diff --git a/fs/coredump.c b/fs/coredump.c
index e3ad709a4232..0b2528fb640e 100644
--- a/fs/coredump.c
+++ b/fs/coredump.c
@@ -73,10 +73,15 @@ static int expand_corename(struct core_name *cn, int size)
 static int cn_vprintf(struct core_name *cn, const char *fmt, va_list arg)
 {
 	int free, need;
+	va_list arg_copy;
 
 again:
 	free = cn->size - cn->used;
-	need = vsnprintf(cn->corename + cn->used, free, fmt, arg);
+
+	va_copy(arg_copy, arg);
+	need = vsnprintf(cn->corename + cn->used, free, fmt, arg_copy);
+	va_end(arg_copy);
+
 	if (need < free) {
 		cn->used += need;
 		return 0;