diff --git a/sys/src/libmach/map.c b/sys/src/libmach/map.c
old mode 100644
new mode 100755
index c745d82a6..c668defd1
--- a/sys/src/libmach/map.c
+++ b/sys/src/libmach/map.c
@@ -89,11 +89,13 @@ attachproc(int pid, int kflag, int corefd, Fhdr *fp)
 	map = newmap(0, 4);
 	if (!map)
 		return 0;
-	if(kflag)
+	if(kflag) {
 		regs = "kregs";
-	else
+		mode = OREAD;
+	} else {
 		regs = "regs";
-	mode = ORDWR;
+		mode = ORDWR;
+	}
 	if (mach->regsize) {
 		sprint(buf, "/proc/%d/%s", pid, regs);
 		fd = open(buf, mode);