From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f197.google.com (mail-pf0-f197.google.com [209.85.192.197]) by kanga.kvack.org (Postfix) with ESMTP id B01632806DC for ; Fri, 19 May 2017 10:40:47 -0400 (EDT) Received: by mail-pf0-f197.google.com with SMTP id p74so57164661pfd.11 for ; Fri, 19 May 2017 07:40:47 -0700 (PDT) Received: from mail-pg0-x241.google.com (mail-pg0-x241.google.com. [2607:f8b0:400e:c05::241]) by mx.google.com with ESMTPS id o61si110425plb.81.2017.05.19.07.40.46 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 19 May 2017 07:40:46 -0700 (PDT) Received: by mail-pg0-x241.google.com with SMTP id s62so10011133pgc.0 for ; Fri, 19 May 2017 07:40:46 -0700 (PDT) From: Firo Yang Subject: [PATCH] mm, vmstat: Fix NULL pointer dereference during pagetypeinfo print Date: Fri, 19 May 2017 22:39:36 +0800 Message-Id: <20170519143936.21209-1-firogm@gmail.com> Sender: owner-linux-mm@kvack.org List-ID: To: akpm@linux-foundation.org Cc: vbabka@suse.cz, mgorman@techsingularity.net, hannes@cmpxchg.org, mhocko@suse.com, bigeasy@linutronix.de, iamjoonsoo.kim@lge.com, rientjes@google.com, hughd@google.com, cl@linux.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Firo Yang During showing the pagetypeinfo, we forgot to save the found page and dereference a invalid page address from the stack. To fix it, save and reference the page address returned by pfn_to_online_page(). Signed-off-by: Firo Yang --- mm/vmstat.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/vmstat.c b/mm/vmstat.c index c432e58..6dae6b2 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -1223,7 +1223,8 @@ static void pagetypeinfo_showblockcount_print(struct seq_file *m, for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) { struct page *page; - if (!pfn_to_online_page(pfn)) + page = pfn_to_online_page(pfn); + if (!page) continue; /* Watch for unexpected holes punched in the memmap */ -- 2.9.4 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org