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Date: Wed, 4 Apr 2007 21:29:07 -0700 (PDT)
From: Christoph Lameter <clameter@....com>
To: Badari Pulavarty <pbadari@...il.com>
cc: Andrew Morton <akpm@...ux-foundation.org>,
lkml <linux-kernel@...r.kernel.org>
Subject: Re: 2.6.21-rc5-mm4 (SLUB)
Here is a patch that adds validation (only for cpuslabs and partial
slabs but thats where the action is). Apply this patch
and then do
echo 1 >/sys/slab/<cache-to-check>/validate
I suggest to boot with full debugging and then run this on the ACPI slabs.
Signed-off-by: Christoph Lameter <clameter@....com>
Index: linux-2.6.21-rc5-mm4/mm/slub.c
===================================================================
--- linux-2.6.21-rc5-mm4.orig/mm/slub.c 2007-04-04 20:26:03.000000000 -0700
+++ linux-2.6.21-rc5-mm4/mm/slub.c 2007-04-04 21:26:15.000000000 -0700
@@ -2280,6 +2280,67 @@ void *__kmalloc_node_track_caller(size_t
#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 int validate_slab_node(struct kmem_cache *s, struct kmem_cache_node *n)
+{
+ int count = 0;
+ struct page *page;
+ unsigned long flags;
+
+ spin_lock_irqsave(&n->list_lock, flags);
+ list_for_each_entry(page, &n->partial, lru) {
+ if (slab_trylock(page)) {
+ validate_slab(s, page);
+ slab_unlock(page);
+ } else
+ printk(KERN_INFO "Skipped busy slab %p\n", page);
+ count++;
+ }
+ spin_unlock_irqrestore(&n->list_lock, flags);
+ return count;
+}
+
+static void validate_slab_cache(struct kmem_cache *s)
+{
+ int node;
+ int count = 0;
+
+ printk(KERN_INFO "--- Validating slabcache '%s'\n", s->name);
+ flush_all(s);
+ for_each_online_node(node) {
+ struct kmem_cache_node *n = get_node(s, node);
+
+ count += validate_slab_node(s, n);
+ }
+ printk(KERN_INFO "--- Checked %d slabs in '%s'\n",
+ count, s->name);
+}
+
static unsigned long count_partial(struct kmem_cache_node *n)
{
unsigned long flags;
@@ -2402,7 +2463,6 @@ 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);
@@ -2609,6 +2669,22 @@ static ssize_t store_user_store(struct k
}
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)
{
@@ -2648,6 +2724,7 @@ 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
-
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