1 files changed, 67 insertions, 18 deletions

diff --git a/mm/slub.c b/mm/slub.c
index a0c1365f6426..d52f0d0ab712 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1065,11 +1065,15 @@ bad:
 	return 0;
 }
 
+/* Supports checking bulk free of a constructed freelist */
 static noinline struct kmem_cache_node *free_debug_processing(
-	struct kmem_cache *s, struct page *page, void *object,
+	struct kmem_cache *s, struct page *page,
+	void *head, void *tail, int bulk_cnt,
 	unsigned long addr, unsigned long *flags)
 {
 	struct kmem_cache_node *n = get_node(s, page_to_nid(page));
+	void *object = head;
+	int cnt = 0;
 
 	spin_lock_irqsave(&n->list_lock, *flags);
 	slab_lock(page);
@@ -1077,6 +1081,9 @@ static noinline struct kmem_cache_node *free_debug_processing(
 	if (!check_slab(s, page))
 		goto fail;
 
+next_object:
+	cnt++;
+
 	if (!check_valid_pointer(s, page, object)) {
 		slab_err(s, page, "Invalid object pointer 0x%p", object);
 		goto fail;
@@ -1107,8 +1114,19 @@ static noinline struct kmem_cache_node *free_debug_processing(
 	if (s->flags & SLAB_STORE_USER)
 		set_track(s, object, TRACK_FREE, addr);
 	trace(s, page, object, 0);
+	/* Freepointer not overwritten by init_object(), SLAB_POISON moved it */
 	init_object(s, object, SLUB_RED_INACTIVE);
+
+	/* Reached end of constructed freelist yet? */
+	if (object != tail) {
+		object = get_freepointer(s, object);
+		goto next_object;
+	}
 out:
+	if (cnt != bulk_cnt)
+		slab_err(s, page, "Bulk freelist count(%d) invalid(%d)\n",
+			 bulk_cnt, cnt);
+
 	slab_unlock(page);
 	/*
 	 * Keep node_lock to preserve integrity
@@ -1212,7 +1230,8 @@ static inline int alloc_debug_processing(struct kmem_cache *s,
 	struct page *page, void *object, unsigned long addr) { return 0; }
 
 static inline struct kmem_cache_node *free_debug_processing(
-	struct kmem_cache *s, struct page *page, void *object,
+	struct kmem_cache *s, struct page *page,
+	void *head, void *tail, int bulk_cnt,
 	unsigned long addr, unsigned long *flags) { return NULL; }
 
 static inline int slab_pad_check(struct kmem_cache *s, struct page *page)
@@ -1308,6 +1327,29 @@ static inline void slab_free_hook(struct kmem_cache *s, void *x)
 	kasan_slab_free(s, x);
 }
 
+static inline void slab_free_freelist_hook(struct kmem_cache *s,
+					   void *head, void *tail)
+{
+/*
+ * Compiler cannot detect this function can be removed if slab_free_hook()
+ * evaluates to nothing.  Thus, catch all relevant config debug options here.
+ */
+#if defined(CONFIG_KMEMCHECK) ||		\
+	defined(CONFIG_LOCKDEP)	||		\
+	defined(CONFIG_DEBUG_KMEMLEAK) ||	\
+	defined(CONFIG_DEBUG_OBJECTS_FREE) ||	\
+	defined(CONFIG_KASAN)
+
+	void *object = head;
+	void *tail_obj = tail ? : head;
+
+	do {
+		slab_free_hook(s, object);
+	} while ((object != tail_obj) &&
+		 (object = get_freepointer(s, object)));
+#endif
+}
+
 static void setup_object(struct kmem_cache *s, struct page *page,
 				void *object)
 {
@@ -2583,10 +2625,11 @@ EXPORT_SYMBOL(kmem_cache_alloc_node_trace);
  * handling required then we can return immediately.
  */
 static void __slab_free(struct kmem_cache *s, struct page *page,
-			void *x, unsigned long addr)
+			void *head, void *tail, int cnt,
+			unsigned long addr)
+
 {
 	void *prior;
-	void **object = (void *)x;
 	int was_frozen;
 	struct page new;
 	unsigned long counters;
@@ -2596,7 +2639,8 @@ static void __slab_free(struct kmem_cache *s, struct page *page,
 	stat(s, FREE_SLOWPATH);
 
 	if (kmem_cache_debug(s) &&
-		!(n = free_debug_processing(s, page, x, addr, &flags)))
+	    !(n = free_debug_processing(s, page, head, tail, cnt,
+					addr, &flags)))
 		return;
 
 	do {
@@ -2606,10 +2650,10 @@ static void __slab_free(struct kmem_cache *s, struct page *page,
 		}
 		prior = page->freelist;
 		counters = page->counters;
-		set_freepointer(s, object, prior);
+		set_freepointer(s, tail, prior);
 		new.counters = counters;
 		was_frozen = new.frozen;
-		new.inuse--;
+		new.inuse -= cnt;
 		if ((!new.inuse || !prior) && !was_frozen) {
 
 			if (kmem_cache_has_cpu_partial(s) && !prior) {
@@ -2640,7 +2684,7 @@ static void __slab_free(struct kmem_cache *s, struct page *page,
 
 	} while (!cmpxchg_double_slab(s, page,
 		prior, counters,
-		object, new.counters,
+		head, new.counters,
 		"__slab_free"));
 
 	if (likely(!n)) {
@@ -2705,15 +2749,20 @@ slab_empty:
  *
  * If fastpath is not possible then fall back to __slab_free where we deal
  * with all sorts of special processing.
+ *
+ * Bulk free of a freelist with several objects (all pointing to the
+ * same page) possible by specifying head and tail ptr, plus objects
+ * count (cnt). Bulk free indicated by tail pointer being set.
  */
-static __always_inline void slab_free(struct kmem_cache *s,
-			struct page *page, void *x, unsigned long addr)
+static __always_inline void slab_free(struct kmem_cache *s, struct page *page,
+				      void *head, void *tail, int cnt,
+				      unsigned long addr)
 {
-	void **object = (void *)x;
+	void *tail_obj = tail ? : head;
 	struct kmem_cache_cpu *c;
 	unsigned long tid;
 
-	slab_free_hook(s, x);
+	slab_free_freelist_hook(s, head, tail);
 
 redo:
 	/*
@@ -2732,19 +2781,19 @@ redo:
 	barrier();
 
 	if (likely(page == c->page)) {
-		set_freepointer(s, object, c->freelist);
+		set_freepointer(s, tail_obj, c->freelist);
 
 		if (unlikely(!this_cpu_cmpxchg_double(
 				s->cpu_slab->freelist, s->cpu_slab->tid,
 				c->freelist, tid,
-				object, next_tid(tid)))) {
+				head, next_tid(tid)))) {
 
 			note_cmpxchg_failure("slab_free", s, tid);
 			goto redo;
 		}
 		stat(s, FREE_FASTPATH);
 	} else
-		__slab_free(s, page, x, addr);
+		__slab_free(s, page, head, tail_obj, cnt, addr);
 
 }
 
@@ -2753,7 +2802,7 @@ void kmem_cache_free(struct kmem_cache *s, void *x)
 	s = cache_from_obj(s, x);
 	if (!s)
 		return;
-	slab_free(s, virt_to_head_page(x), x, _RET_IP_);
+	slab_free(s, virt_to_head_page(x), x, NULL, 1, _RET_IP_);
 	trace_kmem_cache_free(_RET_IP_, x);
 }
 EXPORT_SYMBOL(kmem_cache_free);
@@ -2788,7 +2837,7 @@ void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p)
 			c->tid = next_tid(c->tid);
 			local_irq_enable();
 			/* Slowpath: overhead locked cmpxchg_double_slab */
-			__slab_free(s, page, object, _RET_IP_);
+			__slab_free(s, page, object, object, 1, _RET_IP_);
 			local_irq_disable();
 			c = this_cpu_ptr(s->cpu_slab);
 		}
@@ -3523,7 +3572,7 @@ void kfree(const void *x)
 		__free_kmem_pages(page, compound_order(page));
 		return;
 	}
-	slab_free(page->slab_cache, page, object, _RET_IP_);
+	slab_free(page->slab_cache, page, object, NULL, 1, _RET_IP_);
 }
 EXPORT_SYMBOL(kfree);