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 E7C2DC10F0C for ; Thu, 4 Apr 2019 11:18:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BCDA620855 for ; Thu, 4 Apr 2019 11:18:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729712AbfDDLSB (ORCPT ); Thu, 4 Apr 2019 07:18:01 -0400 Received: from szxga06-in.huawei.com ([45.249.212.32]:51904 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729686AbfDDLR4 (ORCPT ); Thu, 4 Apr 2019 07:17:56 -0400 Received: from DGGEMS407-HUB.china.huawei.com (unknown [172.30.72.59]) by Forcepoint Email with ESMTP id BC451FC1B5B43334F48F; Thu, 4 Apr 2019 19:17:54 +0800 (CST) Received: from [127.0.0.1] (10.202.227.238) by DGGEMS407-HUB.china.huawei.com (10.3.19.207) with Microsoft SMTP Server id 14.3.408.0; Thu, 4 Apr 2019 19:17:43 +0800 Subject: Re: [PATCH] driver core: Postpone DMA tear-down until after devres release for probe failure To: Greg KH , 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> CC: , , , , , , , , From: John Garry Message-ID: Date: Thu, 4 Apr 2019 12:17:37 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.3.0 MIME-Version: 1.0 In-Reply-To: <3e1f3e2e-a1d3-ecaf-0931-44b4c10faffe@huawei.com> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.202.227.238] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. So 376991db4b64 required manual backporting to stable, and this patch would require the same: https://www.spinics.net/lists/stable/msg289685.html Robin, any further comment? Thanks, John >> thanks, >> >> greg k-h >> >> . >> >