diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 0e5eda0..a3acf93 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -160,7 +160,7 @@
 	struct list_head fllink;
 
 	/* wakeup_source used when EPOLLWAKEUP is set */
-	struct wakeup_source *ws;
+	struct wakeup_source __rcu *ws;
 
 	/* The structure that describe the interested events and the source fd */
 	struct epoll_event event;
@@ -538,6 +538,38 @@
 	}
 }
 
+/* call only when ep->mtx is held */
+static inline struct wakeup_source *ep_wakeup_source(struct epitem *epi)
+{
+	return rcu_dereference_check(epi->ws, lockdep_is_held(&epi->ep->mtx));
+}
+
+/* call only when ep->mtx is held */
+static inline void ep_pm_stay_awake(struct epitem *epi)
+{
+	struct wakeup_source *ws = ep_wakeup_source(epi);
+
+	if (ws)
+		__pm_stay_awake(ws);
+}
+
+static inline bool ep_has_wakeup_source(struct epitem *epi)
+{
+	return rcu_access_pointer(epi->ws) ? true : false;
+}
+
+/* call when ep->mtx cannot be held (ep_poll_callback) */
+static inline void ep_pm_stay_awake_rcu(struct epitem *epi)
+{
+	struct wakeup_source *ws;
+
+	rcu_read_lock();
+	ws = rcu_dereference(epi->ws);
+	if (ws)
+		__pm_stay_awake(ws);
+	rcu_read_unlock();
+}
+
 /**
  * ep_scan_ready_list - Scans the ready list in a way that makes possible for
  *                      the scan code, to call f_op->poll(). Also allows for
@@ -601,7 +633,7 @@
 		 */
 		if (!ep_is_linked(&epi->rdllink)) {
 			list_add_tail(&epi->rdllink, &ep->rdllist);
-			__pm_stay_awake(epi->ws);
+			ep_pm_stay_awake(epi);
 		}
 	}
 	/*
@@ -670,7 +702,7 @@
 		list_del_init(&epi->rdllink);
 	spin_unlock_irqrestore(&ep->lock, flags);
 
-	wakeup_source_unregister(epi->ws);
+	wakeup_source_unregister(ep_wakeup_source(epi));
 
 	/* At this point it is safe to free the eventpoll item */
 	kmem_cache_free(epi_cache, epi);
@@ -754,7 +786,7 @@
 			 * callback, but it's not actually ready, as far as
 			 * caller requested events goes. We can remove it here.
 			 */
-			__pm_relax(epi->ws);
+			__pm_relax(ep_wakeup_source(epi));
 			list_del_init(&epi->rdllink);
 		}
 	}
@@ -986,7 +1018,7 @@
 	/* If this file is already in the ready list we exit soon */
 	if (!ep_is_linked(&epi->rdllink)) {
 		list_add_tail(&epi->rdllink, &ep->rdllist);
-		__pm_stay_awake(epi->ws);
+		ep_pm_stay_awake_rcu(epi);
 	}
 
 	/*
@@ -1148,6 +1180,7 @@
 static int ep_create_wakeup_source(struct epitem *epi)
 {
 	const char *name;
+	struct wakeup_source *ws;
 
 	if (!epi->ep->ws) {
 		epi->ep->ws = wakeup_source_register("eventpoll");
@@ -1156,17 +1189,29 @@
 	}
 
 	name = epi->ffd.file->f_path.dentry->d_name.name;
-	epi->ws = wakeup_source_register(name);
-	if (!epi->ws)
+	ws = wakeup_source_register(name);
+
+	if (!ws)
 		return -ENOMEM;
+	rcu_assign_pointer(epi->ws, ws);
 
 	return 0;
 }
 
-static void ep_destroy_wakeup_source(struct epitem *epi)
+/* rare code path, only used when EPOLL_CTL_MOD removes a wakeup source */
+static noinline void ep_destroy_wakeup_source(struct epitem *epi)
 {
-	wakeup_source_unregister(epi->ws);
-	epi->ws = NULL;
+	struct wakeup_source *ws = ep_wakeup_source(epi);
+
+	rcu_assign_pointer(epi->ws, NULL);
+
+	/*
+	 * wait for ep_pm_stay_awake_rcu to finish, synchronize_rcu is
+	 * used internally by wakeup_source_remove, too (called by
+	 * wakeup_source_unregister), so we cannot use call_rcu
+	 */
+	synchronize_rcu();
+	wakeup_source_unregister(ws);
 }
 
 /*
@@ -1201,7 +1246,7 @@
 		if (error)
 			goto error_create_wakeup_source;
 	} else {
-		epi->ws = NULL;
+		RCU_INIT_POINTER(epi->ws, NULL);
 	}
 
 	/* Initialize the poll table using the queue callback */
@@ -1249,7 +1294,7 @@
 	/* If the file is already "ready" we drop it inside the ready list */
 	if ((revents & event->events) && !ep_is_linked(&epi->rdllink)) {
 		list_add_tail(&epi->rdllink, &ep->rdllist);
-		__pm_stay_awake(epi->ws);
+		ep_pm_stay_awake(epi);
 
 		/* Notify waiting tasks that events are available */
 		if (waitqueue_active(&ep->wq))
@@ -1290,7 +1335,7 @@
 		list_del_init(&epi->rdllink);
 	spin_unlock_irqrestore(&ep->lock, flags);
 
-	wakeup_source_unregister(epi->ws);
+	wakeup_source_unregister(ep_wakeup_source(epi));
 
 error_create_wakeup_source:
 	kmem_cache_free(epi_cache, epi);
@@ -1319,9 +1364,9 @@
 	pt._key = event->events;
 	epi->event.data = event->data; /* protected by mtx */
 	if (epi->event.events & EPOLLWAKEUP) {
-		if (!epi->ws)
+		if (!ep_has_wakeup_source(epi))
 			ep_create_wakeup_source(epi);
-	} else if (epi->ws) {
+	} else if (ep_has_wakeup_source(epi)) {
 		ep_destroy_wakeup_source(epi);
 	}
 
@@ -1359,7 +1404,7 @@
 		spin_lock_irq(&ep->lock);
 		if (!ep_is_linked(&epi->rdllink)) {
 			list_add_tail(&epi->rdllink, &ep->rdllist);
-			__pm_stay_awake(epi->ws);
+			ep_pm_stay_awake(epi);
 
 			/* Notify waiting tasks that events are available */
 			if (waitqueue_active(&ep->wq))
@@ -1385,6 +1430,7 @@
 	unsigned int revents;
 	struct epitem *epi;
 	struct epoll_event __user *uevent;
+	struct wakeup_source *ws;
 	poll_table pt;
 
 	init_poll_funcptr(&pt, NULL);
@@ -1407,9 +1453,13 @@
 		 * instead, but then epi->ws would temporarily be out of sync
 		 * with ep_is_linked().
 		 */
-		if (epi->ws && epi->ws->active)
-			__pm_stay_awake(ep->ws);
-		__pm_relax(epi->ws);
+		ws = ep_wakeup_source(epi);
+		if (ws) {
+			if (ws->active)
+				__pm_stay_awake(ep->ws);
+			__pm_relax(ws);
+		}
+
 		list_del_init(&epi->rdllink);
 
 		pt._key = epi->event.events;
@@ -1426,7 +1476,7 @@
 			if (__put_user(revents, &uevent->events) ||
 			    __put_user(epi->event.data, &uevent->data)) {
 				list_add(&epi->rdllink, head);
-				__pm_stay_awake(epi->ws);
+				ep_pm_stay_awake(epi);
 				return eventcnt ? eventcnt : -EFAULT;
 			}
 			eventcnt++;
@@ -1446,7 +1496,7 @@
 				 * poll callback will queue them in ep->ovflist.
 				 */
 				list_add_tail(&epi->rdllink, &ep->rdllist);
-				__pm_stay_awake(epi->ws);
+				ep_pm_stay_awake(epi);
 			}
 		}
 	}