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| author | KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> | 2009-01-07 18:08:32 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-01-08 08:31:10 -0800 |
| commit | a7ba0eef3af51cd1b6fc4028e4705b3ea2ea9469 (patch) | |
| tree | 70e43097041eed321be38d1af4ed65e41d1ebff9 /mm/memcontrol.c | |
| parent | 03f3c433648a97ae7c86be789edba67690f6ea60 (diff) | |
| download | linux-a7ba0eef3af51cd1b6fc4028e4705b3ea2ea9469.tar.gz linux-a7ba0eef3af51cd1b6fc4028e4705b3ea2ea9469.tar.bz2 linux-a7ba0eef3af51cd1b6fc4028e4705b3ea2ea9469.zip | |
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>
Diffstat (limited to 'mm/memcontrol.c')
| -rw-r--r-- | mm/memcontrol.c | 21 |
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) * Removal of cgroup itself succeeds regardless of refs from swap. */ -static void mem_cgroup_free(struct mem_cgroup *mem) +static void __mem_cgroup_free(struct mem_cgroup *mem) { int node; - if (atomic_read(&mem->refcnt) > 0) - return; - - for_each_node_state(node, N_POSSIBLE) free_mem_cgroup_per_zone_info(mem, node); @@ -2116,11 +2112,8 @@ static void mem_cgroup_get(struct mem_cgroup *mem) static void mem_cgroup_put(struct mem_cgroup *mem) { - if (atomic_dec_and_test(&mem->refcnt)) { - if (!mem->obsolete) - return; - mem_cgroup_free(mem); - } + if (atomic_dec_and_test(&mem->refcnt)) + __mem_cgroup_free(mem); } @@ -2170,12 +2163,10 @@ mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont) if (parent) mem->swappiness = get_swappiness(parent); - + atomic_set(&mem->refcnt, 1); return &mem->css; free_out: - for_each_node_state(node, N_POSSIBLE) - free_mem_cgroup_per_zone_info(mem, node); - mem_cgroup_free(mem); + __mem_cgroup_free(mem); return ERR_PTR(-ENOMEM); } @@ -2190,7 +2181,7 @@ static void mem_cgroup_pre_destroy(struct cgroup_subsys *ss, static void mem_cgroup_destroy(struct cgroup_subsys *ss, struct cgroup *cont) { - mem_cgroup_free(mem_cgroup_from_cont(cont)); + mem_cgroup_put(mem_cgroup_from_cont(cont)); } static int mem_cgroup_populate(struct cgroup_subsys *ss, |