shinys000114/linux
1
0
Fork 0
mirror of https://github.com/hardkernel/linux.git synced 2026-06-06 10:58:48 +09:00
Code Issues Packages Projects Releases Wiki Activity

mm: kfence: fix missing objcg housekeeping for SLAB

Browse Source 
commit ae085d7f93 upstream.

The objcg is not cleared and put for kfence object when it is freed,
which could lead to memory leak for struct obj_cgroup and wrong
statistics of NR_SLAB_RECLAIMABLE_B or NR_SLAB_UNRECLAIMABLE_B.

Since the last freed object's objcg is not cleared,
mem_cgroup_from_obj() could return the wrong memcg when this kfence
object, which is not charged to any objcgs, is reallocated to other
users.

A real word issue [1] is caused by this bug.

Link: https://lore.kernel.org/all/000000000000cabcb505dae9e577@google.com/ [1]
Reported-by: syzbot+f8c45ccc7d5d45fc5965@syzkaller.appspotmail.com
Fixes: d3fb45f370 ("mm, kfence: insert KFENCE hooks for SLAB")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Muchun Song
2022-03-27 13:18:52 +08:00
committed by Greg Kroah-Hartman
parent 3d7df3f83f
commit dd84d71bcb
1 changed files with 1 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

1
mm/slab.c
View File

@@ -3429,6 +3429,7 @@ static __always_inline void __cache_free(struct kmem_cache *cachep, void *objp,
if (is_kfence_address(objp)) {
kmemleak_free_recursive(objp, cachep->flags);
memcg_slab_free_hook(cachep, &objp, 1);
__kfence_free(objp);
return;
}