pid namespaces: make proc_flush_task() actually from entries from multiple namespaces

This means that proc_flush_task_mnt() is to be called for many proc mounts and
with different ids, depending on the namespace this pid is to be flushed from.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Paul Menage <menage@google.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 16 insertions, 2 deletions

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 50e149e08d96..5e0c6a1ce8b3 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2259,8 +2259,22 @@ out:
 
 void proc_flush_task(struct task_struct *task)
 {
-        proc_flush_task_mnt(proc_mnt, task->pid,
-                        thread_group_leader(task) ? 0 : task->tgid);
+        int i, leader;
+        struct pid *pid, *tgid;
+        struct upid *upid;
+
+        leader = thread_group_leader(task);
+        proc_flush_task_mnt(proc_mnt, task->pid, leader ? task->tgid : 0);
+        pid = task_pid(task);
+        if (pid->level == 0)
+                return;
+
+        tgid = task_tgid(task);
+        for (i = 1; i <= pid->level; i++) {
+                upid = &pid->numbers[i];
+                proc_flush_task_mnt(upid->ns->proc_mnt, upid->nr,
+                                leader ? 0 : tgid->numbers[i].nr);
+        }
 }
 
 static struct dentry *proc_pid_instantiate(struct inode *dir,