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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 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 3D09BC432C0 for ; Thu, 28 Nov 2019 10:51:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1AF7821741 for ; Thu, 28 Nov 2019 10:51:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726569AbfK1KvG (ORCPT ); Thu, 28 Nov 2019 05:51:06 -0500 Received: from mx2.suse.de ([195.135.220.15]:38500 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726227AbfK1KvG (ORCPT ); Thu, 28 Nov 2019 05:51:06 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 0E73DAD78; Thu, 28 Nov 2019 10:51:03 +0000 (UTC) Message-ID: <1574938260.21204.5.camel@suse.com> Subject: Re: KASAN: use-after-free Read in si470x_int_in_callback (2) From: Oliver Neukum To: Alan Stern , syzbot Cc: andreyknvl@google.com, hverkuil@xs4all.nl, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-usb@vger.kernel.org, mchehab@kernel.org, syzkaller-bugs@googlegroups.com Date: Thu, 28 Nov 2019 11:51:00 +0100 In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.26.6 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org Am Mittwoch, den 27.11.2019, 13:07 -0500 schrieb Alan Stern: > Index: usb-devel/drivers/media/radio/si470x/radio-si470x-usb.c > =================================================================== > --- usb-devel.orig/drivers/media/radio/si470x/radio-si470x-usb.c > +++ usb-devel/drivers/media/radio/si470x/radio-si470x-usb.c > @@ -370,15 +370,14 @@ static void si470x_int_in_callback(struc > unsigned char tmpbuf[3]; > > if (urb->status) { > - if (urb->status == -ENOENT || > + if (!(urb->status == -ENOENT || > urb->status == -ECONNRESET || > - urb->status == -ESHUTDOWN) { > - return; > - } else { > + urb->status == -ESHUTDOWN)) > dev_warn(&radio->intf->dev, > - "non-zero urb status (%d)\n", urb->status); > - goto resubmit; /* Maybe we can recover. */ > - } > + "unrecognized urb status (%d)\n", > + urb->status); > + radio->int_in_running = 0; > + return; Hi, it is a bit awkward to complain here, as your patch tests as correct while mine didn't, but this is a race condition. You can't guarantee that urb->status != 0. The kill may happen while the completion handler is running for a successful transfer. I really appreciate your help, but I must understand what is going wrong here. You are stopping the resubmit, but how could the resubmit ever have not failed? Regards Oliver