From f0188f47482efdbd2e005103bb4f0224a835dfad Mon Sep 17 00:00:00 2001 From: Ravikiran G Thirumalai Date: Fri, 10 Feb 2006 01:51:13 -0800 Subject: [PATCH] [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: Ravikiran Thirumalai Signed-off-by: Shai Fultheim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/slab.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/mm/slab.c b/mm/slab.c index d66c2b0d97..add05d808a 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -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); -- 2.39.5