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Commit f0188f47 authored by Ravikiran G Thirumalai's avatar Ravikiran G Thirumalai Committed by Linus Torvalds
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[PATCH] slab: Avoid deadlock at kmem_cache_create/kmem_cache_destroy 



Prevents deadlock situation between
kmem_cache_create()/kmem_cache_destory(), and kmem_cache_create() /cpu
hotplug.  The locking order probably got moved over time.

Signed-off-by: default avatarRavikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: default avatarShai Fultheim <shai@scalex86.org>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 8e36709d

mm/slab.c

+7 −3
Original line number Diff line number Diff line
@@ -1717,6 +1717,12 @@ kmem_cache_create (const char *name, size_t size, size_t align, 
		BUG();

	}



	/*

	 * Prevent CPUs from coming and going.

	 * lock_cpu_hotplug() nests outside cache_chain_mutex

	 */

	lock_cpu_hotplug();



	mutex_lock(&cache_chain_mutex);



	list_for_each(p, &cache_chain) {
@@ -1918,8 +1924,6 @@ kmem_cache_create (const char *name, size_t size, size_t align, 
	cachep->dtor = dtor;

	cachep->name = name;



	/* Don't let CPUs to come and go */

	lock_cpu_hotplug();



	if (g_cpucache_up == FULL) {

		enable_cpucache(cachep);
@@ -1978,12 +1982,12 @@ kmem_cache_create (const char *name, size_t size, size_t align, 


	/* cache setup completed, link it into the list */

	list_add(&cachep->next, &cache_chain);

	unlock_cpu_hotplug();

      oops:

	if (!cachep && (flags & SLAB_PANIC))

		panic("kmem_cache_create(): failed to create slab `%s'\n",

		      name);

	mutex_unlock(&cache_chain_mutex);

	unlock_cpu_hotplug();

	return cachep;

}

EXPORT_SYMBOL(kmem_cache_create);