The patch titled
Subject: kfence, slab: fix cache_alloc_debugcheck_after() for bulk allocations
has been added to the -mm tree. Its filename is
kfence-slab-fix-cache_alloc_debugcheck_after-for-bulk-allocations.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/kfence-slab-fix-cache_alloc_debugcheck_after-for-bulk-allocations.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/kfence-slab-fix-cache_alloc_debugcheck_after-for-bulk-allocations.patch
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------------------------------------------------------
From: Marco Elver <elver@xxxxxxxxxx>
Subject: kfence, slab: fix cache_alloc_debugcheck_after() for bulk allocations
cache_alloc_debugcheck_after() performs checks on an object, including
adjusting the returned pointer. None of this should apply to KFENCE
objects. While for non-bulk allocations, the checks are skipped when we
allocate via KFENCE, for bulk allocations cache_alloc_debugcheck_after()
is called via cache_alloc_debugcheck_after_bulk().
Fix it by skipping cache_alloc_debugcheck_after() for KFENCE objects.
Link: https://lkml.kernel.org/r/20210304205256.2162309-1-elver@xxxxxxxxxx
Signed-off-by: Marco Elver <elver@xxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Cc: Jann Horn <jannh@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/slab.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/mm/slab.c~kfence-slab-fix-cache_alloc_debugcheck_after-for-bulk-allocations
+++ a/mm/slab.c
@@ -2992,7 +2992,7 @@ static void *cache_alloc_debugcheck_afte
gfp_t flags, void *objp, unsigned long caller)
{
WARN_ON_ONCE(cachep->ctor && (flags & __GFP_ZERO));
- if (!objp)
+ if (!objp || is_kfence_address(objp))
return objp;
if (cachep->flags & SLAB_POISON) {
check_poison_obj(cachep, objp);
_
Patches currently in -mm which might be from elver@xxxxxxxxxx are
kfence-fix-printk-format-for-ptrdiff_t.patch
kfence-slab-fix-cache_alloc_debugcheck_after-for-bulk-allocations.patch
