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authorVladimir Davydov <vdavydov@virtuozzo.com>2016-10-08 02:57:29 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2016-10-08 04:46:26 +0300
commit58fa2a5512d9f224775fb01433f195e639953c5f (patch)
tree2462be9a9e44436cb6f4689800e3bb6c735c7877 /mm/memcontrol.c
parent252e5c6e2e5b4557599ef86ea5d02b0395e9056c (diff)
downloadlinux-58fa2a5512d9f224775fb01433f195e639953c5f.tar.xz
mm: memcontrol: add sanity checks for memcg->id.ref on get/put
Link: http://lkml.kernel.org/r/1c5ddb1c171dbdfc3262252769d6138a29b35b70.1470219853.git.vdavydov@virtuozzo.com Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memcontrol.c')
-rw-r--r--mm/memcontrol.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 48747ef5b88f..5579e762b1ce 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4062,11 +4062,13 @@ static DEFINE_IDR(mem_cgroup_idr);
static void mem_cgroup_id_get_many(struct mem_cgroup *memcg, unsigned int n)
{
+ VM_BUG_ON(atomic_read(&memcg->id.ref) <= 0);
atomic_add(n, &memcg->id.ref);
}
static void mem_cgroup_id_put_many(struct mem_cgroup *memcg, unsigned int n)
{
+ VM_BUG_ON(atomic_read(&memcg->id.ref) < n);
if (atomic_sub_and_test(n, &memcg->id.ref)) {
idr_remove(&mem_cgroup_idr, memcg->id.id);
memcg->id.id = 0;
@@ -4255,8 +4257,10 @@ fail:
static int mem_cgroup_css_online(struct cgroup_subsys_state *css)
{
+ struct mem_cgroup *memcg = mem_cgroup_from_css(css);
+
/* Online state pins memcg ID, memcg ID pins CSS */
- mem_cgroup_id_get(mem_cgroup_from_css(css));
+ atomic_set(&memcg->id.ref, 1);
css_get(css);
return 0;
}