@@ -70,8 +70,15 @@ static int fanotify_get_response_from_access(struct fsnotify_group *group,
wait_event(group->fanotify_data.access_waitq, event->response ||
atomic_read(&group->fanotify_data.bypass_perm));
- if (!event->response) /* bypass_perm set */
+ if (!event->response) { /* bypass_perm set */
+ /*
+ * Event was canceled because group is being destroyed. Remove
+ * it from group's event list because we are responsible for
+ * freeing the permission event.
+ */
+ fsnotify_remove_event(group, &event->fse);
return 0;
+ }
/* userspace responded, convert to something usable */
switch (event->response) {
@@ -385,6 +385,11 @@ static int fanotify_release(struct inode *ignored, struct file *file)
#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
struct fanotify_response_event *re, *lre;
+ /*
+ * There may be still new events arriving in the notification queue
+ * but since userspace cannot use fanotify fd anymore, no event can
+ * enter or leave access_list by now.
+ */
mutex_lock(&group->fanotify_data.access_mutex);
atomic_inc(&group->fanotify_data.bypass_perm);
@@ -400,6 +405,13 @@ static int fanotify_release(struct inode *ignored, struct file *file)
}
mutex_unlock(&group->fanotify_data.access_mutex);
+ /*
+ * Since bypass_perm is set, newly queued events will not wait for
+ * access response. Wake up the already sleeping ones now.
+ * synchronize_srcu() in fsnotify_destroy_group() will wait for all
+ * processes sleeping in fanotify_handle_event() waiting for access
+ * response and thus also for all permission events to be freed.
+ */
wake_up(&group->fanotify_data.access_waitq);
#endif
@@ -73,7 +73,8 @@ void fsnotify_destroy_event(struct fsnotify_group *group,
/* Overflow events are per-group and we don't want to free them */
if (!event || event->mask == FS_Q_OVERFLOW)
return;
-
+ /* If the event is still queued, we have a problem... */
+ WARN_ON(!list_empty(&event->list));
group->ops->free_event(event);
}
@@ -125,6 +126,21 @@ queue:
}
/*
+ * Remove @event from group's notification queue. It is the responsibility of
+ * the caller to destroy the event.
+ */
+void fsnotify_remove_event(struct fsnotify_group *group,
+ struct fsnotify_event *event)
+{
+ mutex_lock(&group->notification_mutex);
+ if (!list_empty(&event->list)) {
+ list_del_init(&event->list);
+ group->q_len--;
+ }
+ mutex_unlock(&group->notification_mutex);
+}
+
+/*
* Remove and return the first event from the notification list. It is the
* responsibility of the caller to destroy the obtained event
*/
@@ -326,6 +326,8 @@ extern int fsnotify_add_notify_event(struct fsnotify_group *group,
struct fsnotify_event *event,
int (*merge)(struct list_head *,
struct fsnotify_event *));
+/* Remove passed event from groups notification queue */
+extern void fsnotify_remove_event(struct fsnotify_group *group, struct fsnotify_event *event);
/* true if the group notification queue is empty */
extern bool fsnotify_notify_queue_is_empty(struct fsnotify_group *group);
/* return, but do not dequeue the first event on the notification queue */