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

[Pavel Begunkov <asml.silence@gmail.com>]

On 7/14/25 15:56, Jens Axboe wrote:
> 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?

good point, shouldn't be here

-- 
Pavel Begunkov