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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 51F60C10F13 for ; Thu, 11 Apr 2019 11:01:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 199132184B for ; Thu, 11 Apr 2019 11:01:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726732AbfDKLBm (ORCPT ); Thu, 11 Apr 2019 07:01:42 -0400 Received: from foss.arm.com ([217.140.101.70]:40494 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726026AbfDKLBm (ORCPT ); Thu, 11 Apr 2019 07:01:42 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id A5CC8374; Thu, 11 Apr 2019 04:01:41 -0700 (PDT) Received: from [10.1.196.75] (e110467-lin.cambridge.arm.com [10.1.196.75]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D0BFD3F59C; Thu, 11 Apr 2019 04:01:39 -0700 (PDT) Subject: Re: [PATCH] driver core: Postpone DMA tear-down until after devres release for probe failure To: John Garry , Greg KH Cc: rafael@kernel.org, linuxarm@huawei.com, chenxiang66@hisilicon.com, geert@linux-m68k.org, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, linux-arm-kernel@lists.infradead.org, robh@kernel.org, hch@lst.de References: <1553767685-27077-1-git-send-email-john.garry@huawei.com> <703aca1f-9475-b50d-624a-5f1ceea2c3b2@huawei.com> <20190403081433.GA13222@kroah.com> <3e1f3e2e-a1d3-ecaf-0931-44b4c10faffe@huawei.com> From: Robin Murphy Message-ID: <198058c6-63c6-ac3c-62b7-438e5e3b3f0e@arm.com> Date: Thu, 11 Apr 2019 12:01:38 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/04/2019 09:50, John Garry wrote: > On 04/04/2019 12:17, John Garry wrote: >> On 03/04/2019 10:20, John Garry wrote: >>> On 03/04/2019 09:14, Greg KH wrote: >>>> On Wed, Apr 03, 2019 at 09:02:36AM +0100, John Garry wrote: >>>>> On 28/03/2019 10:08, John Garry wrote: >>>>>> In commit 376991db4b64 ("driver core: Postpone DMA tear-down until >>>>>> after >>>>>> devres release"), we changed the ordering of tearing down the device >>>>>> DMA >>>>>> ops and releasing all the device's resources; this was because the >>>>>> DMA ops >>>>>> should be maintained until we release the device's managed DMA >>>>>> memories. >>>>>> >>>>> >>>>> Hi all, >>>>> >>>>> A friendly reminder on this patch... I didn't see any update. >>>>> >>>>> I thought that it had some importance. >>>>> >>>>> Thanks, >>>>> John >>>>> >>>>>> However, we have seen another crash on an arm64 system when a >>>>>> device driver probe fails: >>>>>> >>>>>>   hisi_sas_v3_hw 0000:74:02.0: Adding to iommu group 2 >>>>>>   scsi host1: hisi_sas_v3_hw >>>>>>   BUG: Bad page state in process swapper/0  pfn:313f5 >>>>>>   page:ffff7e0000c4fd40 count:1 mapcount:0 >>>>>>   mapping:0000000000000000 index:0x0 >>>>>>   flags: 0xfffe00000001000(reserved) >>>>>>   raw: 0fffe00000001000 ffff7e0000c4fd48 ffff7e0000c4fd48 >>>>>> 0000000000000000 >>>>>>   raw: 0000000000000000 0000000000000000 00000001ffffffff >>>>>> 0000000000000000 >>>>>>   page dumped because: PAGE_FLAGS_CHECK_AT_FREE flag(s) set >>>>>>   bad because of flags: 0x1000(reserved) >>>>>>   Modules linked in: >>>>>>   CPU: 49 PID: 1 Comm: swapper/0 Not tainted >>>>>> 5.1.0-rc1-43081-g22d97fd-dirty #1433 >>>>>>   Hardware name: Huawei D06/D06, BIOS Hisilicon D06 UEFI >>>>>> RC0 - V1.12.01 01/29/2019 >>>>>>   Call trace: >>>>>>   dump_backtrace+0x0/0x118 >>>>>>   show_stack+0x14/0x1c >>>>>>   dump_stack+0xa4/0xc8 >>>>>>   bad_page+0xe4/0x13c >>>>>>   free_pages_check_bad+0x4c/0xc0 >>>>>>   __free_pages_ok+0x30c/0x340 >>>>>>   __free_pages+0x30/0x44 >>>>>>   __dma_direct_free_pages+0x30/0x38 >>>>>>   dma_direct_free+0x24/0x38 >>>>>>   dma_free_attrs+0x9c/0xd8 >>>>>>   dmam_release+0x20/0x28 >>>>>>   release_nodes+0x17c/0x220 >>>>>>   devres_release_all+0x34/0x54 >>>>>>   really_probe+0xc4/0x2c8 >>>>>>   driver_probe_device+0x58/0xfc >>>>>>   device_driver_attach+0x68/0x70 >>>>>>   __driver_attach+0x94/0xdc >>>>>>   bus_for_each_dev+0x5c/0xb4 >>>>>>   driver_attach+0x20/0x28 >>>>>>   bus_add_driver+0x14c/0x200 >>>>>>   driver_register+0x6c/0x124 >>>>>>   __pci_register_driver+0x48/0x50 >>>>>>   sas_v3_pci_driver_init+0x20/0x28 >>>>>>   do_one_initcall+0x40/0x25c >>>>>>   kernel_init_freeable+0x2b8/0x3c0 >>>>>>   kernel_init+0x10/0x100 >>>>>>   ret_from_fork+0x10/0x18 >>>>>>   Disabling lock debugging due to kernel taint >>>>>>   BUG: Bad page state in process swapper/0  pfn:313f6 >>>>>>   page:ffff7e0000c4fd80 count:1 mapcount:0 >>>>>> mapping:0000000000000000 index:0x0 >>>>>> [   89.322983] flags: 0xfffe00000001000(reserved) >>>>>>   raw: 0fffe00000001000 ffff7e0000c4fd88 ffff7e0000c4fd88 >>>>>> 0000000000000000 >>>>>>   raw: 0000000000000000 0000000000000000 00000001ffffffff >>>>>> 0000000000000000 >>>>>> >>>>>> The crash occurs for the same reason. >>>>>> >>>>>> In this case, on the really_probe() failure path, we are still >>>>>> clearing >>>>>> the DMA ops prior to releasing the device's managed memories. >>>>>> >>>>>> This patch fixes this issue by reordering the DMA ops teardown and >>>>>> the >>>>>> call to devres_release_all() on the failure path. >>>>>> >>>>>> Reported-by: Xiang Chen >>>>>> Tested-by: Xiang Chen >>>>>> Signed-off-by: John Garry >>>> >>>> So does this "fix" 376991db4b64?  If so, should this be added to the >>>> patch and also backported to the stable trees? >>> >>> Hi Greg, >>> >>> No, I don't think so. I'd say it supplements it. Here I'm trying to fix >>> up another path in which we tear down the DMA ops prior to releasing the >>> device's resources. >>> >>> I didn't add a fixes tag as 376991db4b64 didn't have one either. It will >>> need to be backported to stable, I figure the same as 376991db4b64. >> > > Hi Greg, > > I still think that we should consider merging this patch. Bah, sorry, I thought I'd replied to this thread already, but apparently not :( I don't have a particularly strong opinion, but at the moment I am leaning slightly towards this being a parallel fix for another part of 09515ef5ddad, rather than a specific fix of the other fix. Either way, you can have a: Reviewed-by: Robin Murphy Thanks, Robin.