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-rw-r--r--mm/slub.c52
1 files changed, 29 insertions, 23 deletions
diff --git a/mm/slub.c b/mm/slub.c
index 1bb2a93cf7b6..24f702afd458 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -557,6 +557,26 @@ static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp)
*(freeptr_t *)freeptr_addr = freelist_ptr_encode(s, fp, freeptr_addr);
}
+/*
+ * See comment in calculate_sizes().
+ */
+static inline bool freeptr_outside_object(struct kmem_cache *s)
+{
+ return s->offset >= s->inuse;
+}
+
+/*
+ * Return offset of the end of info block which is inuse + free pointer if
+ * not overlapping with object.
+ */
+static inline unsigned int get_info_end(struct kmem_cache *s)
+{
+ if (freeptr_outside_object(s))
+ return s->inuse + sizeof(void *);
+ else
+ return s->inuse;
+}
+
/* Loop over all objects in a slab */
#define for_each_object(__p, __s, __addr, __objects) \
for (__p = fixup_red_left(__s, __addr); \
@@ -845,26 +865,6 @@ static void print_section(char *level, char *text, u8 *addr,
metadata_access_disable();
}
-/*
- * See comment in calculate_sizes().
- */
-static inline bool freeptr_outside_object(struct kmem_cache *s)
-{
- return s->offset >= s->inuse;
-}
-
-/*
- * Return offset of the end of info block which is inuse + free pointer if
- * not overlapping with object.
- */
-static inline unsigned int get_info_end(struct kmem_cache *s)
-{
- if (freeptr_outside_object(s))
- return s->inuse + sizeof(void *);
- else
- return s->inuse;
-}
-
static struct track *get_track(struct kmem_cache *s, void *object,
enum track_item alloc)
{
@@ -2092,15 +2092,20 @@ bool slab_free_hook(struct kmem_cache *s, void *x, bool init)
*
* The initialization memset's clear the object and the metadata,
* but don't touch the SLAB redzone.
+ *
+ * The object's freepointer is also avoided if stored outside the
+ * object.
*/
if (unlikely(init)) {
int rsize;
+ unsigned int inuse;
+ inuse = get_info_end(s);
if (!kasan_has_integrated_init())
memset(kasan_reset_tag(x), 0, s->object_size);
rsize = (s->flags & SLAB_RED_ZONE) ? s->red_left_pad : 0;
- memset((char *)kasan_reset_tag(x) + s->inuse, 0,
- s->size - s->inuse - rsize);
+ memset((char *)kasan_reset_tag(x) + inuse, 0,
+ s->size - inuse - rsize);
}
/* KASAN might put x into memory quarantine, delaying its reuse. */
return !kasan_slab_free(s, x, init);
@@ -3722,7 +3727,8 @@ static void *__slab_alloc_node(struct kmem_cache *s,
static __always_inline void maybe_wipe_obj_freeptr(struct kmem_cache *s,
void *obj)
{
- if (unlikely(slab_want_init_on_free(s)) && obj)
+ if (unlikely(slab_want_init_on_free(s)) && obj &&
+ !freeptr_outside_object(s))
memset((void *)((char *)kasan_reset_tag(obj) + s->offset),
0, sizeof(void *));
}