BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 41s! Showing busy workqueues and worker pools: workqueue events: flags=0x0 pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=3/256 pending: defense_work_handler, defense_work_handler, defense_work_handler workqueue kblockd: flags=0x18 pwq 1: cpus=0 node=0 flags=0x0 nice=-20 active=1/256 pending: blk_mq_requeue_work workqueue vmstat: flags=0xc pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 pending: vmstat_update workqueue dm_bufio_cache: flags=0x8 pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 pending: work_fn