Messages in this thread Patch in this message | | | From | Igor Mammedov <> | Subject | [PATCH] memcg: do not expose uninitialized mem_cgroup_per_node to world | Date | Wed, 1 Jun 2011 12:44:04 +0200 |
| |
Freshly allocated 'mem_cgroup_per_node' list entries must be initialized before the rest of the kernel can see them. Otherwise zero initialized list fields can lead to race condition at mem_cgroup_force_empty_list: pc = list_entry(list->prev, struct page_cgroup, lru); where 'pc' will be something like 0xfffffffc if list->prev is 0 and cause page fault later when 'pc' is dereferenced.
Signed-off-by: Igor Mammedov <imammedo@redhat.com> --- mm/memcontrol.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index bd9052a..ee7cb4c 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -4707,7 +4707,6 @@ static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node) if (!pn) return 1; - mem->info.nodeinfo[node] = pn; for (zone = 0; zone < MAX_NR_ZONES; zone++) { mz = &pn->zoneinfo[zone]; for_each_lru(l) @@ -4716,6 +4715,7 @@ static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node) mz->on_tree = false; mz->mem = mem; } + mem->info.nodeinfo[node] = pn; return 0; } -- 1.7.1
| |