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, 3 insertions, 3 deletions

diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index 89a27e8b17fb..d055d987850c 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -34,7 +34,7 @@ static struct user_namespace *clone_user_ns(struct user_namespace *old_ns)
 
         ns = kmalloc(sizeof(struct user_namespace), GFP_KERNEL);
         if (!ns)
-                return NULL;
+                return ERR_PTR(-ENOMEM);
 
         kref_init(&ns->kref);
 
@@ -45,7 +45,7 @@ static struct user_namespace *clone_user_ns(struct user_namespace *old_ns)
         ns->root_user = alloc_uid(ns, 0);
         if (!ns->root_user) {
                 kfree(ns);
-                return NULL;
+                return ERR_PTR(-ENOMEM);
         }
 
         /* Reset current->user with a new one */
@@ -53,7 +53,7 @@ static struct user_namespace *clone_user_ns(struct user_namespace *old_ns)
         if (!new_user) {
                 free_uid(ns->root_user);
                 kfree(ns);
-                return NULL;
+                return ERR_PTR(-ENOMEM);
         }
 
         switch_uid(new_user);