INFO: task syz-executor.2:7022 blocked for more than 140 seconds.
      Not tainted 4.14.114 #4
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.2  D24832  7022      1 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2807 [inline]
 __schedule+0x7be/0x1cf0 kernel/sched/core.c:3383
 schedule+0x92/0x1c0 kernel/sched/core.c:3427
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3485
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
 __lo_release drivers/block/loop.c:1644 [inline]
 lo_release+0x84/0x1b0 drivers/block/loop.c:1668
 __blkdev_put+0x436/0x7f0 fs/block_dev.c:1791
 blkdev_put+0x88/0x510 fs/block_dev.c:1856
 blkdev_close+0x8b/0xb0 fs/block_dev.c:1863
 __fput+0x277/0x7a0 fs/file_table.c:210
 ____fput+0x16/0x20 fs/file_table.c:244
 task_work_run+0x119/0x190 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x1da/0x220 arch/x86/entry/common.c:163
 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:267 [inline]
 do_syscall_64+0x4a9/0x630 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x412b40
RSP: 002b:00007ffd76755498 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000412b40
RDX: 0000000000000000 RSI: 0000000000004c01 RDI: 0000000000000003
RBP: 0000000000000655 R08: 0000000000000000 R09: 000000000000000a
R10: 0000000000000075 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffd767554d0 R14: 000000000005ea32 R15: 00007ffd767554e0
INFO: task syz-executor.1:7024 blocked for more than 140 seconds.
      Not tainted 4.14.114 #4
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.1  D25168  7024      1 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2807 [inline]
 __schedule+0x7be/0x1cf0 kernel/sched/core.c:3383
 schedule+0x92/0x1c0 kernel/sched/core.c:3427
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3485
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
 lo_release+0x1e/0x1b0 drivers/block/loop.c:1667
 __blkdev_put+0x436/0x7f0 fs/block_dev.c:1791
 blkdev_put+0x88/0x510 fs/block_dev.c:1856
 blkdev_close+0x8b/0xb0 fs/block_dev.c:1863
 __fput+0x277/0x7a0 fs/file_table.c:210
 ____fput+0x16/0x20 fs/file_table.c:244
 task_work_run+0x119/0x190 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x1da/0x220 arch/x86/entry/common.c:163
 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:267 [inline]
 do_syscall_64+0x4a9/0x630 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x412b40
RSP: 002b:00007ffdee9f3248 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000412b40
RDX: 0000000000000000 RSI: 0000000000004c01 RDI: 0000000000000003
RBP: 000000000000052c R08: 0000000000000000 R09: 000000000000000a
R10: 0000000000000075 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffdee9f3280 R14: 000000000005e93d R15: 00007ffdee9f3290
INFO: task syz-executor.5:19399 blocked for more than 140 seconds.
      Not tainted 4.14.114 #4
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.5  D27040 19399   7021 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2807 [inline]
 __schedule+0x7be/0x1cf0 kernel/sched/core.c:3383
 schedule+0x92/0x1c0 kernel/sched/core.c:3427
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3485
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
 lo_ioctl+0x87/0x1c70 drivers/block/loop.c:1405
 __blkdev_driver_ioctl block/ioctl.c:297 [inline]
 blkdev_ioctl+0x983/0x1880 block/ioctl.c:594
 block_ioctl+0xde/0x120 fs/block_dev.c:1881
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x7b9/0x1070 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692
 do_syscall_64+0x1eb/0x630 arch/x86/entry/common.c:289
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x458c17
RSP: 002b:00007f9543a7d9f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f9543a7e6d4 RCX: 0000000000458c17
RDX: 0000000000000000 RSI: 0000000000004c01 RDI: 0000000000000004
RBP: 0000000000000000 R08: 0000000000000000 R09: 000000000000000c
R10: 0000000000000064 R11: 0000000000000246 R12: 0000000000000003
R13: 0000000000000000 R14: 0000000000000004 R15: 0000000000000001
INFO: task syz-executor.4:19402 blocked for more than 140 seconds.
      Not tainted 4.14.114 #4
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.4  D29024 19402   7025 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2807 [inline]
 __schedule+0x7be/0x1cf0 kernel/sched/core.c:3383
 schedule+0x92/0x1c0 kernel/sched/core.c:3427
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3485
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
 blkdev_reread_part+0x1f/0x40 block/ioctl.c:192
 loop_reread_partitions+0x7c/0x90 drivers/block/loop.c:615
 loop_set_status+0xc28/0x1200 drivers/block/loop.c:1184
 loop_set_status64+0xa6/0xf0 drivers/block/loop.c:1302
 lo_ioctl+0x5c1/0x1c70 drivers/block/loop.c:1432
 __blkdev_driver_ioctl block/ioctl.c:297 [inline]
 blkdev_ioctl+0x983/0x1880 block/ioctl.c:594
 block_ioctl+0xde/0x120 fs/block_dev.c:1881
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x7b9/0x1070 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692
 do_syscall_64+0x1eb/0x630 arch/x86/entry/common.c:289
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x458c17
RSP: 002b:00007f880bf5f9f8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f880bf606d4 RCX: 0000000000458c17
RDX: 00007f880bf5fab0 RSI: 0000000000004c04 RDI: 0000000000000004
RBP: 0000000000000001 R08: 0000000000000000 R09: 000000000000000a
R10: 0000000000000075 R11: 0000000000000202 R12: 0000000000000003
R13: 0000000000000003 R14: 0000000000000004 R15: 00000000ffffffff
INFO: task blkid:19401 blocked for more than 140 seconds.
      Not tainted 4.14.114 #4
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
blkid           D29040 19401   6641 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2807 [inline]
 __schedule+0x7be/0x1cf0 kernel/sched/core.c:3383
 schedule+0x92/0x1c0 kernel/sched/core.c:3427
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3485
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
 lo_open+0x1d/0xb0 drivers/block/loop.c:1624
 __blkdev_get+0xab1/0x1120 fs/block_dev.c:1537
 blkdev_get+0xa8/0x8e0 fs/block_dev.c:1612
 blkdev_open+0x1d1/0x260 fs/block_dev.c:1770
 do_dentry_open+0x73e/0xeb0 fs/open.c:758
 vfs_open+0x105/0x230 fs/open.c:872
 do_last fs/namei.c:3425 [inline]
 path_openat+0x8bd/0x3f70 fs/namei.c:3566
 do_filp_open+0x18e/0x250 fs/namei.c:3600
 do_sys_open+0x2c5/0x430 fs/open.c:1065
 SYSC_open fs/open.c:1083 [inline]
 SyS_open+0x2d/0x40 fs/open.c:1078
 do_syscall_64+0x1eb/0x630 arch/x86/entry/common.c:289
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x7fd3af595120
RSP: 002b:00007ffef06394c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fd3af595120
RDX: 00007ffef063af40 RSI: 0000000000000000 RDI: 00007ffef063af40
RBP: 0000000000000000 R08: 0000000000000078 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000d76030
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000005
INFO: task blkid:19403 blocked for more than 140 seconds.
      Not tainted 4.14.114 #4
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
blkid           D29040 19403   6983 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2807 [inline]
 __schedule+0x7be/0x1cf0 kernel/sched/core.c:3383
 schedule+0x92/0x1c0 kernel/sched/core.c:3427
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3485
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
 lo_open+0x1d/0xb0 drivers/block/loop.c:1624
 __blkdev_get+0xab1/0x1120 fs/block_dev.c:1537
 blkdev_get+0xa8/0x8e0 fs/block_dev.c:1612
 blkdev_open+0x1d1/0x260 fs/block_dev.c:1770
 do_dentry_open+0x73e/0xeb0 fs/open.c:758
 vfs_open+0x105/0x230 fs/open.c:872
 do_last fs/namei.c:3425 [inline]
 path_openat+0x8bd/0x3f70 fs/namei.c:3566
 do_filp_open+0x18e/0x250 fs/namei.c:3600
 do_sys_open+0x2c5/0x430 fs/open.c:1065
 SYSC_open fs/open.c:1083 [inline]
 SyS_open+0x2d/0x40 fs/open.c:1078
 do_syscall_64+0x1eb/0x630 arch/x86/entry/common.c:289
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x7fb35f8be120
RSP: 002b:00007fff72481878 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fb35f8be120
RDX: 00007fff72482f40 RSI: 0000000000000000 RDI: 00007fff72482f40
RBP: 0000000000000000 R08: 0000000000000078 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000001753030
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000005
INFO: task blkid:19407 blocked for more than 140 seconds.
      Not tainted 4.14.114 #4
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
blkid           D29040 19407   7178 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2807 [inline]
 __schedule+0x7be/0x1cf0 kernel/sched/core.c:3383
 schedule+0x92/0x1c0 kernel/sched/core.c:3427
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3485
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
 __blkdev_get+0x145/0x1120 fs/block_dev.c:1457
 blkdev_get+0xa8/0x8e0 fs/block_dev.c:1612
 blkdev_open+0x1d1/0x260 fs/block_dev.c:1770
 do_dentry_open+0x73e/0xeb0 fs/open.c:758
 vfs_open+0x105/0x230 fs/open.c:872
 do_last fs/namei.c:3425 [inline]
 path_openat+0x8bd/0x3f70 fs/namei.c:3566
 do_filp_open+0x18e/0x250 fs/namei.c:3600
 do_sys_open+0x2c5/0x430 fs/open.c:1065
 SYSC_open fs/open.c:1083 [inline]
 SyS_open+0x2d/0x40 fs/open.c:1078
 do_syscall_64+0x1eb/0x630 arch/x86/entry/common.c:289
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x7fc27ecec120
RSP: 002b:00007ffe2f1aa778 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fc27ecec120
RDX: 00007ffe2f1acf33 RSI: 0000000000000000 RDI: 00007ffe2f1acf33
RBP: 0000000000000000 R08: 0000000000000078 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000017c1030
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000005
INFO: task blkid:19408 blocked for more than 140 seconds.
      Not tainted 4.14.114 #4
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
blkid           D28320 19408   7168 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2807 [inline]
 __schedule+0x7be/0x1cf0 kernel/sched/core.c:3383
 schedule+0x92/0x1c0 kernel/sched/core.c:3427
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3485
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
 __blkdev_get+0x145/0x1120 fs/block_dev.c:1457
 blkdev_get+0xa8/0x8e0 fs/block_dev.c:1612
 blkdev_open+0x1d1/0x260 fs/block_dev.c:1770
 do_dentry_open+0x73e/0xeb0 fs/open.c:758
 vfs_open+0x105/0x230 fs/open.c:872
 do_last fs/namei.c:3425 [inline]
 path_openat+0x8bd/0x3f70 fs/namei.c:3566
 do_filp_open+0x18e/0x250 fs/namei.c:3600
 do_sys_open+0x2c5/0x430 fs/open.c:1065
 SYSC_open fs/open.c:1083 [inline]
 SyS_open+0x2d/0x40 fs/open.c:1078
 do_syscall_64+0x1eb/0x630 arch/x86/entry/common.c:289
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x7ff029319120
RSP: 002b:00007ffcf215e118 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007ff029319120
RDX: 00007ffcf215ff33 RSI: 0000000000000000 RDI: 00007ffcf215ff33
RBP: 0000000000000000 R08: 0000000000000078 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000124d030
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000005

Showing all locks held in the system:
1 lock held by khungtaskd/1007:
 #0:  (tasklist_lock){.+.+}, at: [<ffffffff81487148>] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4541
2 locks held by getty/6976:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff861af743>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8310d3c6>] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/6977:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff861af743>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8310d3c6>] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/6978:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff861af743>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8310d3c6>] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/6979:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff861af743>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8310d3c6>] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/6980:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff861af743>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8310d3c6>] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/6981:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff861af743>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8310d3c6>] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/6982:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff861af743>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8310d3c6>] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
3 locks held by syz-executor.2/7022:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<ffffffff819a7b16>] __blkdev_put+0xa6/0x7f0 fs/block_dev.c:1778
 #1:  (loop_index_mutex){+.+.}, at: [<ffffffff8373bf4e>] lo_release+0x1e/0x1b0 drivers/block/loop.c:1667
 #2:  (loop_ctl_mutex#2){+.+.}, at: [<ffffffff8373bfb4>] __lo_release drivers/block/loop.c:1644 [inline]
 #2:  (loop_ctl_mutex#2){+.+.}, at: [<ffffffff8373bfb4>] lo_release+0x84/0x1b0 drivers/block/loop.c:1668
2 locks held by syz-executor.1/7024:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<ffffffff819a7b16>] __blkdev_put+0xa6/0x7f0 fs/block_dev.c:1778
 #1:  (loop_index_mutex){+.+.}, at: [<ffffffff8373bf4e>] lo_release+0x1e/0x1b0 drivers/block/loop.c:1667
1 lock held by syz-executor.5/19399:
 #0:  (loop_ctl_mutex/1){+.+.}, at: [<ffffffff8373dc27>] lo_ioctl+0x87/0x1c70 drivers/block/loop.c:1405
2 locks held by syz-executor.4/19402:
 #0:  (loop_ctl_mutex/1){+.+.}, at: [<ffffffff8373dc27>] lo_ioctl+0x87/0x1c70 drivers/block/loop.c:1405
 #1:  (&bdev->bd_mutex){+.+.}, at: [<ffffffff82cab2af>] blkdev_reread_part+0x1f/0x40 block/ioctl.c:192
2 locks held by blkid/19401:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<ffffffff819a83a5>] __blkdev_get+0x145/0x1120 fs/block_dev.c:1457
 #1:  (loop_index_mutex){+.+.}, at: [<ffffffff8373739d>] lo_open+0x1d/0xb0 drivers/block/loop.c:1624
2 locks held by blkid/19403:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<ffffffff819a83a5>] __blkdev_get+0x145/0x1120 fs/block_dev.c:1457
 #1:  (loop_index_mutex){+.+.}, at: [<ffffffff8373739d>] lo_open+0x1d/0xb0 drivers/block/loop.c:1624
1 lock held by blkid/19407:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<ffffffff819a83a5>] __blkdev_get+0x145/0x1120 fs/block_dev.c:1457
1 lock held by blkid/19408:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<ffffffff819a83a5>] __blkdev_get+0x145/0x1120 fs/block_dev.c:1457

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

NMI backtrace for cpu 1
CPU: 1 PID: 1007 Comm: khungtaskd Not tainted 4.14.114 #4
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x138/0x19c lib/dump_stack.c:53
 nmi_cpu_backtrace.cold+0x57/0x94 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x141/0x189 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 trigger_all_cpu_backtrace include/linux/nmi.h:140 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline]
 watchdog+0x5e7/0xb90 kernel/hung_task.c:274
 kthread+0x31c/0x430 kernel/kthread.c:232
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:402
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 10592 Comm: kworker/u4:7 Not tainted 4.14.114 #4
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: bat_events batadv_nc_worker
task: ffff88805e6c2040 task.stack: ffff88805d180000
RIP: 0010:__lock_acquire+0x188/0x45e0 kernel/locking/lockdep.c:3344
RSP: 0018:ffff88805d187a10 EFLAGS: 00000086
RAX: ffffed100ba30f56 RBX: ffffffff886c7ca0 RCX: 000000000e8b7eb4
RDX: 1ffff1100bcd8517 RSI: ffff88805e6c2910 RDI: ffffffff886c7cb8
RBP: ffff88805d187bc0 R08: 0000000000000496 R09: ffffffff88c7b8b0
R10: ffff88805e6c2910 R11: ffff88805e6c2040 R12: 0000000000000001
R13: dffffc0000000000 R14: ffffffff88c7b8b0 R15: e49b60cd2254c5e9
FS:  0000000000000000(0000) GS:ffff8880aee00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8b6c0583b8 CR3: 000000007f964000 CR4: 00000000001406f0
DR0: 0000000000000004 DR1: 0000000000000000 DR2: 000000000001d001
DR3: 0000000000007004 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 lock_acquire+0x16f/0x430 kernel/locking/lockdep.c:3991
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline]
 _raw_spin_lock_bh+0x33/0x50 kernel/locking/spinlock.c:176
 spin_lock_bh include/linux/spinlock.h:322 [inline]
 batadv_nc_purge_paths+0xcb/0x350 net/batman-adv/network-coding.c:450
 batadv_nc_worker+0x23d/0x6d0 net/batman-adv/network-coding.c:727
 process_one_work+0x868/0x1610 kernel/workqueue.c:2114
 worker_thread+0x5d9/0x1050 kernel/workqueue.c:2248
 kthread+0x31c/0x430 kernel/kthread.c:232
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:402
Code: 80 00 00 00 4c 8b 5c 24 78 0f 85 a0 00 00 00 45 31 e4 48 b8 00 00 00 00 00 fc ff df 48 03 84 24 98 00 00 00 48 c7 00 00 00 00 00 <48> c7 40 08 00 00 00 00 c7 40 18 00 00 00 00 48 8d 65 d8 44 89