From: npiggin@suse.de <npiggin@suse.de>
Date: Thu, 24 Jun 2010 03:02:14 +0000 (+1000)
Subject: fs: fix superblock iteration race
X-Git-Tag: v2.6.35-rc4~44
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=57439f878afafefad8836ebf5c49da2a0a746105;p=pandora-kernel.git

fs: fix superblock iteration race

list_for_each_entry_safe is not suitable to protect against concurrent
modification of the list. 6754af6 introduced a race in sb walking.

list_for_each_entry can use the trick of pinning the current entry in
the list before we drop and retake the lock because it subsequently
follows cur->next. However list_for_each_entry_safe saves n=cur->next
for following before entering the loop body, so when the lock is
dropped, n may be deleted.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: John Stultz <johnstul@us.ibm.com>
Cc: Frank Mayhar <fmayhar@google.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

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