From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753999AbcJDN17 (ORCPT ); Tue, 4 Oct 2016 09:27:59 -0400 Received: from twin.jikos.cz ([89.185.236.188]:55452 "EHLO twin.jikos.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751754AbcJDN15 (ORCPT ); Tue, 4 Oct 2016 09:27:57 -0400 Date: Tue, 4 Oct 2016 15:26:28 +0200 (CEST) From: Jiri Kosina X-X-Sender: jikos@twin.jikos.cz To: =?ISO-8859-15?Q?J=F6rg_Otte?= cc: Linux Kernel Mailing List , Andy Lutomirski , Linus Torvalds , Ingo Molnar , Michael Krufky , Mauro Carvalho Chehab , Patrick Boettcher , linux-media@vger.kernel.org Subject: Re: Problem with VMAP_STACK=y In-Reply-To: Message-ID: References: User-Agent: Alpine 2.00 (LRH 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 4 Oct 2016, Jörg Otte wrote: > With kernel 4.8.0-01558-g21f54dd I get thousands of > "dvb-usb: bulk message failed: -11 (1/0)" > messages in the logs and the DVB adapter is not working. > > It tourned out the new config option VMAP_STACK=y (which is the default) > is the culprit. > No problems for me with VMAP_STACK=n. I'd guess that this is EAGAIN coming from usb_hcd_map_urb_for_dma() as the DVB driver is trying to perform on-stack DMA. Not really knowing which driver exactly you're using, I quickly skimmed through DVB sources, and it turns out this indeed seems to be rather common antipattern, and it should be fixed nevertheless. See cxusb_ctrl_msg() dibusb_power_ctrl() dibusb2_0_streaming_ctrl() dibusb2_0_power_ctrl() digitv_ctrl_msg() dtt200u_fe_init() dtt200u_fe_set_frontend() dtt200u_power_ctrl() dtt200u_streaming_ctrl() dtt200u_pid_filter() Adding relevant CCs. -- Jiri Kosina SUSE Labs