From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf1-f197.google.com (mail-pf1-f197.google.com [209.85.210.197]) by kanga.kvack.org (Postfix) with ESMTP id CF1698E0001 for ; Tue, 18 Sep 2018 11:34:47 -0400 (EDT) Received: by mail-pf1-f197.google.com with SMTP id h65-v6so1239452pfk.18 for ; Tue, 18 Sep 2018 08:34:47 -0700 (PDT) Received: from mail5.wrs.com (mail5.windriver.com. [192.103.53.11]) by mx.google.com with ESMTPS id j64-v6si16769326pgc.88.2018.09.18.08.34.46 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 18 Sep 2018 08:34:46 -0700 (PDT) From: Subject: [PATCH] mm/page_alloc: Fix panic caused by passing debug_guardpage_minorder or kernelcore to command line Date: Tue, 18 Sep 2018 23:33:08 +0800 Message-ID: <1537284788-428784-1-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 Cc: 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+ #1 [ 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 --- mm/page_alloc.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 89d2a2a..d4cda06 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -14,6 +14,8 @@ * (lots of bits borrowed from Ingo Molnar & Andrew Morton) */ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + #include #include #include @@ -630,6 +632,11 @@ static int __init debug_guardpage_minorder_setup(char *buf) { unsigned long res; + if (!buf) { + pr_err("Config string not provided\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 +6959,11 @@ static int __init cmdline_parse_core(char *p, unsigned long *core, */ static int __init cmdline_parse_kernelcore(char *p) { + if (!p) { + pr_err("Config string not provided\n"); + return -EINVAL; + } + /* parse kernelcore=mirror */ if (parse_option_str(p, "mirror")) { mirrored_kernelcore = true; -- 2.7.4