=============================
WARNING: suspicious RCU usage
5.12.0-syzkaller #0 Not tainted
-----------------------------
kernel/sched/core.c:8304 Illegal context switch in RCU-sched read-side critical section!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 0
3 locks held by kworker/u4:3/151:
 #0: 
ffff8880115af938
 (
(wq_completion)netns
){+.+.}-{0:0}
, at: process_one_work+0x7aa/0x10c0 kernel/workqueue.c:2248
 #1: 
ffffc9000108fd20
 (
net_cleanup_work
){+.+.}-{0:0}
, at: process_one_work+0x7e8/0x10c0 kernel/workqueue.c:2250
 #2: 
ffffffff8dd0a430
 (
pernet_ops_rwsem
){++++}-{3:3}
, at: cleanup_net+0xf0/0xc60 net/core/net_namespace.c:557

stack backtrace:
CPU: 0 PID: 151 Comm: kworker/u4:3 Not tainted 5.12.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: netns cleanup_net
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x202/0x31e lib/dump_stack.c:120
 ___might_sleep+0x114/0x6b0 kernel/sched/core.c:8304
 inet_twsk_purge+0x105/0x8e0 net/ipv4/inet_timewait_sock.c:267
 ops_exit_list net/core/net_namespace.c:178 [inline]
 cleanup_net+0x7ec/0xc60 net/core/net_namespace.c:595
 process_one_work+0x833/0x10c0 kernel/workqueue.c:2275
 worker_thread+0xac1/0x1300 kernel/workqueue.c:2421
 kthread+0x39a/0x3c0 kernel/kthread.c:313
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294