public inbox for [email protected]
 help / color / mirror / Atom feed
From: Pavel Begunkov <[email protected]>
To: [email protected]
Cc: Jens Axboe <[email protected]>,
	[email protected], Beld Zhang <[email protected]>
Subject: [PATCH for-next 1/2] io_uring/rw: fix unexpected link breakage
Date: Tue, 27 Sep 2022 00:20:28 +0100	[thread overview]
Message-ID: <e249fd61212bf9d1b15dbd4628a4ba615c5eef51.1664234240.git.asml.silence@gmail.com> (raw)
In-Reply-To: <[email protected]>

req->cqe.res is set in io_read() to the amount of bytes left to be done,
which is used to figure out whether to fail a read or not. However,
io_read() may do another without returning, and we stash the previous
value into ->bytes_done but forget to update cqe.res. Then we ask a read
to do strictly less than cqe.res but expect the return to be exactly
cqe.res.

Fix the bug by updating cqe.res for retries.

Cc: [email protected]
Reported-by: Beld Zhang <[email protected]>
Signed-off-by: Pavel Begunkov <[email protected]>
---
 io_uring/rw.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/io_uring/rw.c b/io_uring/rw.c
index 76ebcfebc9a6..c562203d7a67 100644
--- a/io_uring/rw.c
+++ b/io_uring/rw.c
@@ -823,6 +823,7 @@ int io_read(struct io_kiocb *req, unsigned int issue_flags)
 			return -EAGAIN;
 		}
 
+		req->cqe.res = iov_iter_count(&s->iter);
 		/*
 		 * Now retry read with the IOCB_WAITQ parts set in the iocb. If
 		 * we get -EIOCBQUEUED, then we'll get a notification when the
-- 
2.37.2


  reply	other threads:[~2022-09-26 23:23 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-26 23:20 [PATCH for-next 0/2] rw link fixes Pavel Begunkov
2022-09-26 23:20 ` Pavel Begunkov [this message]
2022-09-26 23:20 ` [PATCH for-next 2/2] io_uring/rw: don't lose short results on io_setup_async_rw() Pavel Begunkov
2022-09-27  0:43 ` [PATCH for-next 0/2] rw link fixes Jens Axboe
2022-09-27  0:45   ` Jens Axboe

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=e249fd61212bf9d1b15dbd4628a4ba615c5eef51.1664234240.git.asml.silence@gmail.com \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox