diff --git a/arch/um/drivers/virtio_uml.c b/arch/um/drivers/virtio_uml.c
index 515d648d3c3d34d7f71c55bc63b6e7d41f15e107..ef620caed8e7ba79250e1c3b65d2de57b438198e 100644
--- a/arch/um/drivers/virtio_uml.c
+++ b/arch/um/drivers/virtio_uml.c
@@ -97,6 +97,9 @@ static int full_read(int fd, void *buf, int len, bool abortable)
 {
 	int rc;
 
+	if (!len)
+		return 0;
+
 	do {
 		rc = os_read_file(fd, buf, len);
 		if (rc > 0) {