ipc/shm: 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/[email protected] Signed-off-by: Kees Cook <[email protected]> Signed-off-by: Manfred Spraul <[email protected]> Cc: Davidlohr Bueso <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
umac211 · Jul 12, 2017 · 66470b1 · 66470b1
1 parent 1b4654e
commit 66470b1
Showing 1 changed file with 7 additions and 2 deletions.
diff --git a/ipc/shm.c b/ipc/shm.c
@@ -172,14 +172,19 @@ static inline void shm_lock_by_ptr(struct shmid_kernel *ipcp)
 	ipc_lock_object(&ipcp->shm_perm);
 }
 
+static void __shm_free(struct shmid_kernel *shp)
+{
+	kvfree(shp);
+}
+
 static void shm_rcu_free(struct rcu_head *head)
 {
 	struct kern_ipc_perm *ptr = container_of(head, struct kern_ipc_perm,
 							rcu);
 	struct shmid_kernel *shp = container_of(ptr, struct shmid_kernel,
 							shm_perm);
 	security_shm_free(shp);
-	ipc_rcu_free(head);
+	__shm_free(shp);
 }
 
 static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
@@ -557,7 +562,7 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
 	shp->shm_perm.security = NULL;
 	error = security_shm_alloc(shp);
 	if (error) {
-		ipc_rcu_putref(&shp->shm_perm, ipc_rcu_free);
+		__shm_free(shp);
 		return error;
 	}