diff --git a/fs/nfs/fs_context.c b/fs/nfs/fs_context.c
index d60c086c6e9c7286a415aeee9adf150debe25384..7e21a0ce78d6d3176bca4dcc1f4da6067bb0ba0a 100644
--- a/fs/nfs/fs_context.c
+++ b/fs/nfs/fs_context.c
@@ -637,6 +637,8 @@ static int nfs_fs_context_parse_param(struct fs_context *fc,
 			return ret;
 		break;
 	case Opt_vers:
+		if (!param->string)
+			goto out_invalid_value;
 		ret = nfs_parse_version_string(fc, param->string);
 		if (ret < 0)
 			return ret;
@@ -648,6 +650,8 @@ static int nfs_fs_context_parse_param(struct fs_context *fc,
 		break;
 
 	case Opt_proto:
+		if (!param->string)
+			goto out_invalid_value;
 		protofamily = AF_INET;
 		switch (lookup_constant(nfs_xprt_protocol_tokens, param->string, -1)) {
 		case Opt_xprt_udp6:
@@ -681,6 +685,8 @@ static int nfs_fs_context_parse_param(struct fs_context *fc,
 		break;
 
 	case Opt_mountproto:
+		if (!param->string)
+			goto out_invalid_value;
 		mountfamily = AF_INET;
 		switch (lookup_constant(nfs_xprt_protocol_tokens, param->string, -1)) {
 		case Opt_xprt_udp6: