--- a/third_party/WebKit/Source/wtf/allocator/PageAllocator.cpp	
+++ a/third_party/WebKit/Source/wtf/allocator/PageAllocator.cpp	
@@ -41,6 +41,11 @@ 
 #include <errno.h>
 #include <sys/mman.h>
 
+#if OS(LINUX) && defined(MADV_FREE)
+// Added in Linux 4.5, but it breaks the sandbox.
+#undef MADV_FREE
+#endif
+
 #ifndef MADV_FREE
 #define MADV_FREE MADV_DONTNEED
 #endif