ipc/sem: 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/20170525185107.12869-6-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/sem.c b/ipc/sem.c
index 484ccf83cf856469e0f0bfb610a3d0564b0e4e6e..a04c4d6d120cedae174cfad1ecf872270860e01c 100644 (file)
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -258,13 +258,18 @@ static void merge_queues(struct sem_array *sma)
        }
 }
 
+static void __sem_free(struct sem_array *sma)
+{
+       kvfree(sma);
+}
+
 static void sem_rcu_free(struct rcu_head *head)
 {
        struct kern_ipc_perm *p = container_of(head, struct kern_ipc_perm, rcu);
        struct sem_array *sma = container_of(p, struct sem_array, sem_perm);
 
        security_sem_free(sma);
-       ipc_rcu_free(head);
+       __sem_free(sma);
 }
 
 /*
@@ -482,7 +487,7 @@ static int newary(struct ipc_namespace *ns, struct ipc_params *params)
        sma->sem_perm.security = NULL;
        retval = security_sem_alloc(sma);
        if (retval) {
-               ipc_rcu_putref(&sma->sem_perm, ipc_rcu_free);
+               __sem_free(sma);
                return retval;
        }