[PATCH] lockdep: annotate SLAB code
Teach special (recursive) locking code to the lock validator. Has no effect on non-lockdep kernels. Fix initialize-locks-via-memcpy assumptions. Effects on non-lockdep kernels: the subclass nesting parameter is passed into cache_free_alien() and __cache_free(), and turns one internal kmem_cache_free() call into an open-coded __cache_free() call. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Christoph Lameter <clameter@engr.sgi.com> Cc: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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parent
897c6ff956
commit
2b2d5493e1
59
mm/slab.c
59
mm/slab.c
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@ -1021,7 +1021,8 @@ static void drain_alien_cache(struct kmem_cache *cachep,
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}
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}
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static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
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static inline int cache_free_alien(struct kmem_cache *cachep, void *objp,
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int nesting)
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{
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struct slab *slabp = virt_to_slab(objp);
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int nodeid = slabp->nodeid;
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@ -1039,7 +1040,7 @@ static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
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STATS_INC_NODEFREES(cachep);
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if (l3->alien && l3->alien[nodeid]) {
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alien = l3->alien[nodeid];
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spin_lock(&alien->lock);
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spin_lock_nested(&alien->lock, nesting);
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if (unlikely(alien->avail == alien->limit)) {
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STATS_INC_ACOVERFLOW(cachep);
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__drain_alien_cache(cachep, alien, nodeid);
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@ -1068,7 +1069,8 @@ static inline void free_alien_cache(struct array_cache **ac_ptr)
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{
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}
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static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
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static inline int cache_free_alien(struct kmem_cache *cachep, void *objp,
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int nesting)
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{
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return 0;
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}
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@ -1272,6 +1274,11 @@ static void init_list(struct kmem_cache *cachep, struct kmem_list3 *list,
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local_irq_disable();
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memcpy(ptr, list, sizeof(struct kmem_list3));
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/*
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* Do not assume that spinlocks can be initialized via memcpy:
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*/
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spin_lock_init(&ptr->list_lock);
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MAKE_ALL_LISTS(cachep, ptr, nodeid);
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cachep->nodelists[nodeid] = ptr;
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local_irq_enable();
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@ -1398,7 +1405,7 @@ void __init kmem_cache_init(void)
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}
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/* 4) Replace the bootstrap head arrays */
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{
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void *ptr;
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struct array_cache *ptr;
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ptr = kmalloc(sizeof(struct arraycache_init), GFP_KERNEL);
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@ -1406,6 +1413,11 @@ void __init kmem_cache_init(void)
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BUG_ON(cpu_cache_get(&cache_cache) != &initarray_cache.cache);
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memcpy(ptr, cpu_cache_get(&cache_cache),
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sizeof(struct arraycache_init));
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/*
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* Do not assume that spinlocks can be initialized via memcpy:
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*/
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spin_lock_init(&ptr->lock);
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cache_cache.array[smp_processor_id()] = ptr;
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local_irq_enable();
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@ -1416,6 +1428,11 @@ void __init kmem_cache_init(void)
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!= &initarray_generic.cache);
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memcpy(ptr, cpu_cache_get(malloc_sizes[INDEX_AC].cs_cachep),
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sizeof(struct arraycache_init));
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/*
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* Do not assume that spinlocks can be initialized via memcpy:
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*/
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spin_lock_init(&ptr->lock);
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malloc_sizes[INDEX_AC].cs_cachep->array[smp_processor_id()] =
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ptr;
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local_irq_enable();
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@ -1743,6 +1760,8 @@ static void slab_destroy_objs(struct kmem_cache *cachep, struct slab *slabp)
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}
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#endif
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static void __cache_free(struct kmem_cache *cachep, void *objp, int nesting);
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/**
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* slab_destroy - destroy and release all objects in a slab
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* @cachep: cache pointer being destroyed
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@ -1766,8 +1785,17 @@ static void slab_destroy(struct kmem_cache *cachep, struct slab *slabp)
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call_rcu(&slab_rcu->head, kmem_rcu_free);
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} else {
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kmem_freepages(cachep, addr);
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if (OFF_SLAB(cachep))
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kmem_cache_free(cachep->slabp_cache, slabp);
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if (OFF_SLAB(cachep)) {
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unsigned long flags;
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/*
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* lockdep: we may nest inside an already held
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* ac->lock, so pass in a nesting flag:
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*/
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local_irq_save(flags);
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__cache_free(cachep->slabp_cache, slabp, 1);
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local_irq_restore(flags);
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}
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}
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}
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@ -3072,7 +3100,16 @@ static void free_block(struct kmem_cache *cachep, void **objpp, int nr_objects,
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if (slabp->inuse == 0) {
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if (l3->free_objects > l3->free_limit) {
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l3->free_objects -= cachep->num;
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/*
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* It is safe to drop the lock. The slab is
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* no longer linked to the cache. cachep
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* cannot disappear - we are using it and
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* all destruction of caches must be
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* serialized properly by the user.
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*/
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spin_unlock(&l3->list_lock);
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slab_destroy(cachep, slabp);
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spin_lock(&l3->list_lock);
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} else {
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list_add(&slabp->list, &l3->slabs_free);
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}
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@ -3098,7 +3135,7 @@ static void cache_flusharray(struct kmem_cache *cachep, struct array_cache *ac)
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#endif
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check_irq_off();
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l3 = cachep->nodelists[node];
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spin_lock(&l3->list_lock);
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spin_lock_nested(&l3->list_lock, SINGLE_DEPTH_NESTING);
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if (l3->shared) {
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struct array_cache *shared_array = l3->shared;
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int max = shared_array->limit - shared_array->avail;
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@ -3141,14 +3178,14 @@ free_done:
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* Release an obj back to its cache. If the obj has a constructed state, it must
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* be in this state _before_ it is released. Called with disabled ints.
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*/
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static inline void __cache_free(struct kmem_cache *cachep, void *objp)
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static void __cache_free(struct kmem_cache *cachep, void *objp, int nesting)
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{
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struct array_cache *ac = cpu_cache_get(cachep);
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check_irq_off();
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objp = cache_free_debugcheck(cachep, objp, __builtin_return_address(0));
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if (cache_free_alien(cachep, objp))
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if (cache_free_alien(cachep, objp, nesting))
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return;
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if (likely(ac->avail < ac->limit)) {
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@ -3387,7 +3424,7 @@ void kmem_cache_free(struct kmem_cache *cachep, void *objp)
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BUG_ON(virt_to_cache(objp) != cachep);
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local_irq_save(flags);
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__cache_free(cachep, objp);
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__cache_free(cachep, objp, 0);
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local_irq_restore(flags);
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}
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EXPORT_SYMBOL(kmem_cache_free);
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@ -3412,7 +3449,7 @@ void kfree(const void *objp)
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kfree_debugcheck(objp);
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c = virt_to_cache(objp);
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debug_check_no_locks_freed(objp, obj_size(c));
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__cache_free(c, (void *)objp);
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__cache_free(c, (void *)objp, 0);
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local_irq_restore(flags);
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}
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EXPORT_SYMBOL(kfree);
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