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From: Al Viro <viro@ZenIV.linux.org.uk>
To: Lars Ellenberg <lars.ellenberg@linbit.com>
Cc: Jens Axboe <axboe@kernel.dk>, Richard Weinberger <richard@nod.at>,
	wolfgang.glas@iteg.at, christoph.lechleitner@iteg.at,
	philipp.reisner@linbit.com, stable@vger.kernel.org,
	linux-kernel@vger.kernel.org, drbd-dev@lists.linbit.com
Subject: Re: [PATCH v2] drbd: Fix kernel_sendmsg() usage - potential NULL deref
Date: Wed, 9 Nov 2016 23:41:28 +0000	[thread overview]
Message-ID: <20161109234127.GI19539@ZenIV.linux.org.uk> (raw)
In-Reply-To: <1478728378-22289-1-git-send-email-lars.ellenberg@linbit.com>

On Wed, Nov 09, 2016 at 10:52:58PM +0100, Lars Ellenberg wrote:

> This should go into 4.9,
> and into all stable branches since and including v4.0,
> which is the first to contain the exposing change.
> 
> It is correct for all stable branches older than that as well
> (which contain the DRBD driver; which is 2.6.33 and up).
> 
> It requires a small "conflict" resolution for v4.4 and earlier, with v4.5
> we dropped the comment block immediately preceding the kernel_sendmsg().

ACK.  I'll rebase commit 7a4992299554 ([drbd] use sock_sendmsg()) on top
of that as soon as it hits the mainline.  For conspiracy theorists out
there (hi, Brad) - that commit (killing the modifications of iovec and
reinitializing msg->iov_iter; just set it once and let sendmsg() update
it in normal fashion) had been sitting around since late 2014.  It happened
to fix the bug in question, without a single line refering to that in commit
message.  Reason: I had completely missed the problem; intent of that
loop had been obvious and replacement had obviously done what was intended
there.  What I had failed to spot was that the code in there did *not*
match that intent.  Replacement does.  And unlike the minimal fix (either
version) it doesn't belong in -stable.

  reply	other threads:[~2016-11-09 23:41 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-11-08 13:43 [PATCH] drbd: Fix kernel_sendmsg() usage Lars Ellenberg
2016-11-08 13:55 ` Richard Weinberger
2016-11-08 16:52   ` Jens Axboe
2016-11-09 15:32     ` Lars Ellenberg
2016-11-09 15:47       ` Richard Weinberger
2016-11-09 16:51         ` [Drbd-dev] " Lars Ellenberg
2016-11-09 16:55       ` Jens Axboe
2016-11-09 21:52         ` [PATCH v2] drbd: Fix kernel_sendmsg() usage - potential NULL deref Lars Ellenberg
2016-11-09 23:41           ` Al Viro [this message]
2016-11-08 14:03 ` [PATCH] drbd: Fix kernel_sendmsg() usage Christoph Lechleitner
2016-11-08 15:49 ` Christoph Hellwig
2016-11-08 16:02   ` Richard Weinberger
2016-11-08 16:13   ` Al Viro

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