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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 8DCCDC433DF for ; Tue, 9 Jun 2020 05:43:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6585620774 for ; Tue, 9 Jun 2020 05:43:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727055AbgFIFnM (ORCPT ); Tue, 9 Jun 2020 01:43:12 -0400 Received: from verein.lst.de ([213.95.11.211]:40741 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725770AbgFIFnL (ORCPT ); Tue, 9 Jun 2020 01:43:11 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id 28BA868AFE; Tue, 9 Jun 2020 07:43:07 +0200 (CEST) Date: Tue, 9 Jun 2020 07:43:06 +0200 From: Christoph Hellwig To: David Rientjes Cc: "Alex Xu (Hello71)" , Christoph Hellwig , alsa-devel@alsa-project.org, bp@alien8.de, hch@infradead.org, hpa@zytor.com, linux-kernel@vger.kernel.org, mingo@redhat.com, Pavel Machek , perex@perex.cz, tglx@linutronix.de, tiwai@suse.com, x86@kernel.org Subject: Re: next-0519 on thinkpad x60: sound related? window manager crash Message-ID: <20200609054306.GA9606@lst.de> References: <20200520111136.GA3802@amd> <1591545088.74ii116nf2.none@localhost> <20200608061950.GA17476@lst.de> <1591624340.z01ejtod28.none@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 08, 2020 at 07:31:47PM -0700, David Rientjes wrote: > On Mon, 8 Jun 2020, Alex Xu (Hello71) wrote: > > > Excerpts from Christoph Hellwig's message of June 8, 2020 2:19 am: > > > Can you do a listing using gdb where this happens? > > > > > > gdb vmlinux > > > > > > l *(snd_pcm_hw_params+0x3f3) > > > > > > ? > > > > > > > (gdb) l *(snd_pcm_hw_params+0x3f3) > > 0xffffffff817efc85 is in snd_pcm_hw_params (.../linux/sound/core/pcm_native.c:749). > > 744 while (runtime->boundary * 2 <= LONG_MAX - runtime->buffer_size) > > 745 runtime->boundary *= 2; > > 746 > > 747 /* clear the buffer for avoiding possible kernel info leaks */ > > 748 if (runtime->dma_area && !substream->ops->copy_user) > > 749 memset(runtime->dma_area, 0, runtime->dma_bytes); > > 750 > > 751 snd_pcm_timer_resolution_change(substream); > > 752 snd_pcm_set_state(substream, SNDRV_PCM_STATE_SETUP); > > 753 > > > > Working theory is that CONFIG_DMA_NONCOHERENT_MMAP getting set is causing > the error_code in the page fault path. Debugging with Alex off-thread we > found that dma_{alloc,free}_from_pool() are not getting called from the > new code in dma_direct_{alloc,free}_pages() and he has not enabled > mem_encrypt. While DMA_COHERENT_POOL absolutely should not select DMA_NONCOHERENT_MMAP (and you should send your patch either way), I don't think it is going to make a difference here, as DMA_NONCOHERENT_MMAP just means we allows mmaps even for non-coherent devices, and we do not support non-coherent devices on x86. >From the disassembly it seems like a vmalloc allocation is NULL, which seems really weird as this patch shouldn't make a difference for them, and I also only see a single places that allocates the field, and that checks for an allocation failure. But the sound code is a little hard to unwind sometimes.