• David Rientjes's avatar
    slub: avoid leaking caches or refcounts on sysfs error · 7b8f3b66
    David Rientjes authored
    If a slab cache is mergeable and the sysfs alias cannot be added, the
    target cache shall have its refcount decremented.  kmem_cache_create()
    will return NULL, so if kmem_cache_destroy() is ever called on the target
    cache, it will never be freed if the refcount has been leaked.
    
    Likewise, if a slab cache is not mergeable and the sysfs link cannot be
    added, the new cache shall be removed from the slab_caches list.
    kmem_cache_create() will return NULL, so it will be impossible to call
    kmem_cache_destroy() on it.
    
    Both of these operations require slub_lock since refcount of all slab
    caches and slab_caches are protected by the lock.
    
    In the mergeable case, it would be better to restore objsize and offset
    back to their original values, but this could race with another merge
    since slub_lock was dropped.
    
    Cc: Christoph Lameter <cl@linux-foundation.org>
    Signed-off-by: default avatarDavid Rientjes <rientjes@google.com>
    Signed-off-by: default avatarPekka Enberg <penberg@cs.helsinki.fi>
    7b8f3b66
slub.c 106 KB