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authorKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>2009-01-07 21:08:32 -0500
committerLinus Torvalds <torvalds@linux-foundation.org>2009-01-08 11:31:10 -0500
commita7ba0eef3af51cd1b6fc4028e4705b3ea2ea9469 (patch)
tree70e43097041eed321be38d1af4ed65e41d1ebff9
parent03f3c433648a97ae7c86be789edba67690f6ea60 (diff)
memcg: fix double free and make refcnt sane
1. Fix double-free BUG in error route of mem_cgroup_create(). mem_cgroup_free() itself frees per-zone-info. 2. Making refcnt of memcg simple. Add 1 refcnt at creation and call free when refcnt goes down to 0. Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Paul Menage <menage@google.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/memcontrol.c21
1 files changed, 6 insertions, 15 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 0ed61e27d526..4f9a9c5a02e2 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2092,14 +2092,10 @@ static struct mem_cgroup *mem_cgroup_alloc(void)
2092 * Removal of cgroup itself succeeds regardless of refs from swap. 2092 * Removal of cgroup itself succeeds regardless of refs from swap.
2093 */ 2093 */
2094 2094
2095static void mem_cgroup_free(struct mem_cgroup *mem) 2095static void __mem_cgroup_free(struct mem_cgroup *mem)
2096{ 2096{
2097 int node; 2097 int node;
2098 2098
2099 if (atomic_read(&mem->refcnt) > 0)
2100 return;
2101
2102
2103 for_each_node_state(node, N_POSSIBLE) 2099 for_each_node_state(node, N_POSSIBLE)
2104 free_mem_cgroup_per_zone_info(mem, node); 2100 free_mem_cgroup_per_zone_info(mem, node);
2105 2101
@@ -2116,11 +2112,8 @@ static void mem_cgroup_get(struct mem_cgroup *mem)
2116 2112
2117static void mem_cgroup_put(struct mem_cgroup *mem) 2113static void mem_cgroup_put(struct mem_cgroup *mem)
2118{ 2114{
2119 if (atomic_dec_and_test(&mem->refcnt)) { 2115 if (atomic_dec_and_test(&mem->refcnt))
2120 if (!mem->obsolete) 2116 __mem_cgroup_free(mem);
2121 return;
2122 mem_cgroup_free(mem);
2123 }
2124} 2117}
2125 2118
2126 2119
@@ -2170,12 +2163,10 @@ mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
2170 2163
2171 if (parent) 2164 if (parent)
2172 mem->swappiness = get_swappiness(parent); 2165 mem->swappiness = get_swappiness(parent);
2173 2166 atomic_set(&mem->refcnt, 1);
2174 return &mem->css; 2167 return &mem->css;
2175free_out: 2168free_out:
2176 for_each_node_state(node, N_POSSIBLE) 2169 __mem_cgroup_free(mem);
2177 free_mem_cgroup_per_zone_info(mem, node);
2178 mem_cgroup_free(mem);
2179 return ERR_PTR(-ENOMEM); 2170 return ERR_PTR(-ENOMEM);
2180} 2171}
2181 2172
@@ -2190,7 +2181,7 @@ static void mem_cgroup_pre_destroy(struct cgroup_subsys *ss,
2190static void mem_cgroup_destroy(struct cgroup_subsys *ss, 2181static void mem_cgroup_destroy(struct cgroup_subsys *ss,
2191 struct cgroup *cont) 2182 struct cgroup *cont)
2192{ 2183{
2193 mem_cgroup_free(mem_cgroup_from_cont(cont)); 2184 mem_cgroup_put(mem_cgroup_from_cont(cont));
2194} 2185}
2195 2186
2196static int mem_cgroup_populate(struct cgroup_subsys *ss, 2187static int mem_cgroup_populate(struct cgroup_subsys *ss,