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=-6.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,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 114F7C282CE for ; Wed, 24 Apr 2019 17:21:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D0D8D20675 for ; Wed, 24 Apr 2019 17:21:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556126514; bh=X4mqt3B4ibRFZc+niQqIxL0uLyVVo3KTL67grXZPavM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=TVXG2vT+Ovhp7+ilnLvaOWuTFWP39IJZ7V8b9yKqHNyQQ3Le9bciS0bqx5iOetxxo qEAShk49QPa/2NNi63iU+zl2OVJH3Tb568kvqsldKo+oxE2VrtKEEILrLgl4DZiFOq yCeC12bWFb578g6wAkQpZhl8CdxBdcenkGBTT8XQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389457AbfDXRVx (ORCPT ); Wed, 24 Apr 2019 13:21:53 -0400 Received: from mail.kernel.org ([198.145.29.99]:47290 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389411AbfDXRVv (ORCPT ); Wed, 24 Apr 2019 13:21:51 -0400 Received: from localhost (62-193-50-229.as16211.net [62.193.50.229]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5B0AD205ED; Wed, 24 Apr 2019 17:21:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556126510; bh=X4mqt3B4ibRFZc+niQqIxL0uLyVVo3KTL67grXZPavM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2vcuCCZXsMWx3vbAIuKFbG+yE8l426A28IrrHmkCHaXQ3cXFNKrEgWXIdECiJ6QHY jMJ7xRSnsBI+S1EQ+8IYf+CqGhCale6KZ7oi+eGGyGJl3NGHwW7hF1LfFPjWPvVqGm Bpi+n5Eb0JRkiqhdfUBUqM0PeWkj7qvMwZQ2oNsM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Pi-Hsun Shih , Michal Hocko , Andrew Morton , Linus Torvalds , Sasha Levin Subject: [PATCH 4.4 133/168] include/linux/swap.h: use offsetof() instead of custom __swapoffset macro Date: Wed, 24 Apr 2019 19:09:37 +0200 Message-Id: <20190424170931.157236477@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190424170923.452349382@linuxfoundation.org> References: <20190424170923.452349382@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [ Upstream commit a4046c06be50a4f01d435aa7fe57514818e6cc82 ] Use offsetof() to calculate offset of a field to take advantage of compiler built-in version when possible, and avoid UBSAN warning when compiling with Clang: UBSAN: Undefined behaviour in mm/swapfile.c:3010:38 member access within null pointer of type 'union swap_header' CPU: 6 PID: 1833 Comm: swapon Tainted: G S 4.19.23 #43 Call trace: dump_backtrace+0x0/0x194 show_stack+0x20/0x2c __dump_stack+0x20/0x28 dump_stack+0x70/0x94 ubsan_epilogue+0x14/0x44 ubsan_type_mismatch_common+0xf4/0xfc __ubsan_handle_type_mismatch_v1+0x34/0x54 __se_sys_swapon+0x654/0x1084 __arm64_sys_swapon+0x1c/0x24 el0_svc_common+0xa8/0x150 el0_svc_compat_handler+0x2c/0x38 el0_svc_compat+0x8/0x18 Link: http://lkml.kernel.org/r/20190312081902.223764-1-pihsun@chromium.org Signed-off-by: Pi-Hsun Shih Acked-by: Michal Hocko Reviewed-by: Andrew Morton Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- include/linux/swap.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -135,9 +135,9 @@ struct swap_extent { /* * Max bad pages in the new format.. */ -#define __swapoffset(x) ((unsigned long)&((union swap_header *)0)->x) #define MAX_SWAP_BADPAGES \ - ((__swapoffset(magic.magic) - __swapoffset(info.badpages)) / sizeof(int)) + ((offsetof(union swap_header, magic.magic) - \ + offsetof(union swap_header, info.badpages)) / sizeof(int)) enum { SWP_USED = (1 << 0), /* is slot in swap_info[] used? */