Node 0 DMA free:10440kB min:220kB low:272kB high:324kB active_anon:5256kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:15992kB managed:15908kB mlocked:0kB kernel_stack:32kB pagetables:16kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
INFO: task blkid:23453 blocked for more than 140 seconds.
      Not tainted 5.0.0 #4
lowmem_reserve[]: 0 2553 2555 2555
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
Node 0 DMA32 free:36872kB min:38280kB low:47336kB high:56392kB active_anon:1800436kB inactive_anon:776kB active_file:104kB inactive_file:208kB unevictable:0kB writepending:0kB present:3129332kB managed:2617972kB mlocked:0kB kernel_stack:9408kB pagetables:13344kB bounce:0kB free_pcp:68kB local_pcp:8kB free_cma:0kB
blkid           D27312 23453   8056 0x80000006
Call Trace:
 context_switch kernel/sched/core.c:2844 [inline]
 __schedule+0x817/0x1cc0 kernel/sched/core.c:3485
 schedule+0x92/0x180 kernel/sched/core.c:3529
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3587
 __mutex_lock_common kernel/locking/mutex.c:1002 [inline]
 __mutex_lock+0x726/0x1310 kernel/locking/mutex.c:1072
lowmem_reserve[]: 0 0 2 2
Node 0 Normal free:12kB min:28kB low:32kB high:36kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:786432kB managed:2204kB mlocked:0kB kernel_stack:0kB pagetables:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1087
 kernfs_find_and_get_ns+0x26/0x70 fs/kernfs/dir.c:910
 kernfs_find_and_get include/linux/kernfs.h:494 [inline]
 sysfs_remove_group+0x76/0x1b0 fs/sysfs/group.c:252