linux-kernel - [PATCH] mm-kasan-switch-slub-to-stackdepot-enable-memory-quarantine-for-slub-fix

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Date:	Fri, 15 Jul 2016 19:50:23 +0300
From:	Andrey Ryabinin <aryabinin@...tuozzo.com>
To:	<akpm@...ux-foundation.org>
CC:	<glider@...gle.com>, <dvyukov@...gle.com>,
	<iamjoonsoo.kim@....com>, <kasan-dev@...glegroups.com>,
	<linux-mm@...ck.org>, <linux-kernel@...r.kernel.org>,
	Andrey Ryabinin <aryabinin@...tuozzo.com>
Subject: [PATCH]  mm-kasan-switch-slub-to-stackdepot-enable-memory-quarantine-for-slub-fix

- Remove CONFIG_SLAB ifdefs. The code works just fine with both allocators.
- Reset metada offsets if metadata doesn't fit. Otherwise kasan_metadata_size()
will give us the wrong results.

Signed-off-by: Andrey Ryabinin <aryabinin@...tuozzo.com>
---
 mm/kasan/kasan.c | 17 +++++------------
 1 file changed, 5 insertions(+), 12 deletions(-)

diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c
index d92a7a2..b6f99e8 100644
--- a/mm/kasan/kasan.c
+++ b/mm/kasan/kasan.c
@@ -372,9 +372,7 @@ void kasan_cache_create(struct kmem_cache *cache, size_t *size,
 			unsigned long *flags)
 {
 	int redzone_adjust;
-#ifdef CONFIG_SLAB
 	int orig_size = *size;
-#endif
 
 	/* Add alloc meta. */
 	cache->kasan_info.alloc_meta_offset = *size;
@@ -392,25 +390,20 @@ void kasan_cache_create(struct kmem_cache *cache, size_t *size,
 	if (redzone_adjust > 0)
 		*size += redzone_adjust;
 
-#ifdef CONFIG_SLAB
-	*size = min(KMALLOC_MAX_SIZE,
-		    max(*size,
-			cache->object_size +
-			optimal_redzone(cache->object_size)));
+	*size = min(KMALLOC_MAX_SIZE, max(*size, cache->object_size +
+					optimal_redzone(cache->object_size)));
+
 	/*
 	 * If the metadata doesn't fit, don't enable KASAN at all.
 	 */
 	if (*size <= cache->kasan_info.alloc_meta_offset ||
 			*size <= cache->kasan_info.free_meta_offset) {
+		cache->kasan_info.alloc_meta_offset = 0;
+		cache->kasan_info.free_meta_offset = 0;
 		*size = orig_size;
 		return;
 	}
-#else
-	*size = max(*size,
-			cache->object_size +
-			optimal_redzone(cache->object_size));
 
-#endif
 	*flags |= SLAB_KASAN;
 }
 
-- 
2.7.3