From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg KH Subject: [patch 19/20] MD: Fix a potential NULL dereference in md/raid1 Date: Mon, 21 Aug 2006 11:48:24 -0700 Message-ID: <20060821184824.GU21938@kroah.com> References: <20060821183818.155091391@quad.kroah.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline; filename="md-fix-a-potential-null-dereference-in-md-raid1.patch" In-Reply-To: <20060821184527.GA21938@kroah.com> Sender: linux-raid-owner@vger.kernel.org To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: Justin Forbes , Zwane Mwaikambo , Theodore Ts'o , Randy Dunlap , Dave Jones , Chuck Wolber , Chris Wedgwood , torvalds@osdl.org, akpm@osdl.org, alan@lxorguk.ukuu.org.uk, linux-raid@vger.kernel.org, Neil Brown , Greg Kroah-Hartman List-Id: linux-raid.ids -stable review patch. If anyone has any objections, please let us know. ------------------ From: NeilBrown At the point where this 'atomic_add' is, rdev could be NULL, as seen by the fact that we test for this in the very next statement. Further is it is really the wrong place of the add. We could add to the count of corrected errors once the are sure it was corrected, not before trying to correct it. Signed-off-by: Neil Brown Signed-off-by: Greg Kroah-Hartman diff .prev/drivers/md/raid1.c ./drivers/md/raid1.c --- drivers/md/raid1.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- linux-2.6.17.9.orig/drivers/md/raid1.c +++ linux-2.6.17.9/drivers/md/raid1.c @@ -1486,7 +1486,6 @@ static void raid1d(mddev_t *mddev) d = conf->raid_disks; d--; rdev = conf->mirrors[d].rdev; - atomic_add(s, &rdev->corrected_errors); if (rdev && test_bit(In_sync, &rdev->flags)) { if (sync_page_io(rdev->bdev, @@ -1509,6 +1508,9 @@ static void raid1d(mddev_t *mddev) s<<9, conf->tmppage, READ) == 0) /* Well, this device is dead */ md_error(mddev, rdev); + else + atomic_add(s, &rdev->corrected_errors); + } } } else { --