From 0c18d7a5df82524e634637c3aec24d4cba096442 Mon Sep 17 00:00:00 2001
From: Pavel Emelyanov <xemul@openvz.org>
Date: Fri, 25 Jul 2008 01:48:49 -0700
Subject: [PATCH] bsdacct: fix and add comments around acct_process()
Fix the one describing what this function is and add one more - about
locking absence around pid namespaces loop.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
kernel/acct.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/kernel/acct.c b/kernel/acct.c
index 0feba97e114e4..dd68b90594181 100644
--- a/kernel/acct.c
+++ b/kernel/acct.c
@@ -657,7 +657,8 @@ static void acct_process_in_ns(struct pid_namespace *ns)
}
/**
- * acct_process - now just a wrapper around do_acct_process
+ * acct_process - now just a wrapper around acct_process_in_ns,
+ * which in turn is a wrapper around do_acct_process.
*
* handles process accounting for an exiting task
*/
@@ -665,6 +666,11 @@ void acct_process(void)
{
struct pid_namespace *ns;
+ /*
+ * This loop is safe lockless, since current is still
+ * alive and holds its namespace, which in turn holds
+ * its parent.
+ */
for (ns = task_active_pid_ns(current); ns != NULL; ns = ns->parent)
acct_process_in_ns(ns);
}
--
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