bsdacct: account dying tasks in all relevant namespaces

This just makes the acct_proces walk the pid namespaces from current up to
the top and account a task in each with the accounting turned on.

ns->parent access if safe lockless, since current it still alive and holds
its namespace, which in turn holds its parent.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Cc: Balbir Singh <balbir@in.ibm.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, 14 insertions, 7 deletions

diff --git a/kernel/acct.c b/kernel/acct.c
index 7fc9f9dd1e9e..0feba97e114e 100644
--- a/kernel/acct.c
+++ b/kernel/acct.c
@@ -631,15 +631,9 @@ void acct_collect(long exitcode, int group_dead)
         spin_unlock_irq(&current->sighand->siglock);
 }
 
-/**
- * acct_process - now just a wrapper around do_acct_process
- *
- * handles process accounting for an exiting task
- */
-void acct_process(void)
+static void acct_process_in_ns(struct pid_namespace *ns)
 {
         struct file *file = NULL;
-        struct pid_namespace *ns = task_active_pid_ns(current);
         struct bsd_acct_struct *acct;
 
         acct = ns->bacct;
@@ -661,3 +655,16 @@ void acct_process(void)
         do_acct_process(acct, ns, file);
         fput(file);
 }
+
+/**
+ * acct_process - now just a wrapper around do_acct_process
+ *
+ * handles process accounting for an exiting task
+ */
+void acct_process(void)
+{
+        struct pid_namespace *ns;
+
+        for (ns = task_active_pid_ns(current); ns != NULL; ns = ns->parent)
+                acct_process_in_ns(ns);
+}