From: John Pittman <jpittman@redhat.com>
Date: Mon, 11 Nov 2019 16:43:20 -0800
Subject: [PATCH] md/raid10: prevent access of uninitialized resync_pages
offset
Git-commit: 45422b704db392a6d79d07ee3e3670b11048bd53
Patch-mainline: v5.5
References: bsc#1166003 git-fixes
Due to unneeded multiplication in the out_free_pages portion of
r10buf_pool_alloc(), when using a 3-copy raid10 layout, it is
possible to access a resync_pages offset that has not been
initialized. This access translates into a crash of the system
within resync_free_pages() while passing a bad pointer to
put_page(). Remove the multiplication, preventing access to the
uninitialized area.
Fixes: f0250618361db ("md: raid10: don't use bio's vec table to manage resync pages")
Cc: stable@vger.kernel.org # 4.12+
Signed-off-by: John Pittman <jpittman@redhat.com>
Suggested-by: David Jeffery <djeffery@redhat.com>
Reviewed-by: Laurence Oberman <loberman@redhat.com>
Signed-off-by: Song Liu <songliubraving@fb.com>
Acked-by: NeilBrown <neilb@suse.com>
---
drivers/md/raid10.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -229,7 +229,7 @@ static void * r10buf_pool_alloc(gfp_t gf
out_free_pages:
while (--j >= 0)
- resync_free_pages(&rps[j * 2]);
+ resync_free_pages(&rps[j]);
j = 0;
out_free_bio: