From 7571ae887d3b96d8e7ce63d43828866c6a91cdc6 Mon Sep 17 00:00:00 2001 From: NeilBrown <neilb@suse.de> Date: Thu, 7 Oct 2010 11:54:46 +1100 Subject: md/raid1: avoid overflow in raid1 resync when bitmap is in use. bitmap_start_sync returns - via a pass-by-reference variable - the number of sectors before we need to check with the bitmap again. Since commit ef4256733506f245 this number can be substantially larger, 2^27 is a common value. Unfortunately it is an 'int' and so when raid1.c:sync_request shifts it 9 places to the left it becomes 0. This results in a zero-length read which the scsi layer justifiably complains about. This patch just removes the shift so the common case becomes safe with a trivially-correct patch. In the next merge window we will convert this 'int' to a 'sector_t' Reported-by: "George Spelvin" <linux@horizon.com> Signed-off-by: NeilBrown <neilb@suse.de> --- drivers/md/raid1.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/md/raid1.c') diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c index ad83a4d..fba4d2f 100644 --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -1912,7 +1912,7 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) break; BUG_ON(sync_blocks < (PAGE_SIZE>>9)); - if (len > (sync_blocks<<9)) + if ((len >> 9) > sync_blocks) len = sync_blocks<<9; } -- cgit v1.1