INFO: task hung in kernfs

Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
android-414	INFO: task hung in kernfs_remove				1	1872d	1831d	0/1	auto-closed as invalid on 2019/08/31 16:46
RDX: 0000000000000004 RSI: 00007ffc69eb6930 RDI: 0000000000000007
RBP: 0000000000625500 R08: 00007ffc69ec4000 R09: 000001003f6f3638
R10: 000000000000edf7 R11: 0000000000000246 R12: 00000000022353f0
R13: 00007ffc69eb7987 R14: 0000000000000005 R15: 00000000021a2030
INFO: task kworker/u4:0:7 blocked for more than 140 seconds.
      Not tainted 4.19.84 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kworker/u4:0    D24960     7      2 0x80000000
Workqueue: netns cleanup_net
Call Trace:
 context_switch kernel/sched/core.c:2826 [inline]
 __schedule+0x866/0x1dc0 kernel/sched/core.c:3515
 schedule+0x92/0x1c0 kernel/sched/core.c:3559
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3617
 __mutex_lock_common kernel/locking/mutex.c:1002 [inline]
 __mutex_lock+0x726/0x1300 kernel/locking/mutex.c:1072
Mem-Info:
active_anon:1356840 inactive_anon:255 isolated_anon:0
 active_file:40 inactive_file:90 isolated_file:28
 unevictable:0 dirty:0 writeback:0 unstable:0
 slab_reclaimable:14542 slab_unreclaimable:117160
 mapped:52299 shmem:325 pagetables:8874 bounce:0
 free:24964 free_pcp:0 free_cma:0
Node 0 active_anon:1729884kB inactive_anon:1020kB active_file:84kB inactive_file:444kB unevictable:0kB isolated(anon):0kB isolated(file):96kB mapped:209320kB dirty:0kB writeback:0kB shmem:1300kB shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 98304kB writeback_tmp:0kB unstable:0kB all_unreclaimable? no
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1087
 kernfs_remove+0x1c/0x40 fs/kernfs/dir.c:1351
 sysfs_remove_dir+0xd2/0x110 fs/sysfs/dir.c:101
 kobject_del.part.0+0x3a/0xf0 lib/kobject.c:592
 kobject_del lib/kobject.c:588 [inline]
 kobject_cleanup lib/kobject.c:656 [inline]
 kobject_release lib/kobject.c:691 [inline]
 kref_put include/linux/kref.h:70 [inline]
 kobject_put.cold+0x1f9/0x2e6 lib/kobject.c:708
 net_rx_queue_update_kobjects+0x361/0x480 net/core/net-sysfs.c:979
Node 1 active_anon:3697476kB inactive_anon:0kB active_file:0kB inactive_file:4kB unevictable:0kB isolated(anon):0kB isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB shmem:0kB shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB writeback_tmp:0kB unstable:0kB all_unreclaimable? yes
Node 0 DMA free:10440kB min:220kB low:272kB high:324kB active_anon:5396kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:15992kB managed:15908kB mlocked:0kB kernel_stack:0kB pagetables:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
lowmem_reserve[]: 0 2555 2557 2557
 remove_queue_kobjects net/core/net-sysfs.c:1567 [inline]
 netdev_unregister_kobject+0x155/0x1f0 net/core/net-sysfs.c:1718
Node 0 DMA32 free:35800kB min:36248kB low:45308kB high:54368kB active_anon:1724500kB inactive_anon:1020kB active_file:124kB inactive_file:240kB unevictable:0kB writepending:0kB present:3129332kB managed:2619976kB mlocked:0kB kernel_stack:15488kB pagetables:18528kB bounce:0kB free_pcp:616kB local_pcp:440kB free_cma:0kB
 rollback_registered_many+0x6bb/0xda0 net/core/dev.c:8029
lowmem_reserve[]: 0 0 2 2
Node 0 Normal free:8kB min:32kB low:40kB high:48kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:786432kB managed:2428kB mlocked:0kB kernel_stack:0kB pagetables:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB