diff --git a/sys/fs/nfsclient/nfs_clkdtrace.c b/sys/fs/nfsclient/nfs_clkdtrace.c
index 367153e4beef..7a1281524401 100644
--- a/sys/fs/nfsclient/nfs_clkdtrace.c
+++ b/sys/fs/nfsclient/nfs_clkdtrace.c
@@ -541,7 +541,7 @@ dtnfsclient_load(void *dummy)
 }
 
 static int
-dtnfsclient_unload()
+dtnfsclient_unload(void)
 {
 
 	dtrace_nfscl_nfs234_start_probe = NULL;