diff --git a/net/sunrpc/svcauth_unix.c b/net/sunrpc/svcauth_unix.c
index 31a1bc60a5f6..1b5616a0b918 100644
--- a/net/sunrpc/svcauth_unix.c
+++ b/net/sunrpc/svcauth_unix.c
@@ -540,6 +540,13 @@ static int unix_gid_parse(struct cache_detail *cd,
 	if (ugp) {
 		struct cache_head *ch;
 		ug.h.flags = 0;
+		/*
+		 * mountd sends at least the user's primary group on
+		 * success, so an empty list can only mean the lookup
+		 * failed. Keep the credential's own groups instead.
+		 */
+		if (gids == 0)
+			set_bit(CACHE_NEGATIVE, &ug.h.flags);
 		ug.h.expiry_time = expiry;
 		ch = sunrpc_cache_update(cd,
 					 &ug.h, &ugp->h,