kasan: detect invalid frees for large mempool objects
Detect frees of pointers into middle of mempool objects.
I did a one-off test, but it turned out to be very tricky, so I reverted
it. First, mempool does not call kasan_poison_kfree() unless allocation
function fails. I stubbed an allocation function to fail on second and
subsequent allocations. But then mempool stopped to call
kasan_poison_kfree() at all, because it does it only when allocation
function is mempool_kmalloc(). We could support this special failing
test allocation function in mempool, but it also can't live with kasan
tests, because these are in a module.
Link: http://lkml.kernel.org/r/bf7a7d035d7a5ed62d2dd0e3d2e8a4fcdf456aa7.1514378558.git.dvyukov@google.com
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>a
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/mempool.c b/mm/mempool.c
index 7d8c5a0..5c9dce3 100644
--- a/mm/mempool.c
+++ b/mm/mempool.c
@@ -103,10 +103,10 @@
}
#endif /* CONFIG_DEBUG_SLAB || CONFIG_SLUB_DEBUG_ON */
-static void kasan_poison_element(mempool_t *pool, void *element)
+static __always_inline void kasan_poison_element(mempool_t *pool, void *element)
{
if (pool->alloc == mempool_alloc_slab || pool->alloc == mempool_kmalloc)
- kasan_poison_kfree(element);
+ kasan_poison_kfree(element, _RET_IP_);
if (pool->alloc == mempool_alloc_pages)
kasan_free_pages(element, (unsigned long)pool->pool_data);
}
@@ -119,7 +119,7 @@
kasan_alloc_pages(element, (unsigned long)pool->pool_data);
}
-static void add_element(mempool_t *pool, void *element)
+static __always_inline void add_element(mempool_t *pool, void *element)
{
BUG_ON(pool->curr_nr >= pool->min_nr);
poison_element(pool, element);