diff --git a/libtcmu_config.c b/libtcmu_config.c

index 895b712..a17e74d 100644

--- a/libtcmu_config.c

+++ b/libtcmu_config.c

@@ -202,7 +202,7 @@ static int tcmu_read_config(int fd, char *buf, int count)

 	do {

 		len = read(fd, buf, count);

-	} while (errno == EAGAIN);

+	} while (len < 0 && errno == EAGAIN);

 	errno = save;

 	return len;