Dear Linux kernel maintainers,

Syzkaller reports this previously unknown bug on Linux
6.8.0-rc3-00043-ga69d20885494-dirty #4. Seems like the bug was
silently or unintendedly fixed in the latest version.

```
Syzkaller hit 'WARNING in io_fill_cqe_req_aux' bug.

------------[ cut here ]------------
WARNING: CPU: 7 PID: 8369 at io_uring/io_uring.h:132
io_lockdep_assert_cq_locked+0x2c7/0x340 io_uring/io_uring.h:132
Modules linked in:
CPU: 7 PID: 8369 Comm: syz-executor263 Not tainted
6.8.0-rc3-00043-ga69d20885494-dirty #4
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
RIP: 0010:io_lockdep_assert_cq_locked+0x2c7/0x340 io_uring/io_uring.h:132
Code: 48 8d bb 98 03 00 00 be ff ff ff ff e8 52 45 4b 06 31 ff 89 c3
89 c6 e8 b7 e2 2d fd 85 db 0f 85 d5 fe ff ff e8 0a e7 2d fd 90 <0f> 0b
90 e9 c7 fe ff ff e8 fc e6 2d fd e8 c7 38 fa fc 48 85 c0 0f
RSP: 0018:ffffc90012af79a8 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff845cf059
RDX: ffff8880252ea440 RSI: ffffffff845cf066 RDI: 0000000000000005
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000001
FS:  00005555570e13c0(0000) GS:ffff88823bd80000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1bdbcae020 CR3: 0000000022624000 CR4: 0000000000750ef0
PKRU: 55555554
Call Trace:
 <TASK>
 io_fill_cqe_req_aux+0xd6/0x1f0 io_uring/io_uring.c:925
 io_poll_check_events io_uring/poll.c:325 [inline]
 io_poll_task_func+0x16f/0x1000 io_uring/poll.c:357
 io_handle_tw_list+0x172/0x560 io_uring/io_uring.c:1154
 tctx_task_work_run+0xaa/0x330 io_uring/io_uring.c:1226
 tctx_task_work+0x7b/0xd0 io_uring/io_uring.c:1244
 task_work_run+0x16d/0x260 kernel/task_work.c:180
 get_signal+0x1cb/0x25a0 kernel/signal.c:2669
 arch_do_signal_or_restart+0x81/0x7e0 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop kernel/entry/common.c:105 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:201 [inline]
 syscall_exit_to_user_mode+0x156/0x2b0 kernel/entry/common.c:212
 do_syscall_64+0xe5/0x270 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x6f/0x77
RIP: 0033:0x7f1bdbc2d88d
Code: c3 e8 a7 1f 00 00 0f 1f 80 00 00 00 00 f3 0f 1e fa 48 89 f8 48
89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d
01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd12f6fa18 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa
RAX: 0000000000000001 RBX: 000000000000220b RCX: 00007f1bdbc2d88d
RDX: 0000000000000000 RSI: 0000000000005012 RDI: 0000000000000003
RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 431bde82d7b634db R14: 00007f1bdbcaa4f0 R15: 0000000000000001
 </TASK>


Syzkaller reproducer:
# {Threaded:false Repeat:true RepeatTimes:0 Procs:1 Slowdown:1
Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false
NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false
KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false
Wifi:false IEEE802154:false Sysctl:false Swap:false UseTmpDir:false
HandleSegv:false Repro:false Trace:false LegacyOptions:{Collide:false
Fault:false FaultCall:0 FaultNth:0}}
r0 = syz_io_uring_setup(0x220b, &(0x7f0000000000)={0x0, 0x63db,
0x10000, 0x800}, &(0x7f0000000080)=<r1=>0x0,
&(0x7f0000000200)=<r2=>0x0)
r3 = socket$inet(0x2, 0x1, 0x0)
syz_io_uring_submit(r1, r2,
&(0x7f0000000a80)=@IORING_OP_POLL_ADD={0x6, 0x0, 0x0, @fd=r3, 0x0,
0x0, 0x1})
io_uring_enter(r0, 0x5012, 0x0, 0x0, 0x0, 0x0)
```

crepro is in the attachment.

Best Regards
Xdchase