From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AE954C433F5 for ; Mon, 6 Sep 2021 12:44:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8DE4D60EE6 for ; Mon, 6 Sep 2021 12:44:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242180AbhIFMpl (ORCPT ); Mon, 6 Sep 2021 08:45:41 -0400 Received: from mail.kernel.org ([198.145.29.99]:50226 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242143AbhIFMpj (ORCPT ); Mon, 6 Sep 2021 08:45:39 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 1EA0460EE6; Mon, 6 Sep 2021 12:44:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1630932275; bh=2LXqSReT8SHF8LfIKml+aOLX7rlWLst/LYZu0lXukhc=; h=From:To:Cc:Subject:Date:From; b=OjIvZZYJAPvK97M3PpNaRASfWP7+Kp2/rLXGUbvB7ocH0/0q288viavvI91HA45EL aHiUIQjKJcvXh9KHxnn1Xe4XMtK7ETp3rLOqZcPktGEvuJuqkoPuCaQlbvNF/U1dt+ whuOL84Ga1APMLmhjpod1ZXJsBC1UBsJjr8aFZdBzeDSPAsTQx1FCcZCbUSYACyEBJ hyxJHVTYpPBbWUCLoVexSRzgOvRHR8Q+yFQ+84y4wXi2HnOl7S4PPPwKfKDjLuCL1K bSaHnN0B6zgZYM0fZU4LOgtbkC1b92kQtxtnVviFTvcswBaOkrq1wqs2SW6xbN66Hh z56w29WXYR2MQ== Received: from johan by xi with local (Exim 4.94.2) (envelope-from ) id 1mNDz3-0005ny-Rk; Mon, 06 Sep 2021 14:44:22 +0200 From: Johan Hovold To: Oliver Neukum , Greg Kroah-Hartman Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Johan Hovold , stable@vger.kernel.org, Jaejoong Kim Subject: [PATCH] USB: cdc-acm: fix minor-number release Date: Mon, 6 Sep 2021 14:43:39 +0200 Message-Id: <20210906124339.22264-1-johan@kernel.org> X-Mailer: git-send-email 2.32.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If the driver runs out of minor numbers it would release minor 0 and allow another device to claim the minor while still in use. Fortunately, registering the tty class device of the second device would fail (with a stack dump) due to the sysfs name collision so no memory is leaked. Fixes: cae2bc768d17 ("usb: cdc-acm: Decrement tty port's refcount if probe() fail") Cc: stable@vger.kernel.org # 4.19 Cc: Jaejoong Kim Signed-off-by: Johan Hovold --- drivers/usb/class/cdc-acm.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c index 4895325b16a4..5f0260bc4469 100644 --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -726,7 +726,8 @@ static void acm_port_destruct(struct tty_port *port) { struct acm *acm = container_of(port, struct acm, port); - acm_release_minor(acm); + if (acm->minor != ACM_TTY_MINORS) + acm_release_minor(acm); usb_put_intf(acm->control); kfree(acm->country_codes); kfree(acm); @@ -1323,8 +1324,10 @@ static int acm_probe(struct usb_interface *intf, usb_get_intf(acm->control); /* undone in destruct() */ minor = acm_alloc_minor(acm); - if (minor < 0) + if (minor < 0) { + acm->minor = ACM_TTY_MINORS; goto err_put_port; + } acm->minor = minor; acm->dev = usb_dev; -- 2.32.0