From: Paul Clements <Paul.Clements@SteelEye.com>
To: Lou Langholtz <ldl@aros.net>
Cc: linux-kernel <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@osdl.org>
Subject: Re: [PATCH] 2.6.0 NBD driver: remove send/recieve race for request
Date: Tue, 05 Aug 2003 15:37:04 -0400 [thread overview]
Message-ID: <3F300760.8F703814@SteelEye.com> (raw)
In-Reply-To: 3F2FE078.6020305@aros.net
Lou Langholtz wrote:
>
> The following patch removes a race condition in the network block device
> driver in 2.6.0*. Without this patch, the reply receiving thread could
> end (and free up the memory for) the request structure before the
> request sending thread is completely done accessing it and would then
> access invalid memory.
Indeed, there is a race condition here. It's a very small window, but it
looks like it could possibly be trouble on SMP/preempt kernels.
This patch looks OK, but it appears to still leave the race window open
in the error case (it seems to fix the non-error case, though). We
probably could actually use the ref_count field of struct request to
better fix this problem. I'll take a look at doing this, and send a
patch out in a while.
Thanks,
Paul
next prev parent reply other threads:[~2003-08-05 19:39 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-08-05 16:51 [PATCH] 2.6.0 NBD driver: remove send/recieve race for request Lou Langholtz
2003-08-05 19:37 ` Paul Clements [this message]
2003-08-05 22:48 ` Lou Langholtz
2003-08-06 0:51 ` Paul Clements
2003-08-06 7:34 ` Lou Langholtz
2003-08-08 5:02 ` Paul Clements
2003-08-08 5:27 ` Andrew Morton
2003-08-08 17:05 ` Paul Clements
2003-08-08 6:30 ` Lou Langholtz
2003-08-08 6:43 ` Andrew Morton
2003-08-08 6:59 ` Jens Axboe
2003-08-08 15:00 ` Paul Clements
2003-08-25 9:58 ` Jens Axboe
2003-08-08 16:47 ` Paul Clements
2003-08-08 20:07 ` [PATCH 2.6.0-test2-mm] nbd: fix send/receive/shutdown/disconnect races Paul Clements
2003-08-09 22:10 ` [PATCH 2.4.22-pre] nbd: fix race conditions Paul Clements
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=3F300760.8F703814@SteelEye.com \
--to=paul.clements@steeleye.com \
--cc=akpm@osdl.org \
--cc=ldl@aros.net \
--cc=linux-kernel@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).