diff options
| author | Vladimir Davydov <vdavydov@virtuozzo.com> | 2016-10-07 16:57:29 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-10-07 18:46:26 -0700 |
| commit | 58fa2a5512d9f224775fb01433f195e639953c5f (patch) | |
| tree | 2462be9a9e44436cb6f4689800e3bb6c735c7877 /mm/memcontrol.c | |
| parent | 252e5c6e2e5b4557599ef86ea5d02b0395e9056c (diff) | |
| download | lwn-58fa2a5512d9f224775fb01433f195e639953c5f.tar.gz lwn-58fa2a5512d9f224775fb01433f195e639953c5f.zip | |
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.c | 6 |
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; } |