--- base/allocator/partition_allocator/page_allocator.cc.orig
+++ base/allocator/partition_allocator/page_allocator.cc
@@ -17,6 +17,11 @@
 #include <errno.h>
 #include <sys/mman.h>
 
+#if defined(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