[Devel] [PATCH] create_new_namespaces: fix improper return of NULL

[Oleg Nesterov]

Untested.

dup_mnt_ns() and clone_uts_ns() return NULL on failure. This is wrong,
create_new_namespaces() uses ERR_PTR() to catch an error. This means
that the subsequent create_new_namespaces() will hit BUG_ON() in
copy_mnt_ns() or copy_utsname().

Signed-off-by: Oleg Nesterov <oleg at tv-sign.ru>

--- ns/fs/namespace.c~1_NS_NULL	2007-05-21 13:57:56.000000000 +0400
+++ ns/fs/namespace.c	2007-06-19 17:26:35.000000000 +0400
@@ -1457,7 +1457,7 @@ static struct mnt_namespace *dup_mnt_ns(
 
 	new_ns = kmalloc(sizeof(struct mnt_namespace), GFP_KERNEL);
 	if (!new_ns)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 
 	atomic_set(&new_ns->count, 1);
 	INIT_LIST_HEAD(&new_ns->list);
@@ -1471,7 +1471,7 @@ static struct mnt_namespace *dup_mnt_ns(
 	if (!new_ns->root) {
 		up_write(&namespace_sem);
 		kfree(new_ns);
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 	}
 	spin_lock(&vfsmount_lock);
 	list_add_tail(&new_ns->list, &new_ns->root->mnt_list);
--- ns/kernel/utsname.c~1_NS_NULL	2007-05-21 13:57:59.000000000 +0400
+++ ns/kernel/utsname.c	2007-06-19 17:35:22.000000000 +0400
@@ -13,6 +13,7 @@
 #include <linux/uts.h>
 #include <linux/utsname.h>
 #include <linux/version.h>
+#include <linux/err.h>
 
 /*
  * Clone a new ns copying an original utsname, setting refcount to 1
@@ -24,10 +25,11 @@ static struct uts_namespace *clone_uts_n
 	struct uts_namespace *ns;
 
 	ns = kmalloc(sizeof(struct uts_namespace), GFP_KERNEL);
-	if (ns) {
-		memcpy(&ns->name, &old_ns->name, sizeof(ns->name));
-		kref_init(&ns->kref);
-	}
+	if (!ns)
+		return ERR_PTR(-ENOMEM);
+
+	memcpy(&ns->name, &old_ns->name, sizeof(ns->name));
+	kref_init(&ns->kref);
 	return ns;
 }
 

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