ipc/msg: do not use ipc_rcu_free()

Avoid using ipc_rcu_free, since it just re-finds the original structure
pointer.  For the pre-list-init failure path, there is no RCU needed,
since it was just allocated.  It can be directly freed.

Link: http://lkml.kernel.org/r/20170525185107.12869-8-manfred@colorfullife.com
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/ipc/msg.c b/ipc/msg.c
index 0ed7dae7d4e8b4ba27e06a930362e898bcc94119..25d43e27ef12cd6d253bbbca733f0650929276a2 100644 (file)
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -95,13 +95,18 @@ static inline void msg_rmid(struct ipc_namespace *ns, struct msg_queue *s)
        ipc_rmid(&msg_ids(ns), &s->q_perm);
 }
 
+static void __msg_free(struct msg_queue *msq)
+{
+       kvfree(msq);
+}
+
 static void msg_rcu_free(struct rcu_head *head)
 {
        struct kern_ipc_perm *p = container_of(head, struct kern_ipc_perm, rcu);
        struct msg_queue *msq = container_of(p, struct msg_queue, q_perm);
 
        security_msg_queue_free(msq);
-       ipc_rcu_free(head);
+       __msg_free(msq);
 }
 
 /**
@@ -131,7 +136,7 @@ static int newque(struct ipc_namespace *ns, struct ipc_params *params)
        msq->q_perm.security = NULL;
        retval = security_msg_queue_alloc(msq);
        if (retval) {
-               ipc_rcu_putref(&msq->q_perm, ipc_rcu_free);
+               __msg_free(msq);
                return retval;
        }