=============================
WARNING: suspicious RCU usage
syzkaller #0 Not tainted
-----------------------------
io_uring/eventfd.c:160 suspicious rcu_dereference_protected() usage!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 1
2 locks held by kworker/u10:12/3941:
 #0: ffff888168f41148 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_one_work+0x841/0x15a0 kernel/workqueue.c:3236
 #1: ffffc90021f3fb80 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x868/0x15a0 kernel/workqueue.c:3237

stack backtrace:
CPU: 1 UID: 0 PID: 3941 Comm: kworker/u10:12 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Workqueue: iou_exit io_ring_exit_work
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 lockdep_rcu_suspicious+0x140/0x1d0 kernel/locking/lockdep.c:6876
 io_eventfd_unregister+0x18b/0x1c0 io_uring/eventfd.c:159
 io_ring_ctx_free+0x18a/0x820 io_uring/io_uring.c:2882
 io_ring_exit_work+0xe71/0x1030 io_uring/io_uring.c:3110
 process_one_work+0x93a/0x15a0 kernel/workqueue.c:3261
 process_scheduled_works kernel/workqueue.c:3344 [inline]
 worker_thread+0x9b0/0xee0 kernel/workqueue.c:3425
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>