From: NeilBrown <neilb@suse.de>
Date: Fri, 26 Jan 2007 08:57:11 +0000 (-0800)
Subject: [PATCH] md: fix potential memalloc deadlock in md
X-Git-Tag: v2.6.20-rc7~64
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2a2275d630b982e5f90206f9bc497f6695a3ec5d;p=pandora-kernel.git

[PATCH] md: fix potential memalloc deadlock in md

If a GFP_KERNEL allocation is attempted in md while the mddev_lock is held,
it is possible for a deadlock to eventuate.

This happens if the array was marked 'clean', and the memalloc triggers a
write-out to the md device.

For the writeout to succeed, the array must be marked 'dirty', and that
requires getting the mddev_lock.

So, before attempting a GFP_KERNEL allocation while holding the lock, make
sure the array is marked 'dirty' (unless it is currently read-only).

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

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