From: Wang Hai wanghai38@huawei.com
stable inclusion from linux-4.19.172 commit 08b227d9f380aff229fe7eb3e43c0d90ac14ec38
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commit 757fed1d0898b893d7daa84183947c70f27632f3 upstream.
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 vbabka@suse.cz Signed-off-by: Wang Hai wanghai38@huawei.com Cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com Signed-off-by: Cheng Jian cj.chengjian@huawei.com --- mm/slub.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/mm/slub.c b/mm/slub.c index 3cfec27018ac..45b5353e0938 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -5833,10 +5833,8 @@ 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)