slub: validation of slabs (metadata and guard zones)

[safe/jmp/linux-2.6] / mm / slub.c

diff --git a/mm/slub.c b/mm/slub.c
index c4f40d3..69ee7f8 100644 (file)
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -670,8 +670,6 @@ static void add_full(struct kmem_cache *s, struct page *page)
 
        VM_BUG_ON(!irqs_disabled());
 
-       VM_BUG_ON(!irqs_disabled());
-
        if (!(s->flags & SLAB_STORE_USER))
                return;
 
@@ -2551,6 +2549,99 @@ void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags,
 
 #ifdef CONFIG_SYSFS
 
+static int validate_slab(struct kmem_cache *s, struct page *page)
+{
+       void *p;
+       void *addr = page_address(page);
+       unsigned long map[BITS_TO_LONGS(s->objects)];
+
+       if (!check_slab(s, page) ||
+                       !on_freelist(s, page, NULL))
+               return 0;
+
+       /* Now we know that a valid freelist exists */
+       bitmap_zero(map, s->objects);
+
+       for(p = page->freelist; p; p = get_freepointer(s, p)) {
+               set_bit((p - addr) / s->size, map);
+               if (!check_object(s, page, p, 0))
+                       return 0;
+       }
+
+       for(p = addr; p < addr + s->objects * s->size; p += s->size)
+               if (!test_bit((p - addr) / s->size, map))
+                       if (!check_object(s, page, p, 1))
+                               return 0;
+       return 1;
+}
+
+static void validate_slab_slab(struct kmem_cache *s, struct page *page)
+{
+       if (slab_trylock(page)) {
+               validate_slab(s, page);
+               slab_unlock(page);
+       } else
+               printk(KERN_INFO "SLUB %s: Skipped busy slab 0x%p\n",
+                       s->name, page);
+
+       if (s->flags & DEBUG_DEFAULT_FLAGS) {
+               if (!PageError(page))
+                       printk(KERN_ERR "SLUB %s: PageError not set "
+                               "on slab 0x%p\n", s->name, page);
+       } else {
+               if (PageError(page))
+                       printk(KERN_ERR "SLUB %s: PageError set on "
+                               "slab 0x%p\n", s->name, page);
+       }
+}
+
+static int validate_slab_node(struct kmem_cache *s, struct kmem_cache_node *n)
+{
+       unsigned long count = 0;
+       struct page *page;
+       unsigned long flags;
+
+       spin_lock_irqsave(&n->list_lock, flags);
+
+       list_for_each_entry(page, &n->partial, lru) {
+               validate_slab_slab(s, page);
+               count++;
+       }
+       if (count != n->nr_partial)
+               printk(KERN_ERR "SLUB %s: %ld partial slabs counted but "
+                       "counter=%ld\n", s->name, count, n->nr_partial);
+
+       if (!(s->flags & SLAB_STORE_USER))
+               goto out;
+
+       list_for_each_entry(page, &n->full, lru) {
+               validate_slab_slab(s, page);
+               count++;
+       }
+       if (count != atomic_long_read(&n->nr_slabs))
+               printk(KERN_ERR "SLUB: %s %ld slabs counted but "
+                       "counter=%ld\n", s->name, count,
+                       atomic_long_read(&n->nr_slabs));
+
+out:
+       spin_unlock_irqrestore(&n->list_lock, flags);
+       return count;
+}
+
+static unsigned long validate_slab_cache(struct kmem_cache *s)
+{
+       int node;
+       unsigned long count = 0;
+
+       flush_all(s);
+       for_each_online_node(node) {
+               struct kmem_cache_node *n = get_node(s, node);
+
+               count += validate_slab_node(s, n);
+       }
+       return count;
+}
+
 static unsigned long count_partial(struct kmem_cache_node *n)
 {
        unsigned long flags;
@@ -2680,7 +2771,6 @@ struct slab_attribute {
        static struct slab_attribute _name##_attr =  \
        __ATTR(_name, 0644, _name##_show, _name##_store)
 
-
 static ssize_t slab_size_show(struct kmem_cache *s, char *buf)
 {
        return sprintf(buf, "%d\n", s->size);
@@ -2886,6 +2976,22 @@ static ssize_t store_user_store(struct kmem_cache *s,
 }
 SLAB_ATTR(store_user);
 
+static ssize_t validate_show(struct kmem_cache *s, char *buf)
+{
+       return 0;
+}
+
+static ssize_t validate_store(struct kmem_cache *s,
+                       const char *buf, size_t length)
+{
+       if (buf[0] == '1')
+               validate_slab_cache(s);
+       else
+               return -EINVAL;
+       return length;
+}
+SLAB_ATTR(validate);
+
 #ifdef CONFIG_NUMA
 static ssize_t defrag_ratio_show(struct kmem_cache *s, char *buf)
 {
@@ -2925,6 +3031,7 @@ static struct attribute * slab_attrs[] = {
        &red_zone_attr.attr,
        &poison_attr.attr,
        &store_user_attr.attr,
+       &validate_attr.attr,
 #ifdef CONFIG_ZONE_DMA
        &cache_dma_attr.attr,
 #endif