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 898990e71367832b15a98a68c48a465d3a034ac3..cc25cbb27e5d8bfeafe216b78e266689539c7d7f 100644 (file)
--- a/io_uring/net.c
+++ b/io_uring/net.c
@@ -1490,9 +1490,11 @@ int io_connect(struct io_kiocb *req, unsigned int issue_flags)
                io = &__io;
        }
 
-       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;
@@ -1524,8 +1526,10 @@ 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 bbdc9a7624a13b52bb218b983cd0c5da9e0ae9f2..ab27a627fd4c62c8e0850f65544fbc5152263737 100644 (file)
--- a/io_uring/poll.c
+++ b/io_uring/poll.c
@@ -288,8 +288,6 @@ static int io_poll_check_events(struct io_kiocb *req, bool *locked)
                                return IOU_POLL_REISSUE;
                        }
                }
-               if (unlikely(req->cqe.res & EPOLLERR))
-                       req_set_fail(req);
                if (req->apoll_events & EPOLLONESHOT)
                        return IOU_POLL_DONE;
                if (io_is_uring_fops(req->file))