md/raid10: prevent access of uninitialized resync_pages offset

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: f025061836 ("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>
This commit is contained in:
John Pittman 2019-11-11 16:43:20 -08:00 committed by Song Liu
parent 228fc7d76d
commit 45422b704d

View File

@ -191,7 +191,7 @@ static void * r10buf_pool_alloc(gfp_t gfp_flags, void *data)
out_free_pages:
while (--j >= 0)
resync_free_pages(&rps[j * 2]);
resync_free_pages(&rps[j]);
j = 0;
out_free_bio: