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Subject[PATCH] mm/mempool: Avoid KASAN marking mempool posion checks as use-after-free
Date
When removing an element from the mempool, mark it as unpoisoned in KASAN
before verifying its contents for SLUB/SLAB debugging. Otherwise KASAN
will flag the reads checking the element use-after-free writes as
use-after-free reads.

Signed-off-by: Matthew Dawson <matthew@mjdsystems.ca>
---
mm/mempool.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/mempool.c b/mm/mempool.c
index 004d42b..7924f4f 100644
--- a/mm/mempool.c
+++ b/mm/mempool.c
@@ -135,8 +135,8 @@ static void *remove_element(mempool_t *pool)
void *element = pool->elements[--pool->curr_nr];

BUG_ON(pool->curr_nr < 0);
- check_element(pool, element);
kasan_unpoison_element(pool, element);
+ check_element(pool, element);
return element;
}

--
2.7.1
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