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 62F95C3F2CD for ; Wed, 4 Mar 2020 14:13:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 40CC62072A for ; Wed, 4 Mar 2020 14:13:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729481AbgCDONK (ORCPT ); Wed, 4 Mar 2020 09:13:10 -0500 Received: from mx2.suse.de ([195.135.220.15]:53852 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729286AbgCDONK (ORCPT ); Wed, 4 Mar 2020 09:13:10 -0500 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 D1DB2B2AC; Wed, 4 Mar 2020 14:13:08 +0000 (UTC) Message-ID: <1583331173.12738.26.camel@suse.com> Subject: Re: USB transaction errors causing RCU stalls and kernel panics From: Oliver Neukum To: Mathias Nyman , Jonas Karlsson , Greg KH Cc: "linux-usb@vger.kernel.org" Date: Wed, 04 Mar 2020 15:12:53 +0100 In-Reply-To: <6909d182-6cc5-c07f-ed79-02c741aec60b@linux.intel.com> References: <20200303163945.GB652754@kroah.com> <6909d182-6cc5-c07f-ed79-02c741aec60b@linux.intel.com> 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 04.03.2020, 14:11 +0200 schrieb Mathias Nyman: > On 3.3.2020 22.08, Jonas Karlsson wrote: > > I recently got a report about a bit similar issue on a 4.4 stable kernel, so this > might not be xhci-cdns specific. > > That case involved autosuspend of the cdc-acm, and there was only a short burst of > transaction erros and resubmitted URBs even if the device was supposed to be suspended. > It looks like cdc_acm autosuspended even if it had URBs pending. That must not happen. Do you have details? > I'm guessing that in that case the transfer ring restarted even if link was already "suspeded", > causing transaction errors. Ring could be restarted if URBs were resubmitted > by the class driver when usb core suspends all interfaces, flushing all pending URBs which > calls the URB completion handler. How should a class driver do that? It gets -EPROTO and that's it, Regards Oliver