The patch titled
Subject: mm: memcontrol: add sanity checks for memcg->id.ref on get/put
has been added to the -mm tree. Its filename is
mm-memcontrol-add-sanity-checks-for-memcg-idref-on-get-put.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-memcontrol-add-sanity-checks-for-memcg-idref-on-get-put.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-memcontrol-add-sanity-checks-for-memcg-idref-on-get-put.patch
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------------------------------------------------------
From: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx>
Subject: mm: memcontrol: add sanity checks for memcg->id.ref on get/put
Link: http://lkml.kernel.org/r/ad702144f24374cbfb3a35b71658a0ae24ba7d84.1470057819.git.vdavydov@xxxxxxxxxxxxx
Signed-off-by: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff -puN mm/memcontrol.c~mm-memcontrol-add-sanity-checks-for-memcg-idref-on-get-put mm/memcontrol.c
--- a/mm/memcontrol.c~mm-memcontrol-add-sanity-checks-for-memcg-idref-on-get-put
+++ a/mm/memcontrol.c
@@ -4071,18 +4071,22 @@ 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 struct mem_cgroup *mem_cgroup_id_get_active(struct mem_cgroup *memcg)
{
- while (!atomic_inc_not_zero(&memcg->id.ref))
+ while (!atomic_inc_not_zero(&memcg->id.ref)) {
+ VM_BUG_ON(mem_cgroup_is_root(memcg));
memcg = parent_mem_cgroup(memcg);
+ }
return memcg;
}
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;
@@ -4203,6 +4207,7 @@ static struct mem_cgroup *mem_cgroup_all
INIT_LIST_HEAD(&memcg->cgwb_list);
#endif
idr_replace(&mem_cgroup_idr, memcg, memcg->id.id);
+ atomic_set(&memcg->id.ref, 1);
return memcg;
fail:
if (memcg->id.id > 0)
@@ -4272,7 +4277,6 @@ fail:
static int mem_cgroup_css_online(struct cgroup_subsys_state *css)
{
/* Online state pins memcg ID, memcg ID pins CSS */
- mem_cgroup_id_get(mem_cgroup_from_css(css));
css_get(css);
return 0;
}
_
Patches currently in -mm which might be from vdavydov@xxxxxxxxxxxxx are
mm-memcontrol-fix-swap-counter-leak-on-swapout-from-offline-cgroup.patch
mm-memcontrol-fix-memcg-id-ref-counter-on-swap-charge-move.patch
mm-memcontrol-add-sanity-checks-for-memcg-idref-on-get-put.patch
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