From df3ae2c9941d38106afd67d7816b58f6dc7405e8 Mon Sep 17 00:00:00 2001
From: Marco Elver <elver@google.com>
Date: Fri, 12 Mar 2021 21:07:53 -0800
Subject: [PATCH] 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@google.com
Signed-off-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Jann Horn <jannh@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
mm/slab.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/slab.c b/mm/slab.c
index 51fd424e0d6d0..ae651bf540b70 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -2992,7 +2992,7 @@ static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep,
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);
--
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