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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,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 40FB3C10F27 for ; Mon, 9 Mar 2020 14:41:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0EA482067C for ; Mon, 9 Mar 2020 14:41:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726676AbgCIOlD convert rfc822-to-8bit (ORCPT ); Mon, 9 Mar 2020 10:41:03 -0400 Received: from unicorn.mansr.com ([81.2.72.234]:54000 "EHLO unicorn.mansr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726520AbgCIOlD (ORCPT ); Mon, 9 Mar 2020 10:41:03 -0400 Received: by unicorn.mansr.com (Postfix, from userid 51770) id 727D415F11; Mon, 9 Mar 2020 14:41:01 +0000 (GMT) From: =?iso-8859-1?Q?M=E5ns_Rullg=E5rd?= To: Bin Liu Cc: Greg Kroah-Hartman , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] usb: musb: fix crash with highmen PIO and usbmon References: <20200307130720.16652-1-mans@mansr.com> <20200309140106.GA31115@iaqt7> Date: Mon, 09 Mar 2020 14:41:01 +0000 In-Reply-To: <20200309140106.GA31115@iaqt7> (Bin Liu's message of "Mon, 9 Mar 2020 09:01:06 -0500") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org Bin Liu writes: > Hi Mans, > > On Sat, Mar 07, 2020 at 01:07:20PM +0000, Mans Rullgard wrote: >> When handling a PIO bulk transfer with highmem buffer, a temporary >> mapping is assigned to urb->transfer_buffer. After the transfer is >> complete, an invalid address is left behind in this pointer. This is >> not ordinarily a problem since nothing touches that buffer before the >> urb is released. However, when usbmon is active, usbmon_urb_complete() >> calls (indirectly) mon_bin_get_data() which does access the transfer >> buffer if it is set. To prevent an invalid memory access here, reset >> urb->tranfer_buffer to NULL when finished. >> >> Fixes: 8e8a55165469 ("usb: musb: host: Handle highmem in PIO mode") >> Signed-off-by: Mans Rullgard > > Thanks for fixing the bug. > >> --- >> drivers/usb/musb/musb_host.c | 8 ++++++-- >> 1 file changed, 6 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_host.c >> index 1c813c37462a..b67b40de1947 100644 >> --- a/drivers/usb/musb/musb_host.c >> +++ b/drivers/usb/musb/musb_host.c >> @@ -1459,8 +1459,10 @@ void musb_host_tx(struct musb *musb, u8 epnum) >> qh->segsize = length; >> >> if (qh->use_sg) { >> - if (offset + length >= urb->transfer_buffer_length) >> + if (offset + length >= urb->transfer_buffer_length) { >> qh->use_sg = false; >> + urb->transfer_buffer = NULL; >> + } > > In this tx case, can you directly pass qh->sg_miter.addr to > musb_write_fifo() so that urb->transfer_buffer is not touched at all? Yes, that seems to work. I'll prepare a new patch. -- Måns Rullgård