Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932258AbcJEPxf (ORCPT ); Wed, 5 Oct 2016 11:53:35 -0400 Received: from mail-vk0-f54.google.com ([209.85.213.54]:33278 "EHLO mail-vk0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932227AbcJEPxd (ORCPT ); Wed, 5 Oct 2016 11:53:33 -0400 MIME-Version: 1.0 In-Reply-To: References: <20161005093417.6e82bd97@vdr> <20161005060450.1b0f2152@vento.lan> From: Andy Lutomirski Date: Wed, 5 Oct 2016 08:53:11 -0700 Message-ID: Subject: Re: Problem with VMAP_STACK=y To: =?UTF-8?Q?J=C3=B6rg_Otte?= Cc: Mauro Carvalho Chehab , Jiri Kosina , Patrick Boettcher , Linux Kernel Mailing List , Andy Lutomirski , Michael Krufky , Mauro Carvalho Chehab , Linux Media Mailing List Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by mail.home.local id u95FrhvR013537 Content-Length: 1730 Lines: 49 On Wed, Oct 5, 2016 at 8:21 AM, Jörg Otte wrote: > 2016-10-05 11:04 GMT+02:00 Mauro Carvalho Chehab : >> Em Wed, 5 Oct 2016 09:50:42 +0200 (CEST) >> Jiri Kosina escreveu: >> >>> On Wed, 5 Oct 2016, Patrick Boettcher wrote: >>> >>> > > > Thanks for the quick response. >>> > > > Drivers are: >>> > > > dvb_core, dvb_usb, dbv_usb_cynergyT2 >>> > > >>> > > This dbv_usb_cynergyT2 is not from Linus' tree, is it? I don't seem >>> > > to be able to find it, and the only google hit I am getting is your >>> > > very mail to LKML :) >>> > >>> > It's a typo, it should say dvb_usb_cinergyT2. >>> >>> Ah, thanks. Same issues there in >>> >>> cinergyt2_frontend_attach() >>> cinergyt2_rc_query() >>> >>> I think this would require more in-depth review of all the media drivers >>> and having all this fixed for 4.9. It should be pretty straightforward; >>> all the instances I've seen so far should be just straightforward >>> conversion to kmalloc() + kfree(), as the buffer is not being embedded in >>> any structure etc. >> >> What we're doing on most cases is to put a buffer (usually with 80 >> chars for USB drivers) inside the "state" struct (on DVB drivers), >> in order to avoid doing kmalloc/kfree all the times. One such patch is >> changeset c4a98793a63c4. >> >> I'm enclosing a non-tested patch fixing it for the cinergyT2-core.c >> driver. >> >> Thanks, >> Mauro >> >> [PATCH] cinergyT2-core: don't do DMA on stack >> > > Tried the cinergyT2 patch. No success. When I select a TV channel > just nothing happens. There are no error messages. Could you try compiling with CONFIG_DEBUG_VIRTUAL=y and seeing if you get a nice error message? --Andy