diff mbox series

[mm,v2,01/33] kasan: check KASAN_NO_FREE_META in __kasan_metadata_size

Message ID e4a075c43dc6793253976780311543fefd82cba3.1658189199.git.andreyknvl@google.com (mailing list archive)
State New
Headers show
Series kasan: switch tag-based modes to stack ring from per-object metadata | expand

Commit Message

andrey.konovalov@linux.dev July 19, 2022, 12:09 a.m. UTC 
From: Andrey Konovalov <andreyknvl@google.com>

__kasan_metadata_size() calculates the size of the redzone for objects
in a slab cache.

When accounting for presence of kasan_free_meta in the redzone, this
function only compares free_meta_offset with 0. But free_meta_offset could
also be equal to KASAN_NO_FREE_META, which indicates that kasan_free_meta
is not present at all.

Add a comparison with KASAN_NO_FREE_META into __kasan_metadata_size().

Reviewed-by: Marco Elver <elver@google.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>

---

This is a minor fix that only affects slub_debug runs, so it is probably
not worth backporting.
---
 mm/kasan/common.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/mm/kasan/common.c b/mm/kasan/common.c
index 707c3a527fcb..b7351b860abf 100644
--- a/mm/kasan/common.c
+++ b/mm/kasan/common.c
@@ -223,8 +223,9 @@  size_t __kasan_metadata_size(struct kmem_cache *cache)
 		return 0;
 	return (cache->kasan_info.alloc_meta_offset ?
 		sizeof(struct kasan_alloc_meta) : 0) +
-		(cache->kasan_info.free_meta_offset ?
-		sizeof(struct kasan_free_meta) : 0);
+		((cache->kasan_info.free_meta_offset &&
+		  cache->kasan_info.free_meta_offset != KASAN_NO_FREE_META) ?
+		 sizeof(struct kasan_free_meta) : 0);
 }
 
 struct kasan_alloc_meta *kasan_get_alloc_meta(struct kmem_cache *cache,