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=-7.0 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 8E1E7C43387 for ; Mon, 7 Jan 2019 08:49:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 62C272087F for ; Mon, 7 Jan 2019 08:49:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726609AbfAGItZ (ORCPT ); Mon, 7 Jan 2019 03:49:25 -0500 Received: from mail5.windriver.com ([192.103.53.11]:51090 "EHLO mail5.wrs.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726496AbfAGItZ (ORCPT ); Mon, 7 Jan 2019 03:49:25 -0500 Received: from ALA-HCA.corp.ad.wrs.com (ala-hca.corp.ad.wrs.com [147.11.189.40]) by mail5.wrs.com (8.15.2/8.15.2) with ESMTPS id x078l5FZ024630 (version=TLSv1 cipher=AES128-SHA bits=128 verify=FAIL); Mon, 7 Jan 2019 00:47:15 -0800 Received: from [128.224.162.180] (128.224.162.180) by ALA-HCA.corp.ad.wrs.com (147.11.189.50) with Microsoft SMTP Server (TLS) id 14.3.408.0; Mon, 7 Jan 2019 00:46:55 -0800 Subject: Re: [PATCH v2] kernel/dma: Fix panic caused by passing swiotlb to command line To: , , , , , , References: <1543832571-121638-1-git-send-email-zhe.he@windriver.com> From: He Zhe Message-ID: Date: Mon, 7 Jan 2019 16:46:51 +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: <1543832571-121638-1-git-send-email-zhe.he@windriver.com> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Content-Language: en-US X-Originating-IP: [128.224.162.180] Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Kindly ping. Zhe On 12/3/18 6:22 PM, 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 and sets it for 4MB by default. > > 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 > > Signed-off-by: He Zhe > --- > v2: Set swiotlb for 4MB by default > > kernel/dma/swiotlb.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c > index 045930e..0e18cd4 100644 > --- a/kernel/dma/swiotlb.c > +++ b/kernel/dma/swiotlb.c > @@ -58,6 +58,9 @@ > */ > #define IO_TLB_MIN_SLABS ((1<<20) >> IO_TLB_SHIFT) > > +#define IO_TLB_DEFAULT_MB 4 > +#define IO_TLB_DEFAULT_SLABS ((IO_TLB_DEFAULT_MB<<20) >> IO_TLB_SHIFT) > + > enum swiotlb_force swiotlb_force; > > /* > @@ -103,6 +106,14 @@ static int late_alloc; > static int __init > setup_io_tlb_npages(char *str) > { > + if (!str) { > + pr_err("No value provided for swiotlb, " > + "set it to %d slabs for %dMB by default.\n", > + IO_TLB_DEFAULT_SLABS, IO_TLB_DEFAULT_MB); > + io_tlb_nslabs = IO_TLB_DEFAULT_SLABS; > + return 0; > + } > + > if (isdigit(*str)) { > io_tlb_nslabs = simple_strtoul(str, &str, 0); > /* avoid tail segment of size < IO_TLB_SEGSIZE */