memcgroup: fix spurious EBUSY on memory cgroup removal

Call mm_free_cgroup earlier.  Otherwise a reference due to lazy mm switching
can prevent cgroup removal.

Signed-off-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/kernel/fork.c b/kernel/fork.c
index dd249c37b3a3..9c042f901570 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -394,7 +394,6 @@ void __mmdrop(struct mm_struct *mm)
 {
         BUG_ON(mm == &init_mm);
         mm_free_pgd(mm);
-        mm_free_cgroup(mm);
         destroy_context(mm);
         free_mm(mm);
 }
@@ -416,6 +415,7 @@ void mmput(struct mm_struct *mm)
                         spin_unlock(&mmlist_lock);
                 }
                 put_swap_token(mm);
+                mm_free_cgroup(mm);
                 mmdrop(mm);
         }
 }