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mm: slub: fix conversion of freelist_corrupted() 

Commit 52f2347808 ("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: 52f2347808 ("mm/slub.c: fix corrupted freechain in deactivate_slab()")
Signed-off-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Signed-off-by: Andrew 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.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
zero-sugar-mainline-defconfig
Eugeniu Rosca 2020-09-04 16:35:30 -07:00 committed by Linus Torvalds
parent e3336cab25
commit dc07a728d4
1 changed files with 6 additions and 6 deletions
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12
mm/slub.c
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@ -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, 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) && if ((s->flags & SLAB_CONSISTENCY_CHECKS) &&
!check_valid_pointer(s, page, nextfree)) { !check_valid_pointer(s, page, nextfree) && freelist) {
object_err(s, page, freelist, "Freechain corrupt"); object_err(s, page, *freelist, "Freechain corrupt");
freelist = NULL; *freelist = NULL;
slab_fix(s, "Isolate corrupted freechain"); slab_fix(s, "Isolate corrupted freechain");
return true; return true;
} }
@ -1494,7 +1494,7 @@ static inline void dec_slabs_node(struct kmem_cache *s, int node,
int objects) {} int objects) {}
static bool freelist_corrupted(struct kmem_cache *s, struct page *page, static bool freelist_corrupted(struct kmem_cache *s, struct page *page,
void *freelist, void *nextfree) void **freelist, void *nextfree)
{ {
return false; 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 * 'freelist' is already corrupted. So isolate all objects
* starting at 'freelist'. * starting at 'freelist'.
*/ */
if (freelist_corrupted(s, page, freelist, nextfree)) if (freelist_corrupted(s, page, &freelist, nextfree))
break; break;
do { do {