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From:   andrey.konovalov@linux.dev
To:     Marco Elver <elver@google.com>,
        Alexander Potapenko <glider@google.com>
Cc:     Andrey Konovalov <andreyknvl@gmail.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Andrey Ryabinin <ryabinin.a.a@gmail.com>,
        kasan-dev@googlegroups.com, Evgenii Stepanov <eugenis@google.com>,
        Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org,
        Andrey Konovalov <andreyknvl@google.com>
Subject: [PATCH RFC 13/20] mempool: use new mempool KASAN hooks
Date:   Mon,  6 Nov 2023 21:10:22 +0100
Message-Id: <35771e9e5fc0fe2169c59f190fbd6bfc901b7c09.1699297309.git.andreyknvl@google.com>
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From: Andrey Konovalov <andreyknvl@google.com>

Update the mempool code to use the new mempool KASAN hooks.

Rely on the return value of kasan_mempool_poison_object and
kasan_mempool_poison_pages to prevent double-free and invalid-free bugs.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 mm/mempool.c | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/mm/mempool.c b/mm/mempool.c
index 768cb39dc5e2..f67ca6753332 100644
--- a/mm/mempool.c
+++ b/mm/mempool.c
@@ -104,32 +104,34 @@ static inline void poison_element(mempool_t *pool, void *element)
 }
 #endif /* CONFIG_DEBUG_SLAB || CONFIG_SLUB_DEBUG_ON */
 
-static __always_inline void kasan_poison_element(mempool_t *pool, void *element)
+static __always_inline bool kasan_poison_element(mempool_t *pool, void *element)
 {
 	if (pool->alloc == mempool_alloc_slab || pool->alloc == mempool_kmalloc)
-		kasan_mempool_poison_object(element);
+		return kasan_mempool_poison_object(element);
 	else if (pool->alloc == mempool_alloc_pages)
-		kasan_poison_pages(element, (unsigned long)pool->pool_data,
-				   false);
+		return kasan_mempool_poison_pages(element,
+						(unsigned long)pool->pool_data);
+	return true;
 }
 
 static void kasan_unpoison_element(mempool_t *pool, void *element)
 {
 	if (pool->alloc == mempool_kmalloc)
-		kasan_unpoison_range(element, (size_t)pool->pool_data);
+		kasan_mempool_unpoison_object(element, (size_t)pool->pool_data);
 	else if (pool->alloc == mempool_alloc_slab)
-		kasan_unpoison_range(element, kmem_cache_size(pool->pool_data));
+		kasan_mempool_unpoison_object(element,
+					      kmem_cache_size(pool->pool_data));
 	else if (pool->alloc == mempool_alloc_pages)
-		kasan_unpoison_pages(element, (unsigned long)pool->pool_data,
-				     false);
+		kasan_mempool_unpoison_pages(element,
+					     (unsigned long)pool->pool_data);
 }
 
 static __always_inline void add_element(mempool_t *pool, void *element)
 {
 	BUG_ON(pool->curr_nr >= pool->min_nr);
 	poison_element(pool, element);
-	kasan_poison_element(pool, element);
-	pool->elements[pool->curr_nr++] = element;
+	if (kasan_poison_element(pool, element))
+		pool->elements[pool->curr_nr++] = element;
 }
 
 static void *remove_element(mempool_t *pool)
-- 
2.25.1