From 5c2320f113402b7450e01e2093286663adf27ecc Mon Sep 17 00:00:00 2001
From: Sam Lantinga <slouken@libsdl.org>
Date: Fri, 7 Oct 2016 17:58:02 -0700
Subject: [PATCH] Fixed bug 3022 - SDL_UnlockMutex(SDL_EventQ.lock) in
 SDL_PeepEvents can cause error when lock is null

---
 src/events/SDL_events.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/events/SDL_events.c b/src/events/SDL_events.c
index 0af027045..2f5b0af29 100644
--- a/src/events/SDL_events.c
+++ b/src/events/SDL_events.c
@@ -332,7 +332,9 @@ SDL_PeepEvents(SDL_Event * events, int numevents, SDL_eventaction action,
                 }
             }
         }
-        SDL_UnlockMutex(SDL_EventQ.lock);
+        if (SDL_EventQ.lock) {
+            SDL_UnlockMutex(SDL_EventQ.lock);
+        }
     } else {
         return SDL_SetError("Couldn't lock event queue");
     }
@@ -374,7 +376,7 @@ SDL_FlushEvents(Uint32 minType, Uint32 maxType)
 #endif
 
     /* Lock the event queue */
-    if (SDL_LockMutex(SDL_EventQ.lock) == 0) {
+    if (SDL_EventQ.lock && SDL_LockMutex(SDL_EventQ.lock) == 0) {
         SDL_EventEntry *entry, *next;
         Uint32 type;
         for (entry = SDL_EventQ.head; entry; entry = next) {