Re: [PATCH v3] io_uring/poll: fix multishot recv missing EOF on wakeup race

[Jens Axboe <axboe@kernel.dk>]

On 3/17/26 12:37 PM, Pavel Begunkov wrote:
> On 3/17/26 13:07, Jens Axboe wrote:
> ...
>> Right, as per my earlier emails, this is what introduced the issue for
>> AF_UNIX, when the INQ support was added. We read the whole thing, and
>> INQ is correctly returned as having 0 bytes left. Hence no retry
>> happens, and the EOF is missed. We could do something ala the below,
>> entirely untested, which would ensure we retry for that condition.
> 
> static int tcp_inq_hint(struct sock *sk)
> {
>     ...
>     if (inq == 0 && sock_flag(sk, SOCK_DONE))
>         inq = 1;
>     return inq;
> }
> 
> Assuming TCP doesn't work either, I guess I was curious whether it
> gets shutdown but the sock is !SOCK_DONE, or whether inq=1 is correct.
> Just thinking out loud, maybe I will check later.

Ah indeed, yes that's a good find. Let me test that real quick...
I feel like the AF_UNIX inq addition was somewhat half baked.

-- 
Jens Axboe