fix freeing user_struct in user cache
When racing on adding into user cache, the new allocated from mm slab
is freed without putting user namespace.
Since the user namespace is already operated by getting, putting has
to be issued.
Signed-off-by: Hillf Danton <dhillf@gmail.com>
Acked-by: Serge Hallyn <serge@hallyn.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/kernel/user.c b/kernel/user.c
index 2c7d8d5..5c598ca 100644
--- a/kernel/user.c
+++ b/kernel/user.c
@@ -158,6 +158,7 @@
spin_lock_irq(&uidhash_lock);
up = uid_hash_find(uid, hashent);
if (up) {
+ put_user_ns(ns);
key_put(new->uid_keyring);
key_put(new->session_keyring);
kmem_cache_free(uid_cachep, new);