From 08423e3fa52d9432e4ef82c88d6b943f49c2696f Mon Sep 17 00:00:00 2001 From: CAI Qian Date: Thu, 24 Jan 2013 22:50:09 -0500 Subject: [PATCH] slub: assign refcount for kmalloc_caches This is for stable-3.7.y only and this problem has already been solved in mainline through some slab/slub re-work which isn't suitable to backport here. See create_kmalloc_cache() in mm/slab_common.c there. commit cce89f4f6911286500cf7be0363f46c9b0a12ce0('Move kmem_cache refcounting to common code') moves some refcount manipulation code to common code. Unfortunately, it also removed refcount assignment for kmalloc_caches. So, kmalloc_caches's refcount is initially 0. This makes erroneous situation. Paul Hargrove report that when he create a 8-byte kmem_cache and destory it, he encounter below message. 'Objects remaining in kmalloc-8 on kmem_cache_close()' 8-byte kmem_cache merge with 8-byte kmalloc cache and refcount is increased by one. So, resulting refcount is 1. When destroy it, it hit refcount = 0, then kmem_cache_close() is executed and error message is printed. This patch assign initial refcount 1 to kmalloc_caches, so fix this erroneous situation. Reported-by: Paul Hargrove Cc: Christoph Lameter Signed-off-by: Joonsoo Kim Signed-off-by: CAI Qian Signed-off-by: Greg Kroah-Hartman --- mm/slub.c | 1 + 1 file changed, 1 insertion(+) diff --git a/mm/slub.c b/mm/slub.c index a0d698467f706..321afab6a38d8 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -3279,6 +3279,7 @@ static struct kmem_cache *__init create_kmalloc_cache(const char *name, if (kmem_cache_open(s, flags)) goto panic; + s->refcount = 1; list_add(&s->list, &slab_caches); return s; -- 2.47.2