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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 089F1C43381 for ; Mon, 25 Mar 2019 10:47:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D03692085A for ; Mon, 25 Mar 2019 10:47:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730863AbfCYKrB (ORCPT ); Mon, 25 Mar 2019 06:47:01 -0400 Received: from mx2.suse.de ([195.135.220.15]:34706 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729727AbfCYKrB (ORCPT ); Mon, 25 Mar 2019 06:47:01 -0400 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 9605AAF3F; Mon, 25 Mar 2019 10:46:59 +0000 (UTC) Message-ID: <1553510086.2668.2.camel@suse.com> Subject: Re: [PATCH] usb: uas: fix usb subsystem hang after power off hub port From: Oliver Neukum To: Kento.A.Kobayashi@sony.com, gregkh@linuxfoundation.org, stern@rowland.harvard.edu Cc: usb-storage@lists.one-eyed-alien.net, Jacky.Cao@sony.com, linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org, linux-usb@vger.kernel.org Date: Mon, 25 Mar 2019 11:34:46 +0100 In-Reply-To: References: <1552063928.29776.2.camel@suse.com> <1552405047.21557.7.camel@suse.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.26.6 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mo, 2019-03-25 at 10:21 +0000, Kento.A.Kobayashi@sony.com wrote: > Hi, > > > > > And the return value(-ENODEV) will be returned to error handler. > > > > uas_eh_device_reset_handler->usb_reset_device -> usb_reset_and_verify_device (return -ENODEV) Then I wrote that commit message that we think even if we ignore "ENODEV" in post reset to avoid hang issue but the error will also be reported to error handler. > > > > #If ignore an error and the error will not be reported then it is not good. > > > > > > Well, what do we do now? Are you saying that the state model SCSI is using is wrong? > > No, it is not wrong. > > But I think we may want to prevend hang by sleep peocess with continuing to take a lock at blk_execute_rq() from >usb_unbind_and_rebind_marded_interfaces(). > > Could you please you can apply this patch for mainline or not? > If not, could you please tell me why you can't allow to apply this patch? Sorry, I thought this was clear. Your patch is making the assumption that the reset is triggered by the SCSI layer. You cannot make that assumption, as there is an ioctl for resetting a USB device. In case we are getting an error during the reset (our endpoints vanish), the device driver must report that to the USB layer, so the driver will always be disconnected. We cannot drop errors. Regards Oliver From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: base64 Subject: usb: uas: fix usb subsystem hang after power off hub port From: Oliver Neukum Message-Id: <1553510086.2668.2.camel@suse.com> Date: Mon, 25 Mar 2019 11:34:46 +0100 To: Kento.A.Kobayashi@sony.com, gregkh@linuxfoundation.org, stern@rowland.harvard.edu Cc: usb-storage@lists.one-eyed-alien.net, Jacky.Cao@sony.com, linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org, linux-usb@vger.kernel.org List-ID: T24gTW8sIDIwMTktMDMtMjUgYXQgMTA6MjEgKzAwMDAsIEtlbnRvLkEuS29iYXlhc2hpQHNvbnku Y29tIHdyb3RlOgo+IEhpLAo+IAo+ID4gPiA+IEFuZCB0aGUgcmV0dXJuIHZhbHVlKC1FTk9ERVYp IHdpbGwgYmUgcmV0dXJuZWQgdG8gZXJyb3IgaGFuZGxlci4KPiA+ID4gPiB1YXNfZWhfZGV2aWNl X3Jlc2V0X2hhbmRsZXItPnVzYl9yZXNldF9kZXZpY2UgLT4gdXNiX3Jlc2V0X2FuZF92ZXJpZnlf ZGV2aWNlIChyZXR1cm4gLUVOT0RFVikgVGhlbiBJIHdyb3RlIHRoYXQgY29tbWl0IG1lc3NhZ2Ug dGhhdCB3ZSB0aGluayBldmVuIGlmIHdlIGlnbm9yZSAiRU5PREVWIiBpbiBwb3N0IHJlc2V0IHRv IGF2b2lkIGhhbmcgaXNzdWUgYnV0IHRoZSBlcnJvciB3aWxsIGFsc28gYmUgcmVwb3J0ZWQgdG8g ZXJyb3IgaGFuZGxlci4KPiA+ID4gPiAjSWYgaWdub3JlIGFuIGVycm9yIGFuZCB0aGUgZXJyb3Ig d2lsbCBub3QgYmUgcmVwb3J0ZWQgdGhlbiBpdCBpcyBub3QgZ29vZC4KPiA+ID4gCj4gPiA+IFdl bGwsIHdoYXQgZG8gd2UgZG8gbm93PyBBcmUgeW91IHNheWluZyB0aGF0IHRoZSBzdGF0ZSBtb2Rl bCBTQ1NJIGlzIHVzaW5nIGlzIHdyb25nPwo+ID4gTm8sIGl0IGlzIG5vdCB3cm9uZy4KPiA+IEJ1 dCBJIHRoaW5rIHdlIG1heSB3YW50IHRvIHByZXZlbmQgaGFuZyBieSBzbGVlcCBwZW9jZXNzIHdp dGggY29udGludWluZyB0byB0YWtlIGEgbG9jayBhdCBibGtfZXhlY3V0ZV9ycSgpIGZyb20gPnVz Yl91bmJpbmRfYW5kX3JlYmluZF9tYXJkZWRfaW50ZXJmYWNlcygpLgo+IAo+IENvdWxkIHlvdSBw bGVhc2UgeW91IGNhbiBhcHBseSB0aGlzIHBhdGNoIGZvciBtYWlubGluZSBvciBub3Q/Cj4gSWYg bm90LCBjb3VsZCB5b3UgcGxlYXNlIHRlbGwgbWUgd2h5IHlvdSBjYW4ndCBhbGxvdyB0byBhcHBs eSB0aGlzIHBhdGNoPwoKU29ycnksCgpJIHRob3VnaHQgdGhpcyB3YXMgY2xlYXIuIFlvdXIgcGF0 Y2ggaXMgbWFraW5nIHRoZSBhc3N1bXB0aW9uIHRoYXQKdGhlIHJlc2V0IGlzIHRyaWdnZXJlZCBi eSB0aGUgU0NTSSBsYXllci4gWW91IGNhbm5vdCBtYWtlIHRoYXQKYXNzdW1wdGlvbiwgYXMgdGhl cmUgaXMgYW4gaW9jdGwgZm9yIHJlc2V0dGluZyBhIFVTQiBkZXZpY2UuCkluIGNhc2Ugd2UgYXJl IGdldHRpbmcgYW4gZXJyb3IgZHVyaW5nIHRoZSByZXNldCAob3VyIGVuZHBvaW50cwp2YW5pc2gp LCB0aGUgZGV2aWNlIGRyaXZlciBtdXN0IHJlcG9ydCB0aGF0IHRvIHRoZSBVU0IgbGF5ZXIsCnNv IHRoZSBkcml2ZXIgd2lsbCBhbHdheXMgYmUgZGlzY29ubmVjdGVkLgpXZSBjYW5ub3QgZHJvcCBl cnJvcnMuCgoJUmVnYXJkcwoJCU9saXZlcgo=