diff options
Diffstat (limited to 'ipc/shm.c')
| -rw-r--r-- | ipc/shm.c | 23 |
1 files changed, 17 insertions, 6 deletions
diff --git a/ipc/shm.c b/ipc/shm.c index e7d51072d1c..c6b4ad5ce3b 100644 --- a/ipc/shm.c +++ b/ipc/shm.c @@ -757,31 +757,42 @@ static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd, return -EFAULT; } + down_write(&shm_ids(ns).rw_mutex); + rcu_read_lock(); + ipcp = ipcctl_pre_down(ns, &shm_ids(ns), shmid, cmd, &shmid64.shm_perm, 0); - if (IS_ERR(ipcp)) - return PTR_ERR(ipcp); + if (IS_ERR(ipcp)) { + err = PTR_ERR(ipcp); + /* the ipc lock is not held upon failure */ + goto out_unlock1; + } shp = container_of(ipcp, struct shmid_kernel, shm_perm); err = security_shm_shmctl(shp, cmd); if (err) - goto out_unlock; + goto out_unlock0; + switch (cmd) { case IPC_RMID: + /* do_shm_rmid unlocks the ipc object and rcu */ do_shm_rmid(ns, ipcp); goto out_up; case IPC_SET: err = ipc_update_perm(&shmid64.shm_perm, ipcp); if (err) - goto out_unlock; + goto out_unlock0; shp->shm_ctim = get_seconds(); break; default: err = -EINVAL; } -out_unlock: - shm_unlock(shp); + +out_unlock0: + ipc_unlock_object(&shp->shm_perm); +out_unlock1: + rcu_read_unlock(); out_up: up_write(&shm_ids(ns).rw_mutex); return err; |