------------[ cut here ]------------
WARNING: CPU: 1 PID: 52 at lib/percpu-refcount.c:112 __percpu_ref_exit+0x98/0x100 lib/percpu-refcount.c:112
Modules linked in:
CPU: 1 PID: 52 Comm: kworker/u4:2 Not tainted 5.10.0-next-20201223-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events_unbound io_ring_exit_work
RIP: 0010:__percpu_ref_exit+0x98/0x100 lib/percpu-refcount.c:112
Code: fd 49 8d 7c 24 10 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 61 49 83 7c 24 10 00 74 07 e8 f8 77 b6 fd <0f> 0b e8 f1 77 b6 fd 48 89 ef e8 a9 8b e4 fd 48 89 da 48 b8 00 00
RSP: 0018:ffffc90000f2fc98 EFLAGS: 00010293
RAX: 0000000000000000 RBX: ffff8880678e4000 RCX: 0000000000000000
RDX: ffff888011111c00 RSI: ffffffff83bc01c8 RDI: ffff8880183ac590
RBP: 0000607f45e85228 R08: 0000000000000000 R09: ffffffff8ebdd8cf
R10: ffffffff83bc0168 R11: 0000000000000009 R12: ffff8880183ac580
R13: ffff8880678e4000 R14: ffff8880183ac580 R15: ffff888014829c28
FS:  0000000000000000(0000) GS:ffff8880b9e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2dd3a000 CR3: 0000000027fff000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 percpu_ref_exit+0x3b/0x140 lib/percpu-refcount.c:133
 io_ring_ctx_free fs/io_uring.c:8575 [inline]
 io_ring_exit_work+0x49b/0x730 fs/io_uring.c:8637
 process_one_work+0x98d/0x15f0 kernel/workqueue.c:2275
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421
 kthread+0x3b1/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296