1 files changed, 20 insertions, 1 deletions
diff --git a/rts/eventlog/EventLogWriter.c b/rts/eventlog/EventLogWriter.c
index b19e617a4c..5387f932eb 100644
--- a/rts/eventlog/EventLogWriter.c
+++ b/rts/eventlog/EventLogWriter.c
@@ -28,6 +28,17 @@ static pid_t event_log_pid = -1;
 // File for logging events
 static FILE *event_log_file = NULL;
 
+#if defined(THREADED_RTS)
+// Protects event_log_file
+static Mutex event_log_mutex;
+
+static void acquire_event_log_lock(void) { ACQUIRE_LOCK(&event_log_mutex); }
+static void release_event_log_lock(void) { RELEASE_LOCK(&event_log_mutex); }
+#else
+static void acquire_event_log_lock(void) {}
+static void release_event_log_lock(void) {}
+#endif
+
 static void initEventLogFileWriter(void);
 static bool writeEventLogFile(void *eventlog, size_t eventlog_size);
 static void flushEventLogFile(void);
@@ -89,6 +100,9 @@ initEventLogFileWriter(void)
     }
 
     stgFree(event_log_filename);
+#if defined(THREADED_RTS)
+    initMutex(&event_log_mutex);
+#endif
 }
 
 static bool
@@ -97,15 +111,17 @@ writeEventLogFile(void *eventlog, size_t eventlog_size)
     unsigned char *begin = eventlog;
     size_t remain = eventlog_size;
 
+    acquire_event_log_lock();
     while (remain > 0) {
         size_t written = fwrite(begin, 1, remain, event_log_file);
         if (written == 0) {
+            release_event_log_lock();
             return false;
         }
         remain -= written;
         begin += written;
     }
-
+    release_event_log_lock();
     return true;
 }
 
@@ -124,6 +140,9 @@ stopEventLogFileWriter(void)
         fclose(event_log_file);
         event_log_file = NULL;
     }
+#if defined(THREADED_RTS)
+    closeMutex(&event_log_mutex);
+#endif
 }
 
 const EventLogWriter FileEventLogWriter = {