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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,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 5763FC2BC61 for ; Tue, 30 Oct 2018 11:06:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 18FE72075D for ; Tue, 30 Oct 2018 11:06:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 18FE72075D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=windriver.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727752AbeJ3T7v (ORCPT ); Tue, 30 Oct 2018 15:59:51 -0400 Received: from mail.windriver.com ([147.11.1.11]:33980 "EHLO mail.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727381AbeJ3T7v (ORCPT ); Tue, 30 Oct 2018 15:59:51 -0400 Received: from ALA-HCA.corp.ad.wrs.com ([147.11.189.40]) by mail.windriver.com (8.15.2/8.15.1) with ESMTPS id w9UB6I9x011952 (version=TLSv1 cipher=AES128-SHA bits=128 verify=FAIL); Tue, 30 Oct 2018 04:06:19 -0700 (PDT) Received: from [128.224.162.216] (128.224.162.216) by ALA-HCA.corp.ad.wrs.com (147.11.189.50) with Microsoft SMTP Server (TLS) id 14.3.408.0; Tue, 30 Oct 2018 04:06:18 -0700 Subject: Re: [PATCH] kernel/dma: Fix panic caused by passing swiotlb to command line To: Konrad Rzeszutek Wilk CC: , , , , , References: <1537154831-447363-1-git-send-email-zhe.he@windriver.com> <20181022192921.GA20677@dhcp-10-175-29-12.vpn.oracle.com> <87ee40fa-7a01-4d4c-7fa3-81aafc93e14f@windriver.com> From: He Zhe Message-ID: <5fa82cb9-bd32-8a3f-ddca-053f544e2883@windriver.com> Date: Tue, 30 Oct 2018 19:06:10 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <87ee40fa-7a01-4d4c-7fa3-81aafc93e14f@windriver.com> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Content-Language: en-US X-Originating-IP: [128.224.162.216] Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2018/10/23 19:14, He Zhe wrote: > > On 2018/10/23 03:29, Konrad Rzeszutek Wilk wrote: >> On Sat, Sep 22, 2018 at 08:56:58PM +0800, He Zhe wrote: >>> May I have your input? >> Alternatively would it make more sense for it to assume some default >> value? > Maybe, but the original code has no default value and I have no idea > what default value is proper here. Can anyone give some suggestions? Though I'd prefer to do nothing when no option is provided. Thanks, Zhe > > Zhe > >>> Thanks, >>> Zhe >>> >>> On 2018年09月17日 11:27, zhe.he@windriver.com wrote: >>>> From: He Zhe >>>> >>>> setup_io_tlb_npages does not check input argument before passing it >>>> to isdigit. The argument would be a NULL pointer if "swiotlb", without >>>> its value, is set in command line and thus causes the following panic. >>>> >>>> PANIC: early exception 0xe3 IP 10:ffffffffbb9b8e9f error 0 cr2 0x0 >>>> [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.19.0-rc3-yocto-standard+ #9 >>>> [ 0.000000] RIP: 0010:setup_io_tlb_npages+0xf/0x95 >>>> ... >>>> [ 0.000000] Call Trace: >>>> [ 0.000000] do_early_param+0x57/0x8e >>>> [ 0.000000] parse_args+0x208/0x320 >>>> [ 0.000000] ? rdinit_setup+0x30/0x30 >>>> [ 0.000000] parse_early_options+0x29/0x2d >>>> [ 0.000000] ? rdinit_setup+0x30/0x30 >>>> [ 0.000000] parse_early_param+0x36/0x4d >>>> [ 0.000000] setup_arch+0x336/0x99e >>>> [ 0.000000] start_kernel+0x6f/0x4e6 >>>> [ 0.000000] x86_64_start_reservations+0x24/0x26 >>>> [ 0.000000] x86_64_start_kernel+0x6f/0x72 >>>> [ 0.000000] secondary_startup_64+0xa4/0xb0 >>>> >>>> This patch adds a check to prevent the panic. >>>> >>>> Signed-off-by: He Zhe >>>> Cc: stable@vger.kernel.org >>>> Cc: konrad.wilk@oracle.com >>>> Cc: hch@lst.de >>>> Cc: m.szyprowski@samsung.com >>>> Cc: robin.murphy@arm.com >>>> --- >>>> kernel/dma/swiotlb.c | 5 +++++ >>>> 1 file changed, 5 insertions(+) >>>> >>>> diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c >>>> index 4f8a6db..46fc34e 100644 >>>> --- a/kernel/dma/swiotlb.c >>>> +++ b/kernel/dma/swiotlb.c >>>> @@ -109,6 +109,11 @@ static int late_alloc; >>>> static int __init >>>> setup_io_tlb_npages(char *str) >>>> { >>>> + if (!str) { >>>> + pr_err("Config string not provided\n"); >>>> + return -EINVAL; >>>> + } >>>> + >>>> if (isdigit(*str)) { >>>> io_tlb_nslabs = simple_strtoul(str, &str, 0); >>>> /* avoid tail segment of size < IO_TLB_SEGSIZE */ >>> _______________________________________________ >>> iommu mailing list >>> iommu@lists.linux-foundation.org >>> https://lists.linuxfoundation.org/mailman/listinfo/iommu >