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: [1/5] USB: serial: fix unthrottle races From: Oliver Neukum Message-Id: <1556531458.20085.8.camel@suse.com> Date: Mon, 29 Apr 2019 11:50:58 +0200 To: Johan Hovold , Greg Kroah-Hartman , Alan Stern Cc: linux-usb@vger.kernel.org List-ID: T24gRG8sIDIwMTktMDQtMjUgYXQgMTg6MDUgKzAyMDAsIEpvaGFuIEhvdm9sZCB3cm90ZToKPiBA QCAtNDg0LDYgKzUwMywxMiBAQCB2b2lkIHVzYl9zZXJpYWxfZ2VuZXJpY191bnRocm90dGxlKHN0 cnVjdCB0dHlfc3RydWN0ICp0dHkpCj4gICAgICAgICBwb3J0LT50aHJvdHRsZWQgPSBwb3J0LT50 aHJvdHRsZV9yZXEgPSAwOwo+ICAgICAgICAgc3Bpbl91bmxvY2tfaXJxKCZwb3J0LT5sb2NrKTsK PiAgCj4gKyAgICAgICAvKgo+ICsgICAgICAgICogTWF0Y2hlcyB0aGUgc21wX21iX19hZnRlcl9h dG9taWMoKSBpbgo+ICsgICAgICAgICogdXNiX3NlcmlhbF9nZW5lcmljX3JlYWRfYnVsa19jYWxs YmFjaygpLgo+ICsgICAgICAgICovCj4gKyAgICAgICBzbXBfbWIoKTsKPiArCj4gICAgICAgICBp ZiAod2FzX3Rocm90dGxlZCkKPiAgICAgICAgICAgICAgICAgdXNiX3NlcmlhbF9nZW5lcmljX3N1 Ym1pdF9yZWFkX3VyYnMocG9ydCwgR0ZQX0tFUk5FTCk7CgoKRG9lc24ndCB0aGUgc3Bpbl91bmxv Y2tfaXJxKCkgaW1wbHkgc21wX21iKCk/Ck90aGVyd2lzZSBpdCBsb29rcyBjb3JyZWN0IHRvIG1l LgoKCVJlZ2FyZHMKCQlPbGl2ZXIK 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=-0.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 C3922C43219 for ; Mon, 29 Apr 2019 09:51:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9EFA52087B for ; Mon, 29 Apr 2019 09:51:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727616AbfD2Jva (ORCPT ); Mon, 29 Apr 2019 05:51:30 -0400 Received: from mx2.suse.de ([195.135.220.15]:57134 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727514AbfD2Jv3 (ORCPT ); Mon, 29 Apr 2019 05:51:29 -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 17967ADE6; Mon, 29 Apr 2019 09:51:10 +0000 (UTC) Message-ID: <1556531458.20085.8.camel@suse.com> Subject: Re: [PATCH 1/5] USB: serial: fix unthrottle races From: Oliver Neukum To: Johan Hovold , Greg Kroah-Hartman , Alan Stern Cc: linux-usb@vger.kernel.org Date: Mon, 29 Apr 2019 11:50:58 +0200 In-Reply-To: <20190425160540.10036-2-johan@kernel.org> References: <20190425160540.10036-1-johan@kernel.org> <20190425160540.10036-2-johan@kernel.org> 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 Message-ID: <20190429095058.Zs4Oy8jj_khxXq8s_0sLcCTjQDGL6SFFx0a2M-TdmsQ@z> On Do, 2019-04-25 at 18:05 +0200, Johan Hovold wrote: > @@ -484,6 +503,12 @@ void usb_serial_generic_unthrottle(struct tty_struct *tty) > port->throttled = port->throttle_req = 0; > spin_unlock_irq(&port->lock); > > + /* > + * Matches the smp_mb__after_atomic() in > + * usb_serial_generic_read_bulk_callback(). > + */ > + smp_mb(); > + > if (was_throttled) > usb_serial_generic_submit_read_urbs(port, GFP_KERNEL); Doesn't the spin_unlock_irq() imply smp_mb()? Otherwise it looks correct to me. Regards Oliver