From: NeilBrown Date: Mon, 21 May 2007 01:33:03 +0000 (+1000) Subject: [PATCH] md: Avoid overflow in raid0 calculation with large components. X-Git-Tag: v2.6.20.16~26 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=cb9072a6c6322f4615576537b024a42252b7ac15;p=thirdparty%2Fkernel%2Fstable.git [PATCH] md: Avoid overflow in raid0 calculation with large components. If a raid0 has a component device larger than 4TB, and is accessed on a 32bit machines, then as 'chunk' is unsigned lock, chunk << chunksize_bits can overflow (this can be as high as the size of the device in KB). chunk itself will not overflow (without triggering a BUG). So change 'chunk' to be 'sector_t, and get rid of the 'BUG' as it becomes impossible to hit. Cc: "Jeff Zheng" Signed-off-by: Neil Brown Signed-off-by: Chris Wright Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c index dfe32149ad3ae..2c404f73a377d 100644 --- a/drivers/md/raid0.c +++ b/drivers/md/raid0.c @@ -415,7 +415,7 @@ static int raid0_make_request (request_queue_t *q, struct bio *bio) raid0_conf_t *conf = mddev_to_conf(mddev); struct strip_zone *zone; mdk_rdev_t *tmp_dev; - unsigned long chunk; + sector_t chunk; sector_t block, rsect; const int rw = bio_data_dir(bio); @@ -470,7 +470,6 @@ static int raid0_make_request (request_queue_t *q, struct bio *bio) sector_div(x, zone->nb_dev); chunk = x; - BUG_ON(x != (sector_t)chunk); x = block >> chunksize_bits; tmp_dev = zone->dev[sector_div(x, zone->nb_dev)];