fix create_new_namespaces() return value

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().

Modify create_new_namespaces() to also use the errors returned by the
copy_*_ns routines and not to systematically return ENOMEM.

[oleg@tv-sign.ru: better changelog]
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Cc: Serge E. Hallyn <serue@us.ibm.com>
Cc: Badari Pulavarty <pbadari@us.ibm.com>
Cc: Pavel Emelianov <xemul@openvz.org>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 6 insertions, 4 deletions

diff --git a/kernel/utsname.c b/kernel/utsname.c
index 160c8c5136bd..3ae43936bd88 100644
--- a/kernel/utsname.c
+++ b/kernel/utsname.c
@@ -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_ns(struct uts_namespace *old_ns)
         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;
 }