3 files changed, 17 insertions, 7 deletions

diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index 6702a6a0bbb5..928f2a5eedb7 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -139,23 +139,32 @@ static bool fanotify_should_send_event(struct fsnotify_mark *inode_mark,
         return false;
 }
 
-struct fanotify_event_info *fanotify_alloc_event(struct inode *inode, u32 mask,
+struct fanotify_event_info *fanotify_alloc_event(struct fsnotify_group *group,
+                                                 struct inode *inode, u32 mask,
                                                  const struct path *path)
 {
         struct fanotify_event_info *event;
+        gfp_t gfp = GFP_KERNEL;
+
+        /*
+         * For queues with unlimited length lost events are not expected and
+         * can possibly have security implications. Avoid losing events when
+         * memory is short.
+         */
+        if (group->max_events == UINT_MAX)
+                gfp |= __GFP_NOFAIL;
 
         if (fanotify_is_perm_event(mask)) {
                 struct fanotify_perm_event_info *pevent;
 
-                pevent = kmem_cache_alloc(fanotify_perm_event_cachep,
-                                          GFP_KERNEL);
+                pevent = kmem_cache_alloc(fanotify_perm_event_cachep, gfp);
                 if (!pevent)
                         return NULL;
                 event = &pevent->fae;
                 pevent->response = 0;
                 goto init;
         }
-        event = kmem_cache_alloc(fanotify_event_cachep, GFP_KERNEL);
+        event = kmem_cache_alloc(fanotify_event_cachep, gfp);
         if (!event)
                 return NULL;
 init: __maybe_unused
@@ -210,7 +219,7 @@ static int fanotify_handle_event(struct fsnotify_group *group,
                         return 0;
         }
 
-        event = fanotify_alloc_event(inode, mask, data);
+        event = fanotify_alloc_event(group, inode, mask, data);
         ret = -ENOMEM;
         if (unlikely(!event))
                 goto finish;
diff --git a/fs/notify/fanotify/fanotify.h b/fs/notify/fanotify/fanotify.h
index 256d9d1ddea9..8609ba06f474 100644
--- a/fs/notify/fanotify/fanotify.h
+++ b/fs/notify/fanotify/fanotify.h
@@ -52,5 +52,6 @@ static inline struct fanotify_event_info *FANOTIFY_E(struct fsnotify_event *fse)
         return container_of(fse, struct fanotify_event_info, fse);
 }
 
-struct fanotify_event_info *fanotify_alloc_event(struct inode *inode, u32 mask,
+struct fanotify_event_info *fanotify_alloc_event(struct fsnotify_group *group,
+                                                 struct inode *inode, u32 mask,
                                                  const struct path *path);
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index c07eb3d655ea..72e367822efb 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -757,7 +757,7 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags)
         group->fanotify_data.user = user;
         atomic_inc(&user->fanotify_listeners);
 
-        oevent = fanotify_alloc_event(NULL, FS_Q_OVERFLOW, NULL);
+        oevent = fanotify_alloc_event(group, NULL, FS_Q_OVERFLOW, NULL);
         if (unlikely(!oevent)) {
                 fd = -ENOMEM;
                 goto out_destroy_group;