diff --git a/sbin/fdisk/fdisk.c b/sbin/fdisk/fdisk.c
index 5f1b5f97ca8c..e10929a54890 100644
--- a/sbin/fdisk/fdisk.c
+++ b/sbin/fdisk/fdisk.c
@@ -1342,7 +1342,7 @@ get_rootdisk(void)
 	if (statfs("/", &rootfs) == -1)
 		err(1, "statfs(\"/\")");
 
-	if ((rv = regcomp(&re, "^(/dev/.*)(\\d+(s\\d+)?[a-h])?$",
+	if ((rv = regcomp(&re, "^(/dev/[a-z]+[0-9]+)([sp][0-9]+)?[a-h]?$",
 		    REG_EXTENDED)) != 0)
 		errx(1, "regcomp() failed (%d)", rv);
 	if ((rv = regexec(&re, rootfs.f_mntfromname, NMATCHES, rm, 0)) != 0)