diff --git a/js/src/assembler/assembler/LinkBuffer.h b/js/src/assembler/assembler/LinkBuffer.h
index 3f51ab371c6..57af1eda1f9 100644
--- a/js/src/assembler/assembler/LinkBuffer.h
+++ b/js/src/assembler/assembler/LinkBuffer.h
@@ -192,6 +192,11 @@ public:
         return CodeLocationLabel(code());
     }
 
+    // Useful as a proxy to detect OOM.
+    void* unsafeCode() {
+        return code();
+    }
+
 protected:
     // Keep this private! - the underlying code should only be obtained externally via 
     // finalizeCode() or finalizeCodeAddendum().
diff --git a/js/src/yarr/YarrJIT.cpp b/js/src/yarr/YarrJIT.cpp
index f5585856dc0..2007addf2cf 100644
--- a/js/src/yarr/YarrJIT.cpp
+++ b/js/src/yarr/YarrJIT.cpp
@@ -2688,10 +2688,16 @@ public:
         backtrack();
 
         // Link & finalize the code.
-        // XXX yarr-oom
         ExecutablePool *pool;
         bool ok;
         LinkBuffer linkBuffer(this, globalData->regexAllocator, &pool, &ok, REGEXP_CODE);
+
+        // Attempt to detect OOM during linkBuffer creation.
+        if (linkBuffer.unsafeCode() == nullptr) {
+            jitObject.setFallBack(true);
+            return;
+        }
+
         m_backtrackingState.linkDataLabels(linkBuffer);
 
         if (compileMode == MatchOnly) {