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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 B445BC3A5A2 for ; Fri, 20 Sep 2019 14:33:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 921C6206C2 for ; Fri, 20 Sep 2019 14:33:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391493AbfITOdN (ORCPT ); Fri, 20 Sep 2019 10:33:13 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:36396 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388255AbfITOZI (ORCPT ); Fri, 20 Sep 2019 10:25:08 -0400 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1iBJqM-0004y2-FS; Fri, 20 Sep 2019 15:25:06 +0100 Received: from ben by deadeye with local (Exim 4.92.1) (envelope-from ) id 1iBJqH-0007yc-B1; Fri, 20 Sep 2019 15:25:01 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "Mauro Carvalho Chehab" , "Oliver Neukum" , "Hans Verkuil" , syzbot+0c90fc937c84f97d0aa6@syzkaller.appspotmail.com Date: Fri, 20 Sep 2019 15:23:35 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 117/132] media: cpia2_usb: first wake up, then free in disconnect In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.74-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Oliver Neukum commit eff73de2b1600ad8230692f00bc0ab49b166512a upstream. Kasan reported a use after free in cpia2_usb_disconnect() It first freed everything and then woke up those waiting. The reverse order is correct. Fixes: 6c493f8b28c67 ("[media] cpia2: major overhaul to get it in a working state again") Signed-off-by: Oliver Neukum Reported-by: syzbot+0c90fc937c84f97d0aa6@syzkaller.appspotmail.com Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Ben Hutchings --- drivers/media/usb/cpia2/cpia2_usb.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/media/usb/cpia2/cpia2_usb.c +++ b/drivers/media/usb/cpia2/cpia2_usb.c @@ -884,7 +884,6 @@ static void cpia2_usb_disconnect(struct cpia2_unregister_camera(cam); v4l2_device_disconnect(&cam->v4l2_dev); mutex_unlock(&cam->v4l2_lock); - v4l2_device_put(&cam->v4l2_dev); if(cam->buffers) { DBG("Wakeup waiting processes\n"); @@ -897,6 +896,8 @@ static void cpia2_usb_disconnect(struct DBG("Releasing interface\n"); usb_driver_release_interface(&cpia2_driver, intf); + v4l2_device_put(&cam->v4l2_dev); + LOG("CPiA2 camera disconnected.\n"); }