Merge commit '517ffce4e1a03aea979fe3a18a3dd1761a24fafb' into arch-sparc

Backmerge from the point in mainline where a trivial conflict had been
introduced (arch/sparc/kernel/sys_sparc_64.c had grown sys_kern_features()
right after where kernel_execve() used to be)

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 25 insertions, 8 deletions

diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
index 478bad2745e3..7b07cc0dfb75 100644
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c
@@ -71,12 +71,22 @@ err_alloc:
 	return NULL;
 }
 
+/* MAX_PID_NS_LEVEL is needed for limiting size of 'struct pid' */
+#define MAX_PID_NS_LEVEL 32
+
 static struct pid_namespace *create_pid_namespace(struct pid_namespace *parent_pid_ns)
 {
 	struct pid_namespace *ns;
 	unsigned int level = parent_pid_ns->level + 1;
-	int i, err = -ENOMEM;
+	int i;
+	int err;
+
+	if (level > MAX_PID_NS_LEVEL) {
+		err = -EINVAL;
+		goto out;
+	}
 
+	err = -ENOMEM;
 	ns = kmem_cache_zalloc(pid_ns_cachep, GFP_KERNEL);
 	if (ns == NULL)
 		goto out;
@@ -133,19 +143,26 @@ struct pid_namespace *copy_pid_ns(unsigned long flags, struct pid_namespace *old
 	return create_pid_namespace(old_ns);
 }
 
-void free_pid_ns(struct kref *kref)
+static void free_pid_ns(struct kref *kref)
 {
-	struct pid_namespace *ns, *parent;
+	struct pid_namespace *ns;
 
 	ns = container_of(kref, struct pid_namespace, kref);
-
-	parent = ns->parent;
 	destroy_pid_namespace(ns);
+}
+
+void put_pid_ns(struct pid_namespace *ns)
+{
+	struct pid_namespace *parent;
 
-	if (parent != NULL)
-		put_pid_ns(parent);
+	while (ns != &init_pid_ns) {
+		parent = ns->parent;
+		if (!kref_put(&ns->kref, free_pid_ns))
+			break;
+		ns = parent;
+	}
 }
-EXPORT_SYMBOL_GPL(free_pid_ns);
+EXPORT_SYMBOL_GPL(put_pid_ns);
 
 void zap_pid_ns_processes(struct pid_namespace *pid_ns)
 {