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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 83996C433EF for ; Fri, 17 Jun 2022 12:51:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236407AbiFQMvY (ORCPT ); Fri, 17 Jun 2022 08:51:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40430 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232477AbiFQMvY (ORCPT ); Fri, 17 Jun 2022 08:51:24 -0400 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 80DC137A84; Fri, 17 Jun 2022 05:51:23 -0700 (PDT) Received: from pendragon.ideasonboard.com (62-78-145-57.bb.dnainternet.fi [62.78.145.57]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 192342A5; Fri, 17 Jun 2022 14:51:21 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1655470281; bh=6044Ae7YHS8XgtS8M1tFoHpK4NiU+wwOXC2x7BQ7Z78=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=COaincPjdXKl1B+/5mkNRMn6kFQ0raht3IJWuZ1+RxMFAYBQ1Fpk+blOKhy2VPFIP wcMEOHgGxalCoUiO33fS7JrK9xfBVY2VQ2CEnYmVR+kF992v+Me3UWHrEg4f8KQpii DMLmJ7laRYi2GnE74q7+Cz+j87s8nCqnvFczrMCE= Date: Fri, 17 Jun 2022 15:51:08 +0300 From: Laurent Pinchart To: Dan Vacura Cc: linux-usb@vger.kernel.org, stable@vger.kernel.org, Felipe Balbi , Greg Kroah-Hartman , Paul Elder , Michael Grzeschik , linux-kernel@vger.kernel.org Subject: Re: [PATCH] usb: gadget: uvc: fix list double add in uvcg_video_pump Message-ID: References: <20220616030915.149238-1-w36195@motorola.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20220616030915.149238-1-w36195@motorola.com> Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org Hi Dan, Thank you for the patch. On Wed, Jun 15, 2022 at 10:09:15PM -0500, Dan Vacura wrote: > A panic can occur if the endpoint becomes disabled and the > uvcg_video_pump adds the request back to the req_free list after it has > already been queued to the endpoint. The endpoint complete will add the > request back to the req_free list. Invalidate the local request handle > once it's been queued. Good catch ! > <6>[ 246.796704][T13726] configfs-gadget gadget: uvc: uvc_function_set_alt(1, 0) > <3>[ 246.797078][ T26] list_add double add: new=ffffff878bee5c40, prev=ffffff878bee5c40, next=ffffff878b0f0a90. > <6>[ 246.797213][ T26] ------------[ cut here ]------------ > <2>[ 246.797224][ T26] kernel BUG at lib/list_debug.c:31! > <6>[ 246.807073][ T26] Call trace: > <6>[ 246.807180][ T26] uvcg_video_pump+0x364/0x38c > <6>[ 246.807366][ T26] process_one_work+0x2a4/0x544 > <6>[ 246.807394][ T26] worker_thread+0x350/0x784 > <6>[ 246.807442][ T26] kthread+0x2ac/0x320 > > Fixes: f9897ec0f6d3 ("usb: gadget: uvc: only pump video data if necessary") > Cc: stable@vger.kernel.org > Signed-off-by: Dan Vacura > --- > drivers/usb/gadget/function/uvc_video.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/usb/gadget/function/uvc_video.c b/drivers/usb/gadget/function/uvc_video.c > index 93f42c7f800d..59e2f51b53a5 100644 > --- a/drivers/usb/gadget/function/uvc_video.c > +++ b/drivers/usb/gadget/function/uvc_video.c > @@ -427,6 +427,9 @@ static void uvcg_video_pump(struct work_struct *work) > if (ret < 0) { > uvcg_queue_cancel(queue, 0); > break; > + } else { > + /* Endpoint now owns the request */ > + req = NULL; > } > video->req_int_count++; I'd write it as if (ret < 0) { uvcg_queue_cancel(queue, 0); break; } /* Endpoint now owns the request. */ req = NULL; video->req_int_count++; Apart from that, Reviewed-by: Laurent Pinchart > } -- Regards, Laurent Pinchart