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=-8.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,UNPARSEABLE_RELAY, USER_AGENT_GIT 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 9B37DC6786F for ; Thu, 1 Nov 2018 17:00:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 64AD62081B for ; Thu, 1 Nov 2018 17:00:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 64AD62081B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=mediatek.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 S1727521AbeKBCEP (ORCPT ); Thu, 1 Nov 2018 22:04:15 -0400 Received: from mailgw01.mediatek.com ([210.61.82.183]:62587 "EHLO mailgw01.mediatek.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1725982AbeKBCEP (ORCPT ); Thu, 1 Nov 2018 22:04:15 -0400 X-UUID: 3963096f438c4c29b4b5f2f4c69d258f-20181102 X-UUID: 3963096f438c4c29b4b5f2f4c69d258f-20181102 Received: from mtkcas08.mediatek.inc [(172.21.101.126)] by mailgw01.mediatek.com (envelope-from ) (mhqrelay.mediatek.com ESMTP with TLS) with ESMTP id 1551470932; Fri, 02 Nov 2018 01:00:16 +0800 Received: from mtkcas07.mediatek.inc (172.21.101.84) by mtkmbs08n1.mediatek.inc (172.21.101.55) with Microsoft SMTP Server (TLS) id 15.0.1395.4; Fri, 2 Nov 2018 01:00:09 +0800 Received: from mtksdccf07.mediatek.inc (172.21.84.99) by mtkcas07.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1395.4 via Frontend Transport; Fri, 2 Nov 2018 01:00:08 +0800 From: To: Andrew Morton , Michal Hocko , Joe Perches , Matthew Wilcox CC: , , , , , Miles Chen , Michal Hocko Subject: [PATCH v4] mm/page_owner: clamp read count to PAGE_SIZE Date: Fri, 2 Nov 2018 01:00:07 +0800 Message-ID: <1541091607-27402-1-git-send-email-miles.chen@mediatek.com> X-Mailer: git-send-email 1.9.1 MIME-Version: 1.0 Content-Type: text/plain X-MTK: N Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Miles Chen The page owner read might allocate a large size of memory with a large read count. Allocation fails can easily occur when doing high order allocations. Clamp buffer size to PAGE_SIZE to avoid arbitrary size allocation and avoid allocation fails due to high order allocation. Change since v3: - remove the change in kvmalloc - keep kmalloc in page_owner.c Change since v2: - improve kvmalloc, allow sub page allocations fallback to vmalloc when CONFIG_HIGHMEM=y Change since v1: - use kvmalloc() - clamp buffer size to PAGE_SIZE Signed-off-by: Miles Chen Cc: Joe Perches Cc: Matthew Wilcox Cc: Michal Hocko --- mm/page_owner.c | 1 + 1 file changed, 1 insertion(+) diff --git a/mm/page_owner.c b/mm/page_owner.c index 87bc0dfdb52b..b83f295e4eca 100644 --- a/mm/page_owner.c +++ b/mm/page_owner.c @@ -351,6 +351,7 @@ print_page_owner(char __user *buf, size_t count, unsigned long pfn, .skip = 0 }; + count = count > PAGE_SIZE ? PAGE_SIZE : count; kbuf = kmalloc(count, GFP_KERNEL); if (!kbuf) return -ENOMEM; -- 2.18.0