8340:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<00000000075b23db>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457
 #1:  (loop_index_mutex){+.+.}, at: [<0000000056a46b38>] lo_open+0x19/0xb0 drivers/block/loop.c:1624
1 lock held by syz-executor.1/8350:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<00000000075b23db>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457
2 locks held by syz-executor.4/8892:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<00000000075b23db>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457
 #1:  (loop_index_mutex){+.+.}, at: [<0000000056a46b38>] lo_open+0x19/0xb0 drivers/block/loop.c:1624
2 locks held by syz-executor.0/10095:
 #0:  (&lo->lo_ctl_mutex/1){+.+.}, at: [<0000000032bbf5af>] lo_ioctl+0x86/0x1a30 drivers/block/loop.c:1404
 #1:  (&bdev->bd_mutex){+.+.}, at: [<00000000aca1b368>] blkdev_reread_part+0x1b/0x40 block/ioctl.c:192
2 locks held by syz-executor.0/10106:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<00000000075b23db>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457
 #1:  (loop_index_mutex){+.+.}, at: [<0000000056a46b38>] lo_open+0x19/0xb0 drivers/block/loop.c:1624
1 lock held by syz-executor.0/10129:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<00000000075b23db>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457
2 locks held by syz-executor.2/10094:
 #0:  (loop_index_mutex){+.+.}, at: [<00000000941b13fe>] loop_control_ioctl+0x71/0x310 drivers/block/loop.c:1983
 #1:  (&lo->lo_ctl_mutex#2){+.+.}, at: [<00000000e36b2ab4>] loop_control_ioctl+0x183/0x310 drivers/block/loop.c:1997
1 lock held by syz-executor.2/10114:
 #0:  (loop_index_mutex){+.+.}, at: [<00000000941b13fe>] loop_control_ioctl+0x71/0x310 drivers/block/loop.c:1983
1 lock held by syz-executor.2/10121:
 #0:  (loop_index_mutex){+.+.}, at: [<00000000941b13fe>] loop_control_ioctl+0x71/0x310 drivers/block/loop.c:1983
1 lock held by syz-executor.2/10132:
 #0:  (loop_index_mutex){+.+.}, at: [<00000000941b13fe>] loop_control_ioctl+0x71/0x310 drivers/block/loop.c:1983
2 locks held by blkid/10098:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<00000000075b23db>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457
 #1:  (loop_index_mutex){+.+.}, at: [<0000000056a46b38>] lo_open+0x19/0xb0 drivers/block/loop.c:1624
2 locks held by blkid/10103:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<00000000075b23db>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457
 #1:  (loop_index_mutex){+.+.}, at: [<0000000056a46b38>] lo_open+0x19/0xb0 drivers/block/loop.c:1624
1 lock held by blkid/10108:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<00000000075b23db>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457

=============================================

NMI backtrace for cpu 0
CPU: 0 PID: 23 Comm: khungtaskd Not tainted 4.14.156-syzkaller #0
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0xe5/0x154 lib/dump_stack.c:58
 nmi_cpu_backtrace.cold+0x47/0x86 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x119/0x147 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:140 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline]
 watchdog+0x629/0xbe0 kernel/hung_task.c:274
 kthread+0x31f/0x430 kernel/kthread.c:232
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:404
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at pc 0xffffffffb4ca7033