diff --git a/include/link.h b/include/link.h
index 2e23d20c7c4ede4ecaf5bf71e408e1d86982fb11..32d158428de29d3f11d223f3e883e5af79b64c73 100644
--- a/include/link.h
+++ b/include/link.h
@@ -500,7 +500,7 @@ vlong	setuint32(Link *ctxt, LSym *s, vlong r, uint32 v);
 vlong	setuint64(Link *ctxt, LSym *s, vlong r, uint64 v);
 vlong	setuint8(Link *ctxt, LSym *s, vlong r, uint8 v);
 vlong	setuintxx(Link *ctxt, LSym *s, vlong off, uint64 v, vlong wid);
-void	symgrow(Link *ctxt, LSym *s, int32 siz);
+void	symgrow(Link *ctxt, LSym *s, vlong siz);
 
 // go.c
 void	double2ieee(uint64 *ieee, double native);
diff --git a/src/liblink/data.c b/src/liblink/data.c
index 9a481b6e5e6d65820088999d8b87f537173c7f71..58d6d6b5e8f58eb66cb54d89531a479b72f59ca9 100644
--- a/src/liblink/data.c
+++ b/src/liblink/data.c
@@ -41,10 +41,16 @@ mangle(char *file)
 }
 
 void
-symgrow(Link *ctxt, LSym *s, int32 siz)
+symgrow(Link *ctxt, LSym *s, vlong lsiz)
 {
+	int32 siz;
+
 	USED(ctxt);
 
+	siz = (int32)lsiz;
+	if((vlong)siz != lsiz)
+		sysfatal("symgrow size %lld too long", lsiz);
+
 	if(s->np >= siz)
 		return;