From: Pavel Begunkov <[email protected]>
To: Joseph Qi <[email protected]>,
Jens Axboe <[email protected]>,
[email protected]
Subject: Re: [PATCH 5.11] io_uring: fix wqe->lock/completion_lock deadlock
Date: Wed, 27 Jan 2021 09:21:30 +0000 [thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
On 27/01/2021 01:52, Joseph Qi wrote:>> Only __io_queue_deferred() calls queue_async_work() while holding
>> ctx->completion_lock, enqueue drained requests via io_req_task_queue()
>> instead.
>>
> We should follow &wqe->lock > &ctx->completion_lock from now on, right?
> I was thinking getting completion_lock first before:(
>
> Moreover, there are so many locks and no suggested locking order in
> comments, so that it is hard for us to participate in the work.
It's rc5, so that was rather of a "make it fast" kind... I don't like
this ordering, but hopefully the patch doesn't enforce it, and I'd leave
it for 5.11 and prefer to see something else for next releases.
Would be glad to review if take on it. I think it's no good taking a
lock before io_wq_cancel_cb(), but there should be other options. E.g.
split wqe->lock in two.
>
>> Cc: [email protected] # 5.9+
>> Reported-by: Joseph Qi <[email protected]>
>
> Tested-by: Joseph Qi <[email protected]>
Thanks!
--
Pavel Begunkov
prev parent reply other threads:[~2021-01-27 9:31 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-26 23:35 [PATCH 5.11] io_uring: fix wqe->lock/completion_lock deadlock Pavel Begunkov
2021-01-26 23:37 ` Pavel Begunkov
2021-01-27 1:52 ` Joseph Qi
2021-01-27 2:40 ` Jens Axboe
2021-01-27 9:21 ` Pavel Begunkov [this message]
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 \
[email protected] \
[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