From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754028Ab1CUT1y (ORCPT ); Mon, 21 Mar 2011 15:27:54 -0400 Received: from proofpoint-cluster.metrocast.net ([65.175.128.136]:59407 "EHLO proofpoint-cluster.metrocast.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752468Ab1CUT1w (ORCPT ); Mon, 21 Mar 2011 15:27:52 -0400 References: <1300732426-18958-1-git-send-email-florian@mickler.org> User-Agent: K-9 Mail for Android In-Reply-To: <1300732426-18958-1-git-send-email-florian@mickler.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Subject: Re: [PATCH 0/6] get rid of on-stack dma buffers From: Andy Walls Date: Mon, 21 Mar 2011 15:26:43 -0400 To: Florian Mickler , mchehab@infradead.org CC: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, js@linuxtv.org, tskd2@yahoo.co.jp, liplianin@me.by, g.marco@freenet.de, aet@rasterburn.org, pb@linuxtv.org, mkrufky@linuxtv.org, nick@nick-andrew.net, max@veneto.com, janne-dvb@grunau.be Message-ID: X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:5.2.15,1.0.148,0.0.0000 definitions=2011-03-21_06:2011-03-16,2011-03-21,1970-01-01 signatures=0 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 ipscore=0 suspectscore=2 phishscore=0 bulkscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx engine=5.0.0-1012030000 definitions=main-1103210117 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Florian Mickler wrote: >Hi all! > >These patches get rid of on-stack dma buffers for some of the dvb-usb >drivers. >I do not own the hardware, so these are only compile tested. I would >appreciate testing and review. >They were previously sent to the list, but some error on my side >prevented (some of?) them from beeing delivered to all parties (the >lists). > >These changes are motivated by >https://bugzilla.kernel.org/show_bug.cgi?id=15977 . > >The patches which got tested already were submitted to Mauro (and >lkml/linux-media) yesterday seperately. Those fix this same issue for >ec168, >ce6230, au6610 and lmedm04. > >A fix for vp702x has been submitted seperately for review on the list. >I have >similiar fixes like the vp702x-fix for dib0700 (overlooked some >on-stack >buffers in there in my original submission as well) and gp8psk, but I >am >holding them back 'till I got time to recheck those and getting some >feedback >on vp702x. > >Please review and test. > >Regards, >Flo > >Florian Mickler (6): > [media] a800: get rid of on-stack dma buffers > [media v2] vp7045: get rid of on-stack dma buffers > [media] friio: get rid of on-stack dma buffers > [media] dw2102: get rid of on-stack dma buffer > [media] m920x: get rid of on-stack dma buffers > [media] opera1: get rid of on-stack dma buffer > > drivers/media/dvb/dvb-usb/a800.c | 17 ++++++++++--- > drivers/media/dvb/dvb-usb/dw2102.c | 10 ++++++- > drivers/media/dvb/dvb-usb/friio.c | 23 ++++++++++++++--- > drivers/media/dvb/dvb-usb/m920x.c | 33 ++++++++++++++++-------- > drivers/media/dvb/dvb-usb/opera1.c | 31 +++++++++++++++-------- >drivers/media/dvb/dvb-usb/vp7045.c | 47 >++++++++++++++++++++++++++---------- > 6 files changed, 116 insertions(+), 45 deletions(-) > >-- >1.7.4.1 > >-- >To unsubscribe from this list: send the line "unsubscribe linux-media" >in >the body of a message to majordomo@vger.kernel.org >More majordomo info at http://vger.kernel.org/majordomo-info.html Florian, For all of these, what happens when the USB call times out and you kfree() the buffer? Can the USB DMA actually complete after this kfree(), possibly corrupting space that has been reallocated off the heap, since the kfree()? This is the scenario for which I assume allocating off the stack is bad. Do these changes simply make corruption less noticable since heap gets corrupted vs stack? Regards, Andy