io_uring/poll: fix POLLERR handling

commit c7cafd5b81cc07fb402e3068d134c21e60ea688c upstream.

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>
Link: https://lore.kernel.org/r/3dc89036388d602ebd84c28e5042e457bdfc952b.1752682444.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/io_uring/net.c b/io_uring/net.c
index 7bf5e62d5a292e1302cc54793ad2205ac6c3adf7..4dac01ff7ac77266d387c0dab0fff4094bc04de3 100644 (file)
--- a/io_uring/net.c
+++ b/io_uring/net.c
@@ -1749,9 +1749,11 @@ int io_connect(struct io_kiocb *req, unsigned int issue_flags)
        int ret;
        bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
 
-       if (unlikely(req->flags & REQ_F_FAIL)) {
-               ret = -ECONNRESET;
-               goto out;
+       if (connect->in_progress) {
+               struct poll_table_struct pt = { ._key = EPOLLERR };
+
+               if (vfs_poll(req->file, &pt) & EPOLLERR)
+                       goto get_sock_err;
        }
 
        file_flags = force_nonblock ? O_NONBLOCK : 0;
@@ -1776,8 +1778,10 @@ int io_connect(struct io_kiocb *req, unsigned int issue_flags)
                 * which means the previous result is good. For both of these,
                 * grab the sock_error() and use that for the completion.
                 */
-               if (ret == -EBADFD || ret == -EISCONN)
+               if (ret == -EBADFD || ret == -EISCONN) {
+get_sock_err:
                        ret = sock_error(sock_from_file(req->file)->sk);
+               }
        }
        if (ret == -ERESTARTSYS)
                ret = -EINTR;

diff --git a/io_uring/poll.c b/io_uring/poll.c
index 8eb744eb9f4c3c41bc5d40154f81229eb35007d2..ddafa88b9fbedac438f06fbf253e7c7f846fc04f 100644 (file)
--- a/io_uring/poll.c
+++ b/io_uring/poll.c
@@ -273,8 +273,6 @@ static int io_poll_check_events(struct io_kiocb *req, io_tw_token_t tw)
                                return IOU_POLL_REISSUE;
                        }
                }
-               if (unlikely(req->cqe.res & EPOLLERR))
-                       req_set_fail(req);
                if (req->apoll_events & EPOLLONESHOT)
                        return IOU_POLL_DONE;