[patch] memcg: null dereference on allocation failure

From: Dan Carpenter
Date: Thu Oct 28 2010 - 07:12:58 EST


The original code had a null dereference if alloc_percpu() failed.
This was introduced in 711d3d2c9bc3 "memcg: cpu hotplug aware percpu
count updates"

Signed-off-by: Dan Carpenter <error27@xxxxxxxxx>

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 9a99cfa..2efa8ea 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4208,15 +4208,17 @@ static struct mem_cgroup *mem_cgroup_alloc(void)

memset(mem, 0, size);
mem->stat = alloc_percpu(struct mem_cgroup_stat_cpu);
- if (!mem->stat) {
- if (size < PAGE_SIZE)
- kfree(mem);
- else
- vfree(mem);
- mem = NULL;
- }
+ if (!mem->stat)
+ goto out_free;
spin_lock_init(&mem->pcp_counter_lock);
return mem;
+
+out_free:
+ if (size < PAGE_SIZE)
+ kfree(mem);
+ else
+ vfree(mem);
+ return NULL;
}

/*
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/