Index: sys/kern/vfs_mount.c
===================================================================
--- sys/kern/vfs_mount.c
+++ sys/kern/vfs_mount.c
@@ -2562,10 +2562,18 @@
 		return;
 	sbuf_printf(sb, " %s=\"", what);
 	TAILQ_FOREACH(opt, opts, link) {
-		if (opt->name[0] == '\0' || (opt->len > 0 && *(char *)opt->value == '\0'))
+		if (opt->name[0] == '\0')
 			continue;
 		devctl_safe_quote_sb(sb, opt->name);
-		if (opt->len > 0) {
+		/*
+		 * Only print the option values for those options that are known
+		 * to be ascii strings. Many others are, but we cannot assume
+		 * that here.
+		 */
+		if (opt->len > 1 &&
+		    (strcmp(opt->name, "fstype") == 0 ||
+		     strcmp(opt->name, "fspath") == 0 ||
+		     strcmp(opt->name, "from") == 0)) {
 			sbuf_putc(sb, '=');
 			devctl_safe_quote_sb(sb, opt->value);
 		}