From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf1-f199.google.com (mail-pf1-f199.google.com [209.85.210.199]) by kanga.kvack.org (Postfix) with ESMTP id F04FF8E0001 for ; Sat, 22 Sep 2018 10:53:55 -0400 (EDT) Received: by mail-pf1-f199.google.com with SMTP id d1-v6so7884721pfo.16 for ; Sat, 22 Sep 2018 07:53:55 -0700 (PDT) Received: from mail.windriver.com (mail.windriver.com. [147.11.1.11]) by mx.google.com with ESMTPS id 14-v6si5871881pgm.488.2018.09.22.07.53.53 for (version=TLS1_1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Sat, 22 Sep 2018 07:53:54 -0700 (PDT) From: Subject: [PATCH v2 1/2] mm/page_alloc: Fix panic caused by passing debug_guardpage_minorder or kernelcore to command line Date: Sat, 22 Sep 2018 22:53:32 +0800 Message-ID: <1537628013-243902-1-git-send-email-zhe.he@windriver.com> MIME-Version: 1.0 Content-Type: text/plain Sender: owner-linux-mm@kvack.org List-ID: To: akpm@linux-foundation.org, mhocko@suse.com, vbabka@suse.cz, pasha.tatashin@oracle.com, mgorman@techsingularity.net, aaron.lu@intel.com, osalvador@suse.de, iamjoonsoo.kim@lge.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, zhe.he@windriver.com From: He Zhe debug_guardpage_minorder_setup and cmdline_parse_kernelcore do not check input argument before using it. The argument would be a NULL pointer if "debug_guardpage_minorder" or "kernelcore", without its value, is set in command line and thus causes the following panic. PANIC: early exception 0xe3 IP 10:ffffffffa08146f1 error 0 cr2 0x0 [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.19.0-rc4-yocto-standard+ #11 [ 0.000000] RIP: 0010:parse_option_str+0x11/0x90 ... [ 0.000000] Call Trace: [ 0.000000] cmdline_parse_kernelcore+0x19/0x41 [ 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/0x4ee [ 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 adds KBUILD_MODNAME to prints. Signed-off-by: He Zhe Cc: stable@vger.kernel.org Cc: akpm@linux-foundation.org Cc: mhocko@suse.com Cc: vbabka@suse.cz Cc: pasha.tatashin@oracle.com Cc: mgorman@techsingularity.net Cc: aaron.lu@intel.com Cc: osalvador@suse.de Cc: iamjoonsoo.kim@lge.com --- v2: Use more clear error info Split the addition of KBUILD_MODNAME out mm/page_alloc.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 89d2a2a..f34cae1 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -630,6 +630,12 @@ static int __init debug_guardpage_minorder_setup(char *buf) { unsigned long res; + if (!buf) { + pr_err("kernel option debug_guardpage_minorder requires an \ + argument\n"); + return -EINVAL; + } + if (kstrtoul(buf, 10, &res) < 0 || res > MAX_ORDER / 2) { pr_err("Bad debug_guardpage_minorder value\n"); return 0; @@ -6952,6 +6958,11 @@ static int __init cmdline_parse_core(char *p, unsigned long *core, */ static int __init cmdline_parse_kernelcore(char *p) { + if (!p) { + pr_err("kernel option kernelcore requires an argument\n"); + return -EINVAL; + } + /* parse kernelcore=mirror */ if (parse_option_str(p, "mirror")) { mirrored_kernelcore = true; -- 2.7.4