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Revert "mm/slub: fix a memory leak in sysfs_slab_add()"
authorWang Hai <wanghai38@huawei.com>
Thu, 28 Jan 2021 11:32:50 +0000 (19:32 +0800)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sat, 30 Jan 2021 12:32:11 +0000 (13:32 +0100)
commit08b227d9f380aff229fe7eb3e43c0d90ac14ec38
tree219c27172b5adc123462cf1ca3d0495e4d6fd2fe
parent4e5ee86dcb0003ae9ed0b477e47a1d0aaf2f8c67
Revert "mm/slub: fix a memory leak in sysfs_slab_add()"

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>
mm/slub.c