[PATCH] memcg: fix oops in mem_cgroup_shrink_usage

Hugh Dickins
2008-08-06T14:16:50Z

Got an oops in mem_cgroup_shrink_usage() when testing loop over tmpfs:
yes, of course, loop0 has no mm: other entry points check but this didn't.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
---

mm/memcontrol.c | 2 ++
1 file changed, 2 insertions(+)

--- 2.6.27-rc2/mm/memcontrol.c 2008-08-06 08:36:20.000000000 +0100
+++ linux/mm/memcontrol.c 2008-08-06 09:05:26.000000000 +0100
@@ -796,6 +796,8 @@ int mem_cgroup_shrink_usage(struct mm_st

if (mem_cgroup_subsys.disabled)
return 0;
+ if (!mm)
+ return 0;

rcu_read_lock();
mem = mem_cgroup_from_task(rcu_dereference(mm->owner));