From 4ba902b5741859a04fdb90d675b9a87721a3fd59 Mon Sep 17 00:00:00 2001 From: Glauber Costa Date: Tue, 12 Feb 2013 13:46:22 -0800 Subject: memcg: fix kmemcg registration for late caches The designed workflow for the caches in kmemcg is: register it with memcg_register_cache() if kmemcg is already available or later on when a new kmemcg appears at memcg_update_cache_sizes() which will handle all caches in the system. The caches created at boot time will be handled by the later, and the memcg-caches as well as any system caches that are registered later on by the former. There is a bug, however, in memcg_register_cache: we correctly set up the array size, but do not mark the cache as a root cache. This means that allocations for any cache appearing late in the game will see memcg->memcg_params->is_root_cache == false, and in particular, trigger VM_BUG_ON(!cachep->memcg_params->is_root_cache) in __memcg_kmem_cache_get. The obvious fix is to include the missing assignment. Signed-off-by: Glauber Costa Cc: Michal Hocko Cc: Johannes Weiner Cc: KAMEZAWA Hiroyuki Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memcontrol.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 09255ec8159..fbb60b103e6 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3030,7 +3030,9 @@ int memcg_register_cache(struct mem_cgroup *memcg, struct kmem_cache *s, if (memcg) { s->memcg_params->memcg = memcg; s->memcg_params->root_cache = root_cache; - } + } else + s->memcg_params->is_root_cache = true; + return 0; } -- cgit v1.2.3-70-g09d2