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=-11.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 A55B5C433E6 for ; Fri, 26 Feb 2021 10:10:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1A9AA64F0E for ; Fri, 26 Feb 2021 10:10:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231259AbhBZKKC (ORCPT ); Fri, 26 Feb 2021 05:10:02 -0500 Received: from mail.kernel.org ([198.145.29.99]:33898 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231190AbhBZKH3 (ORCPT ); Fri, 26 Feb 2021 05:07:29 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id B3A7B64EC8; Fri, 26 Feb 2021 10:06:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1614334007; bh=uqGZSC/PHzNFwaCk1bS7DnKyCBFZztLa7wkzewkwZuI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=uhTKngNLyonN/UEwjQ1Wnopa3/5KEIfjVAhkRESfl9UX/YrXQB1h3sh+OZtC8p/bT QrCfTdbejg4DSk7KVFO8EctbfONLrY2lrckXsMjutWKklF7xMf9KBmGUq4t9yAO5mr XpyYltpYUC2YbZMe74e7FNpjqexF9j+2Eg/IKnZHrryBd/7vQiVEE+UeAsrxtyoO/T o3F9llUDrz8SBXJBUH/J0ZXS07g+q6Goj1HW/xipEiWkbvdvG8Xq9FqqWRDuubqjp4 89AiZPX50NPG2Q7OWEihcwknCi0LZkDtMO1YlVEqnOnvhNqlSFgAVJI8ZqPux6vIYa yHwAA2PxikwVw== Received: from johan by xi.lan with local (Exim 4.93.0.4) (envelope-from ) id 1lFa1b-0004vR-0i; Fri, 26 Feb 2021 11:07:07 +0100 Date: Fri, 26 Feb 2021 11:07:07 +0100 From: Johan Hovold To: Mauro Carvalho Chehab Cc: Manivannan Sadhasivam , gregkh@linuxfoundation.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, patong.mxl@gmail.com, linus.walleij@linaro.org, angelo.dureghello@timesys.com Subject: Re: [PATCH v5 1/3] usb: serial: Add MaxLinear/Exar USB to Serial driver Message-ID: References: <20201122170822.21715-1-mani@kernel.org> <20201122170822.21715-2-mani@kernel.org> <20210126154604.GC29751@thinkpad> <20210222161119.0bd70a2b@coco.lan> <20210225185820.0ae38ca6@coco.lan> <20210225190405.1f796da8@coco.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210225190405.1f796da8@coco.lan> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Feb 25, 2021 at 07:04:05PM +0100, Mauro Carvalho Chehab wrote: > Em Thu, 25 Feb 2021 18:58:20 +0100 > Mauro Carvalho Chehab escreveu: > > While testing the xr_serial (as currently merged), I opted to apply > > the patches on the top of vanilla Kernel 5.11 - as it sounds too risky > > to use linux-next so early on a new development cycle :-) > > > > There, I'm getting an OOPS: > > > > [ 30.261291] BUG: kernel NULL pointer dereference, address: 00000000000000a8 > > [ 30.261375] #PF: supervisor write access in kernel mode > > [ 30.261438] #PF: error_code(0x0002) - not-present page > > [ 30.261500] PGD 0 P4D 0 > > [ 30.261539] Oops: 0002 [#1] SMP PTI > > [ 30.261586] CPU: 2 PID: 686 Comm: kworker/2:3 Not tainted 5.11.0+ #14 > > [ 30.261666] Hardware name: /NUC5i7RYB, BIOS RYBDWi35.86A.0380.2019.0517.1530 05/17/2019 > > [ 30.261757] Workqueue: usb_hub_wq hub_event > > [ 30.261816] RIP: 0010:mutex_lock+0x1e/0x40 > > [ 30.262796] Call Trace: > > [ 30.262832] usb_serial_disconnect+0x33/0x140 > > [ 30.262897] usb_unbind_interface+0x8c/0x260 > > [ 30.262957] device_release_driver_internal+0x103/0x1d0 > > [ 30.263026] device_release_driver+0x12/0x20 > > [ 30.263083] bus_remove_device+0xe1/0x150 > > [ 30.263140] device_del+0x192/0x3f0 > > [ 30.263188] ? usb_remove_ep_devs+0x1f/0x30 > > [ 30.263244] usb_disable_device+0x95/0x1c0 > > [ 30.263300] usb_disconnect+0xc0/0x270 > > [ 30.263350] hub_event+0xa2e/0x1620 > > > > After adding this hack: > > > > > > --- a/drivers/usb/serial/usb-serial.c > > +++ b/drivers/usb/serial/usb-serial.c > > @@ -1081,6 +1081,11 @@ static void usb_serial_disconnect(struct usb_interface *interface) > > struct usb_serial_port *port; > > struct tty_struct *tty; > > > > + if (!serial) { > > + dev_err(dev, "%s: Serial pointer is NULL!!!\n", __func__); > > + return; > > + } > > + > > usb_serial_console_disconnect(serial); > > > > mutex_lock(&serial->disc_mutex); > > > > > > It works fine: > > > > [ 283.005625] xr_serial 2-1:1.1: xr_serial converter detected > > [ 283.005868] usb 2-1: xr_serial converter now attached to ttyUSB0 > > [ 283.007284] printk: console [ttyUSB0] enabled > > [ 284.444419] usb 2-1: USB disconnect, device number 5 > > [ 284.444520] xr_serial 2-1:1.0: usb_serial_disconnect: Serial pointer is NULL!!! > > [ 284.444894] printk: console [ttyUSB0] disabled > > [ 284.445091] xr_serial ttyUSB0: xr_serial converter now disconnected from ttyUSB0 > > [ 284.445141] xr_disconnect > > [ 284.445156] xr_serial 2-1:1.1: device disconnected > > > > I'm not sure if the bug is at xr_serial or if it is inside usb-serial.c. > > > > Any ideas? > > Answering myself, as those devices may have two different interfaces > (one for control and another one for data), I suspect that the > driver needs to manually call usb_set_intfdata() after detecting the > data interface. Thanks for reporting this. I'm afraid it's a bit more involved than that; we'd need to add support to USB-serial core for managing a sibling interface and either one being disconnected first. This has implications for suspend as well. I think we should just not claim the control interface for now since it not currently used by the driver. I'll send a fix. Johan