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=-2.3 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 B2E20C10F27 for ; Wed, 11 Mar 2020 10:28:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 85879208E4 for ; Wed, 11 Mar 2020 10:28:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729019AbgCKK2r (ORCPT ); Wed, 11 Mar 2020 06:28:47 -0400 Received: from mx2.suse.de ([195.135.220.15]:40988 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726000AbgCKK2q (ORCPT ); Wed, 11 Mar 2020 06:28:46 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id D4095B1DD; Wed, 11 Mar 2020 10:28:44 +0000 (UTC) Message-ID: <1583922523.20566.4.camel@suse.com> Subject: Re: USB transaction errors causing RCU stalls and kernel panics From: Oliver Neukum To: Jonas Karlsson , Fabio Estevam Cc: Peter Chen , Mathias Nyman , Greg KH , "linux-usb@vger.kernel.org" , Alan Stern Date: Wed, 11 Mar 2020 11:28:43 +0100 In-Reply-To: References: <20200303163945.GB652754@kroah.com> <6909d182-6cc5-c07f-ed79-02c741aec60b@linux.intel.com> <1583331173.12738.26.camel@suse.com> <4fa64e92-64ce-07f3-ed8e-ea4e07d091bb@linux.intel.com> <699a49f2f69e494ea6558b99fad23cc4@actia.se> <20200310081452.GA14625@b29397-desktop> <1583838270.11582.11.camel@suse.com> <1583839306.11582.12.camel@suse.de> <325d5af5d4c44eafac94fc8e0e4d1a7d@actia.se> 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 11.03.2020, 06:25 +0000 schrieb Jonas Karlsson: > Hi Fabio, > > > Hi Jonas, > > > > On Tue, Mar 10, 2020 at 1:07 PM Jonas Karlsson > > wrote: > > > > > I have also _reverted_ this patch after recommendation from NXP to avoid > > > > RCU stall > > > crashes: > > > > > > commit 077506972ba23772b752e08b1ab7052cf5f04511 > > > Author: Paul E. McKenney > > > Date: Mon Jul 9 13:47:30 2018 -0700 > > > > > > rcu: Make need_resched() respond to urgent RCU-QS needs > > > > Could you please test without this revert? > > > > Thanks > > I removed the revert and it still works fine. Hi, it is good that we have something that works. It would be even better if we understood exactly how it works. In fact that these patches work and are needed may very well indicate that error handling on at least some XHCs does not work as expected. So a question and a request, if I may. Did you run the test with autosuspend disabled? If so could you retest with it enabled? Secondly could you run tests with commit 7c8f7af078a4eda73f347667d12584736e613062 Author: Oliver Neukum Date: Thu Mar 5 11:16:02 2020 +0100 cdc-acm: close race betrween suspend() and acm_softint not applied (respectively reverted) with and without autosuspend? Regards Oliver PS: When I submit upstream, may I add your 'Tested-by'?