diff options
| -rw-r--r-- | ipc/shm.c | 67 |
1 files changed, 35 insertions, 32 deletions
diff --git a/ipc/shm.c b/ipc/shm.c index 1fc3a61b443b..7fc9f9f3a26b 100644 --- a/ipc/shm.c +++ b/ipc/shm.c @@ -269,32 +269,6 @@ static void shm_close(struct vm_area_struct *vma) } /* Called with ns->shm_ids(ns).rwsem locked */ -static void shm_mark_orphan(struct shmid_kernel *shp, struct ipc_namespace *ns) -{ - if (WARN_ON(shp->shm_creator != current)) /* Remove me when it works */ - return; - - /* - * Mark it as orphaned to destroy the segment when - * kernel.shm_rmid_forced is changed. - * It is noop if the following shm_may_destroy() returns true. - */ - shp->shm_creator = NULL; - - /* - * Don't even try to destroy it. If shm_rmid_forced=0 and IPC_RMID - * is not set, it shouldn't be deleted here. - */ - if (!ns->shm_rmid_forced) - return; - - if (shm_may_destroy(ns, shp)) { - shm_lock_by_ptr(shp); - shm_destroy(ns, shp); - } -} - -/* Called with ns->shm_ids(ns).rwsem locked */ static int shm_try_destroy_orphaned(int id, void *p, void *data) { struct ipc_namespace *ns = data; @@ -325,20 +299,49 @@ void shm_destroy_orphaned(struct ipc_namespace *ns) up_write(&shm_ids(ns).rwsem); } - +/* Locking assumes this will only be called with task == current */ void exit_shm(struct task_struct *task) { struct ipc_namespace *ns = task->nsproxy->ipc_ns; struct shmid_kernel *shp, *n; - if (shm_ids(ns).in_use == 0) + if (list_empty(&task->sysvshm.shm_clist)) + return; + + /* + * If kernel.shm_rmid_forced is not set then only keep track of + * which shmids are orphaned, so that a later set of the sysctl + * can clean them up. + */ + if (!ns->shm_rmid_forced) { + down_read(&shm_ids(ns).rwsem); + list_for_each_entry(shp, &task->sysvshm.shm_clist, shm_clist) + shp->shm_creator = NULL; + /* + * Only under read lock but we are only called on current + * so no entry on the list will be shared. + */ + list_del(&task->sysvshm.shm_clist); + up_read(&shm_ids(ns).rwsem); return; + } - /* Destroy all already created segments, but not mapped yet */ + /* + * Destroy all already created segments, that were not yet mapped, + * and mark any mapped as orphan to cover the sysctl toggling. + * Destroy is skipped if shm_may_destroy() returns false. + */ down_write(&shm_ids(ns).rwsem); - list_for_each_entry_safe(shp, n, &task->sysvshm.shm_clist, shm_clist) - shm_mark_orphan(shp, ns); - /* remove the list head from any segments still attached */ + list_for_each_entry_safe(shp, n, &task->sysvshm.shm_clist, shm_clist) { + shp->shm_creator = NULL; + + if (shm_may_destroy(ns, shp)) { + shm_lock_by_ptr(shp); + shm_destroy(ns, shp); + } + } + + /* Remove the list head from any segments still attached. */ list_del(&task->sysvshm.shm_clist); up_write(&shm_ids(ns).rwsem); } |