Commit f1aaee53 authored by Arjan van de Ven's avatar Arjan van de Ven Committed by Linus Torvalds
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[PATCH] lockdep: annotate mm/slab.c

mm/slab.c uses nested locking when dealing with 'off-slab'
caches, in that case it allocates the slab header from the
(on-slab) kmalloc caches. Teach the lock validator about
this by putting all on-slab caches into a separate class.

this patch has no effect on non-lockdep kernels.

Signed-off-by: default avatarArjan van de Ven <>
Signed-off-by: default avatarIngo Molnar <>
Signed-off-by: default avatarLinus Torvalds <>
parent 873623df
......@@ -674,6 +674,37 @@ static struct kmem_cache cache_cache = {
* Slab sometimes uses the kmalloc slabs to store the slab headers
* for other slabs "off slab".
* The locking for this is tricky in that it nests within the locks
* of all other slabs in a few places; to deal with this special
* locking we put on-slab caches into a separate lock-class.
static struct lock_class_key on_slab_key;
static inline void init_lock_keys(struct cache_sizes *s)
int q;
for (q = 0; q < MAX_NUMNODES; q++) {
if (!s->cs_cachep->nodelists[q] || OFF_SLAB(s->cs_cachep))
static inline void init_lock_keys(struct cache_sizes *s)
/* Guard access to the cache-chain. */
static DEFINE_MUTEX(cache_chain_mutex);
static struct list_head cache_chain;
......@@ -1391,6 +1422,7 @@ void __init kmem_cache_init(void)
sizes->cs_dmacachep = kmem_cache_create(names->name_dma,
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