Index: src/third_party/mozjs/extract/js/src/vm/ArrayBufferObject.cpp
--- src/third_party/mozjs/extract/js/src/vm/ArrayBufferObject.cpp.orig
+++ src/third_party/mozjs/extract/js/src/vm/ArrayBufferObject.cpp
@@ -278,7 +278,7 @@ bool js::ExtendBufferMapping(void* dataPointer, size_t
   return true;
 #elif defined(__wasi__)
   return false;
-#elif defined(XP_LINUX)
+#elif defined(XP_LINUX) && !defined(__OpenBSD__)
   // Note this will not move memory (no MREMAP_MAYMOVE specified)
   if (MAP_FAILED == mremap(dataPointer, mappedSize, newMappedSize, 0)) {
     return false;
