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Diffstat (limited to 'ipc/shm.c')
-rw-r--r--ipc/shm.c67
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);
}