From 1e1132ea21da6d7be92a72195204379c819cb70b Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Thu, 16 Aug 2018 12:23:19 -0400 Subject: [PATCH] dm writecache: fix a crash due to reading past end of dirty_bitmap wc->dirty_bitmap_size is in bytes so must multiply it by 8, not by BITS_PER_LONG, to get number of bitmap_bits. Fixes crash in find_next_bit() that was reported: https://bugzilla.kernel.org/show_bug.cgi?id=200819 Reported-by: edo.rus@gmail.com Fixes: 48debafe4f2f ("dm: add writecache target") Cc: stable@vger.kernel.org # 4.18 Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer --- drivers/md/dm-writecache.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c index e672e1d17bf1..3a28a68f184c 100644 --- a/drivers/md/dm-writecache.c +++ b/drivers/md/dm-writecache.c @@ -457,7 +457,7 @@ static void ssd_commit_flushed(struct dm_writecache *wc) COMPLETION_INITIALIZER_ONSTACK(endio.c), ATOMIC_INIT(1), }; - unsigned bitmap_bits = wc->dirty_bitmap_size * BITS_PER_LONG; + unsigned bitmap_bits = wc->dirty_bitmap_size * 8; unsigned i = 0; while (1) { -- 2.39.5