From: Eugeniu Rosca <ero...@de.adit-jv.com>
commit dc07a728d49cf025f5da2c31add438d839d076c0 upstream.
Commit 52f23478081ae0 ("mm/slub.c: fix corrupted freechain in
deactivate_slab()") suffered an update when picked up from LKML [1].
Specifically, relocating 'freelist = NULL' into 'freelist_corrupted()'
created a no-op statement. Fix it by sticking to the behavior intended
in the original patch [1]. In addition, make freelist_corrupted()
immune to passing NULL instead of &freelist.
The issue has been spotted via static analysis and code review.
[1]
https://lore.kernel.org/linux-mm/20200331031450.12182-1-dongli.zh...@oracle.com/
Fixes: 52f23478081ae0 ("mm/slub.c: fix corrupted freechain in
deactivate_slab()")
Signed-off-by: Eugeniu Rosca <ero...@de.adit-jv.com>
Signed-off-by: Andrew Morton <a...@linux-foundation.org>
Cc: Dongli Zhang <dongli.zh...@oracle.com>
Cc: Joe Jin <joe....@oracle.com>
Cc: Christoph Lameter <c...@linux.com>
Cc: Pekka Enberg <penb...@kernel.org>
Cc: David Rientjes <rient...@google.com>
Cc: Joonsoo Kim <iamjoonsoo....@lge.com>
Cc: <sta...@vger.kernel.org>
Link: https://lkml.kernel.org/r/20200824130643.10291-1-ero...@de.adit-jv.com
Signed-off-by: Linus Torvalds <torva...@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
mm/slub.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -646,12 +646,12 @@ static void slab_fix(struct kmem_cache *
}
static bool freelist_corrupted(struct kmem_cache *s, struct page *page,
- void *freelist, void *nextfree)
+ void **freelist, void *nextfree)
{
if ((s->flags & SLAB_CONSISTENCY_CHECKS) &&
- !check_valid_pointer(s, page, nextfree)) {
- object_err(s, page, freelist, "Freechain corrupt");
- freelist = NULL;
+ !check_valid_pointer(s, page, nextfree) && freelist) {
+ object_err(s, page, *freelist, "Freechain corrupt");
+ *freelist = NULL;
slab_fix(s, "Isolate corrupted freechain");
return true;
}
@@ -1343,7 +1343,7 @@ static inline void dec_slabs_node(struct
int objects) {}
static bool freelist_corrupted(struct kmem_cache *s, struct page *page,
- void *freelist, void *nextfree)
+ void **freelist, void *nextfree)
{
return false;
}
@@ -2037,7 +2037,7 @@ static void deactivate_slab(struct kmem_
* 'freelist' is already corrupted. So isolate all objects
* starting at 'freelist'.
*/
- if (freelist_corrupted(s, page, freelist, nextfree))
+ if (freelist_corrupted(s, page, &freelist, nextfree))
break;
do {
