From: Christoph Hellwig <hch@infradead.org>
To: "Nicholas A. Bellinger" <nab@linux-iscsi.org>
Cc: target-devel <target-devel@vger.kernel.org>,
linux-scsi <linux-scsi@vger.kernel.org>,
Christoph Hellwig <hch@lst.de>,
stable@vger.kernel.org
Subject: Re: [PATCH] target/iblock: Fix double iblock_complete_cmd callback bug
Date: Thu, 15 Nov 2012 05:49:22 -0500 [thread overview]
Message-ID: <20121115104922.GA28956@infradead.org> (raw)
In-Reply-To: <1352404739-22881-1-git-send-email-nab@linux-iscsi.org>
On Thu, Nov 08, 2012 at 07:58:59PM +0000, Nicholas A. Bellinger wrote:
> From: Nicholas Bellinger <nab@linux-iscsi.org>
>
> This patch fixes a double completion bug where ibr->pending = 2 usage
> plus the extra callback to iblock_complete_cmd() invoked after bio
> submission in iblock_execute_rw() can interfere with the normal
> bio->bi_done() -> iblock_bio_done() -> iblock_complete_cmd() completion
> path, causing a double target_complete_cmd() call to occur.
How so exactly? Please provide an explanation, and preferably a test
case.
> Also drop the bio_cnt >= IBLOCK_MAX_BIO_PER_TASK rolling call to
> iblock_submit_bios() to avoid the exception case where outstanding
> bios completing via iblock_bio_done() are not accounted for when
> returning returning non zero from iblock_execute_rw().
This will cause deadlocks when we can't allocate enough bios for
a too large request.
next prev parent reply other threads:[~2012-11-15 10:49 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-08 19:58 [PATCH] target/iblock: Fix double iblock_complete_cmd callback bug Nicholas A. Bellinger
2012-11-15 10:49 ` Christoph Hellwig [this message]
2012-11-15 22:36 ` Nicholas A. Bellinger
2012-11-15 22:50 ` Nicholas A. Bellinger
2012-11-16 19:25 ` Christoph Hellwig
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=20121115104922.GA28956@infradead.org \
--to=hch@infradead.org \
--cc=hch@lst.de \
--cc=linux-scsi@vger.kernel.org \
--cc=nab@linux-iscsi.org \
--cc=stable@vger.kernel.org \
--cc=target-devel@vger.kernel.org \
/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;
as well as URLs for NNTP newsgroup(s).