ipc/shm: do not use ipc_rcu_free() (66470b18) · Commits · 戴 / test

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/20170525185107.12869-7-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>

ipc/shm.c

+7 −2

Original line number	Diff line number	Diff line
		@@ -172,6 +172,11 @@ 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,
		@@ -179,7 +184,7 @@ static void shm_rcu_free(struct rcu_head *head)
		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;
		}

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