From: Wang Hai Date: Thu, 28 Jan 2021 11:32:50 +0000 (+0800) Subject: Revert "mm/slub: fix a memory leak in sysfs_slab_add()" X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=757fed1d0898b893d7daa84183947c70f27632f3;p=linux.git Revert "mm/slub: fix a memory leak in sysfs_slab_add()" This reverts commit dde3c6b72a16c2db826f54b2d49bdea26c3534a2. syzbot report a double-free bug. The following case can cause this bug. - mm/slab_common.c: create_cache(): if the __kmem_cache_create() fails, it does: out_free_cache: kmem_cache_free(kmem_cache, s); - but __kmem_cache_create() - at least for slub() - will have done sysfs_slab_add(s) -> sysfs_create_group() .. fails .. -> kobject_del(&s->kobj); .. which frees s ... We can't remove the kmem_cache_free() in create_cache(), because other error cases of __kmem_cache_create() do not free this. So, revert the commit dde3c6b72a16 ("mm/slub: fix a memory leak in sysfs_slab_add()") to fix this. Reported-by: syzbot+d0bd96b4696c1ef67991@syzkaller.appspotmail.com Fixes: dde3c6b72a16 ("mm/slub: fix a memory leak in sysfs_slab_add()") Acked-by: Vlastimil Babka Signed-off-by: Wang Hai Cc: Signed-off-by: Linus Torvalds --- diff --git a/mm/slub.c b/mm/slub.c index 69742ab9a21d3..7ecbbbe5bc0c1 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -5625,10 +5625,8 @@ static int sysfs_slab_add(struct kmem_cache *s) s->kobj.kset = kset; err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, "%s", name); - if (err) { - kobject_put(&s->kobj); + if (err) goto out; - } err = sysfs_create_group(&s->kobj, &slab_attr_group); if (err)