On Wed, 20 Jul 2011, Peter Zijlstra wrote:
We just need to annotate the SLAB_DEBUG_OBJECTS slab with a different
key. Something like the below, except that doesn't quite cover cpu
hotplug yet I think.. /me pokes more
Completely untested, hasn't even seen a compiler etc..
Ping? Did someone send me a patch I can apply?
---
mm/slab.c | 65 ++++++++++++++++++++++++++++++++++++++++++++----------------
1 files changed, 47 insertions(+), 18 deletions(-)
diff --git a/mm/slab.c b/mm/slab.c
index d96e223..c13f7e9 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -620,6 +620,37 @@ int slab_is_available(void)
static struct lock_class_key on_slab_l3_key;
static struct lock_class_key on_slab_alc_key;
+static struct lock_class_key debugobj_l3_key;
+static struct lock_class_key debugobj_alc_key;
+
+static void slab_set_lock_classes(struct kmem_cache *cachep,
+ struct lock_class_key *l3_key, struct lock_class_key *alc_key)
+{
+ struct array_cache **alc;
+ struct kmem_list3 *l3;
+ int r;
+
+ l3 = cachep->nodelists[q];
+ if (!l3)
+ return;
+
+ lockdep_set_class(&l3->list_lock, l3_key);
+ alc = l3->alien;
+ /*
+ * FIXME: This check for BAD_ALIEN_MAGIC
+ * should go away when common slab code is taught to
+ * work even without alien caches.
+ * Currently, non NUMA code returns BAD_ALIEN_MAGIC
+ * for alloc_alien_cache,
+ */
+ if (!alc || (unsigned long)alc == BAD_ALIEN_MAGIC)
+ return;
+ for_each_node(r) {
+ if (alc[r])
+ lockdep_set_class(&alc[r]->lock, alc_key);
+ }
+}
+
static void init_node_lock_keys(int q)
{
struct cache_sizes *s = malloc_sizes;
@@ -628,29 +659,14 @@ static void init_node_lock_keys(int q)
return;
for (s = malloc_sizes; s->cs_size != ULONG_MAX; s++) {
- struct array_cache **alc;
struct kmem_list3 *l3;
- int r;
l3 = s->cs_cachep->nodelists[q];
if (!l3 || OFF_SLAB(s->cs_cachep))
continue;
- lockdep_set_class(&l3->list_lock, &on_slab_l3_key);
- alc = l3->alien;
- /*
- * FIXME: This check for BAD_ALIEN_MAGIC
- * should go away when common slab code is taught to
- * work even without alien caches.
- * Currently, non NUMA code returns BAD_ALIEN_MAGIC
- * for alloc_alien_cache,
- */
- if (!alc || (unsigned long)alc == BAD_ALIEN_MAGIC)
- continue;
- for_each_node(r) {
- if (alc[r])
- lockdep_set_class(&alc[r]->lock,
- &on_slab_alc_key);
- }
+
+ slab_set_lock_classes(s->cs_cachep,
+ &on_slab_l3_key, &on_slab_alc_key)
}
}
@@ -2424,6 +2440,19 @@ kmem_cache_create (const char *name, size_t size, size_t align,
goto oops;
}
+ if (flags & SLAB_DEBUG_OBJECTS) {
+ /*
+ * Would deadlock through slab_destroy()->call_rcu()->
+ * debug_object_activate()->kmem_cache_alloc().
+ */
+ WARN_ON_ONCE(flags & SLAB_DESTROY_BY_RCU);
+
+#ifdef CONFIG_LOCKDEP
+ slab_set_lock_classes(cachep,
+ &debugobj_l3_key, &debugobj_alc_key);
+#endif
+ }
+
/* cache setup completed, link it into the list */
list_add(&cachep->next, &cache_chain);
oops:
--
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