Handle pid namespaces in cgroups code

There's one place that works with task pids - its the "tasks" file in cgroups.
 The read/write handlers assume, that the pid values go to/come from the user
space and thus it is a virtual pid, i.e.  the pid as it is seen from inside a
namespace.

Tune the code accordingly.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: 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, 2 insertions, 2 deletions

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 2c5cccbe12e2..4766bb65e4d9 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1269,7 +1269,7 @@ static int attach_task_by_pid(struct cgroup *cgrp, char *pidbuf)
 
         if (pid) {
                 rcu_read_lock();
-                tsk = find_task_by_pid(pid);
+                tsk = find_task_by_vpid(pid);
                 if (!tsk || tsk->flags & PF_EXITING) {
                         rcu_read_unlock();
                         return -ESRCH;
@@ -1955,7 +1955,7 @@ static int pid_array_load(pid_t *pidarray, int npids, struct cgroup *cgrp)
         while ((tsk = cgroup_iter_next(cgrp, &it))) {
                 if (unlikely(n == npids))
                         break;
-                pidarray[n++] = task_pid_nr(tsk);
+                pidarray[n++] = task_pid_vnr(tsk);
         }
         cgroup_iter_end(cgrp, &it);
         return n;