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]>
This commit is contained in:
Kees Cook 2017-07-12 14:34:53 -07:00 • committed by Linus Torvalds
commit 66470b1817

View file

@ -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;
}