Commit dc07a728 authored by Eugeniu Rosca's avatar Eugeniu Rosca Committed by Linus Torvalds

mm: slub: fix conversion of freelist_corrupted()

Commit 52f23478 ("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.zhang@oracle.com/

Fixes: 52f23478 ("mm/slub.c: fix corrupted freechain in deactivate_slab()")
Signed-off-by: default avatarEugeniu Rosca <erosca@de.adit-jv.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Cc: Dongli Zhang <dongli.zhang@oracle.com>
Cc: Joe Jin <joe.jin@oracle.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20200824130643.10291-1-erosca@de.adit-jv.comSigned-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e3336cab
......@@ -672,12 +672,12 @@ static void slab_fix(struct kmem_cache *s, char *fmt, ...)
}
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;
}
......@@ -1494,7 +1494,7 @@ static inline void dec_slabs_node(struct kmem_cache *s, int node,
int objects) {}
static bool freelist_corrupted(struct kmem_cache *s, struct page *page,
void *freelist, void *nextfree)
void **freelist, void *nextfree)
{
return false;
}
......@@ -2184,7 +2184,7 @@ static void deactivate_slab(struct kmem_cache *s, struct page *page,
* '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 {
......
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