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[2620:137:e000::1:20]) by mx.google.com with ESMTP id s5-20020aa7d785000000b004cebb5c1590si5131123edq.446.2023.03.06.03.40.08; Mon, 06 Mar 2023 03:40:32 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=QUARANTINE sp=QUARANTINE dis=NONE) header.from=huawei.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229871AbjCFLdq (ORCPT + 99 others); Mon, 6 Mar 2023 06:33:46 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49720 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229901AbjCFLdl (ORCPT ); Mon, 6 Mar 2023 06:33:41 -0500 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5FF435593; Mon, 6 Mar 2023 03:33:29 -0800 (PST) Received: from dggpemm500014.china.huawei.com (unknown [172.30.72.55]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4PVbxg06k5zKq0x; Mon, 6 Mar 2023 19:31:19 +0800 (CST) Received: from localhost.localdomain (10.175.112.125) by dggpemm500014.china.huawei.com (7.185.36.153) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.21; Mon, 6 Mar 2023 19:33:21 +0800 From: Wupeng Ma To: , CC: , , , Subject: [PATCH] mm: Return early in truncate_pagecache if newsize overflows Date: Mon, 6 Mar 2023 19:33:17 +0800 Message-ID: <20230306113317.2295343-1-mawupeng1@huawei.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 X-Originating-IP: [10.175.112.125] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To dggpemm500014.china.huawei.com (7.185.36.153) X-CFilter-Loop: Reflected X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00,RCVD_IN_DNSWL_MED, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1759618354857951544?= X-GMAIL-MSGID: =?utf-8?q?1759618354857951544?= From: Ma Wupeng Our own test reports a UBSAN in truncate_pagecache: UBSAN: Undefined behaviour in mm/truncate.c:788:9 signed integer overflow: 9223372036854775807 + 1 cannot be represented in type 'long long int' Call Trace: truncate_pagecache+0xd4/0xe0 truncate_setsize+0x70/0x88 simple_setattr+0xdc/0x100 notify_change+0x654/0xb00 do_truncate+0x108/0x1a8 do_sys_ftruncate+0x2ec/0x4a0 __arm64_sys_ftruncate+0x5c/0x80 For huge file which pass LONG_MAX to ftruncate, truncate_pagecache() will be called to truncate with newsize be LONG_MAX which will lead to overflow for holebegin: loff_t holebegin = round_up(newsize, PAGE_SIZE); Since there is no meaning to truncate a file to LONG_MAX, return here to avoid burn a bunch of cpu cycles. Signed-off-by: Ma Wupeng --- mm/truncate.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/truncate.c b/mm/truncate.c index 7b4ea4c4a46b..99b6ce2d669b 100644 --- a/mm/truncate.c +++ b/mm/truncate.c @@ -730,6 +730,9 @@ void truncate_pagecache(struct inode *inode, loff_t newsize) struct address_space *mapping = inode->i_mapping; loff_t holebegin = round_up(newsize, PAGE_SIZE); + if (holebegin < 0) + return; + /* * unmap_mapping_range is called twice, first simply for * efficiency so that truncate_inode_pages does fewer