Re: [PATCH 1/1] io_uring/poll: fix POLLERR handling

[Jens Axboe <axboe@kernel.dk>]

On 7/14/25 4:59 AM, Pavel Begunkov wrote:
> 8c8492ca64e7 ("io_uring/net: don't retry connect operation on EPOLLERR")
> is a little dirty hack that
> 1) wrongfully assumes that POLLERR equals to a failed request, which
> breaks all POLLERR users, e.g. all error queue recv interfaces.
> 2) deviates the connection request behaviour from connect(2), and
> 3) racy and solved at a wrong level.
> 
> Nothing can be done with 2) now, and 3) is beyond the scope of the
> patch. At least solve 1) by moving the hack out of generic poll handling
> into io_connect().
> 
> Cc: stable@vger.kernel.org
> Fixes: 8c8492ca64e79 ("io_uring/net: don't retry connect operation on EPOLLERR")
> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
> ---
>  io_uring/net.c  | 4 +++-
>  io_uring/poll.c | 2 --
>  2 files changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/io_uring/net.c b/io_uring/net.c
> index 43a43522f406..e2213e4d9420 100644
> --- a/io_uring/net.c
> +++ b/io_uring/net.c
> @@ -1732,13 +1732,15 @@ int io_connect_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
>  
>  int io_connect(struct io_kiocb *req, unsigned int issue_flags)
>  {
> +	struct poll_table_struct pt = { ._key = EPOLLERR };
>  	struct io_connect *connect = io_kiocb_to_cmd(req, struct io_connect);
>  	struct io_async_msghdr *io = req->async_data;
>  	unsigned file_flags;
>  	int ret;
>  	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
>  
> -	if (unlikely(req->flags & REQ_F_FAIL)) {
> +	ret = vfs_poll(req->file, &pt) & req->apoll_events;
> +	if (ret & EPOLLERR) {
>  		ret = -ECONNRESET;
>  		goto out;

Is this req->apoll_events masking necessary or useful?

-- 
Jens Axboe