4 files changed, 23 insertions, 3 deletions

diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index 928f2a5eedb7..d51e1bb781cf 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -221,8 +221,15 @@ static int fanotify_handle_event(struct fsnotify_group *group,
 
         event = fanotify_alloc_event(group, inode, mask, data);
         ret = -ENOMEM;
-        if (unlikely(!event))
+        if (unlikely(!event)) {
+                /*
+                 * We don't queue overflow events for permission events as
+                 * there the access is denied and so no event is in fact lost.
+                 */
+                if (!fanotify_is_perm_event(mask))
+                        fsnotify_queue_overflow(group);
                 goto finish;
+        }
 
         fsn_event = &event->fse;
         ret = fsnotify_add_event(group, fsn_event, fanotify_merge);
diff --git a/fs/notify/inotify/inotify_fsnotify.c b/fs/notify/inotify/inotify_fsnotify.c
index 8b73332735ba..40dedb37a1f3 100644
--- a/fs/notify/inotify/inotify_fsnotify.c
+++ b/fs/notify/inotify/inotify_fsnotify.c
@@ -99,8 +99,14 @@ int inotify_handle_event(struct fsnotify_group *group,
                               fsn_mark);
 
         event = kmalloc(alloc_len, GFP_KERNEL);
-        if (unlikely(!event))
+        if (unlikely(!event)) {
+                /*
+                 * Treat lost event due to ENOMEM the same way as queue
+                 * overflow to let userspace know event was lost.
+                 */
+                fsnotify_queue_overflow(group);
                 return -ENOMEM;
+        }
 
         fsn_event = &event->fse;
         fsnotify_init_event(fsn_event, inode, mask);
diff --git a/fs/notify/notification.c b/fs/notify/notification.c
index 66f85c651c52..3c3e36745f59 100644
--- a/fs/notify/notification.c
+++ b/fs/notify/notification.c
@@ -111,7 +111,8 @@ int fsnotify_add_event(struct fsnotify_group *group,
                 return 2;
         }
 
-        if (group->q_len >= group->max_events) {
+        if (event == group->overflow_event ||
+            group->q_len >= group->max_events) {
                 ret = 2;
                 /* Queue overflow event only if it isn't already queued */
                 if (!list_empty(&group->overflow_event->list)) {
diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index 067d52e95f02..9f1edb92c97e 100644
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h
@@ -331,6 +331,12 @@ extern int fsnotify_add_event(struct fsnotify_group *group,
                               struct fsnotify_event *event,
                               int (*merge)(struct list_head *,
                                            struct fsnotify_event *));
+/* Queue overflow event to a notification group */
+static inline void fsnotify_queue_overflow(struct fsnotify_group *group)
+{
+        fsnotify_add_event(group, group->overflow_event, NULL);
+}
+
 /* 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 */