INFO: task hung in cgrp_css

Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	INFO: task hung in cgrp_css_online net				3	2431d	2431d	0/28	closed as invalid on 2018/03/27 11:14

INFO: task syz-executor.1:3528 blocked for more than 143 seconds.
      Not tainted 5.15.160-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.1  state:D stack:20696 pid: 3528 ppid:     1 flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6376
 schedule+0x11b/0x1f0 kernel/sched/core.c:6459
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6518
 __mutex_lock_common+0xe34/0x25a0 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 cgrp_css_online+0x8c/0x2f0 net/core/netprio_cgroup.c:157
 online_css+0xba/0x260 kernel/cgroup/cgroup.c:5319
 css_create kernel/cgroup/cgroup.c:5390 [inline]
 cgroup_apply_control_enable+0x7d1/0xae0 kernel/cgroup/cgroup.c:3189
 cgroup_mkdir+0xdcd/0x1040 kernel/cgroup/cgroup.c:5587
 kernfs_iop_mkdir+0x275/0x400 fs/kernfs/dir.c:1175
 vfs_mkdir+0x3b6/0x590 fs/namei.c:4065
 do_mkdirat+0x260/0x520 fs/namei.c:4090
 __do_sys_mkdirat fs/namei.c:4105 [inline]
 __se_sys_mkdirat fs/namei.c:4103 [inline]
 __x64_sys_mkdirat+0x85/0x90 fs/namei.c:4103
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f509a7d1a67
RSP: 002b:00007ffe3a99dc98 EFLAGS: 00000202 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f509a82f633 RCX: 0