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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 AB50AC433E0 for ; Sun, 28 Jun 2020 07:27:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7B9F0207E8 for ; Sun, 28 Jun 2020 07:27:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593329239; bh=dUqBBxgnP5eS6BruCJpKa8f5WXAIBflVt4Sm1RNBnwA=; h=From:To:Cc:Subject:Date:List-ID:From; b=EFvrdON4JRQqpumnm83EZ+dx3i1z2F1HczE2RifOp5QiB0JWQprvqzAfoq5qd+2L+ ywBov0W7QBzobKnsjcm5LV5WBPJX4GzDbVZPDKn4FMwo3WyrXRmHjOtIQKT8L5AvOp ZwcTxqOO6WP+Lrse8yDMmOSwpHCHsKW/7NBL5YIk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726116AbgF1H1S (ORCPT ); Sun, 28 Jun 2020 03:27:18 -0400 Received: from mail.kernel.org ([198.145.29.99]:60456 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725933AbgF1H1R (ORCPT ); Sun, 28 Jun 2020 03:27:17 -0400 Received: from hump.s81c.com (unknown [87.71.40.38]) (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 4EFE420768; Sun, 28 Jun 2020 07:27:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593329237; bh=dUqBBxgnP5eS6BruCJpKa8f5WXAIBflVt4Sm1RNBnwA=; h=From:To:Cc:Subject:Date:From; b=eGKjm/8Spg2HXSxSoNvLXNgD5QW5W5kh022avLDwpc2rN+s9U8bLBT3kA3XMxoUFh 9tvSF+ENB444laMXd8nyL6gn5cIRn8wAwF6RRDnbqgco3wuy8EgtrgnbLqz8ku9Jwg aQrWddyKY3yRzPJdc+beVndSmoknDG5HkGvCEVhs= From: Mike Rapoport To: Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot Cc: Kees Cook , Mike Rapoport , Steven Rostedt , Dietmar Eggemann , Ben Segall , Mel Gorman , linux-kernel@vger.kernel.org Subject: [PATCH v2] sched: fix build with GCC_PLUGIN_RANDSTRUCT Date: Sun, 28 Jun 2020 10:27:02 +0300 Message-Id: <20200628072702.1249815-1-rppt@kernel.org> X-Mailer: git-send-email 2.25.4 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 From: Mike Rapoport Since the commit a148866489fb ("sched: Replace rq::wake_list") task_struct and CSD_TYPE_TTWU objects can be on the same queue and this requires that have layout similar enough. This assumption is broken when CONFIG_GCC_PLUGIN_RANDSTRUCT is enabled: CHK include/generated/compile.h CC kernel/smp.o In file included from arch/x86/include/asm/atomic.h:5, from include/linux/atomic.h:7, from include/linux/llist.h:51, from include/linux/irq_work.h:5, from kernel/smp.c:10: kernel/smp.c: In function ‘smp_init’: include/linux/compiler.h:392:38: error: call to ‘__compiletime_assert_157’ declared with attribute error: BUILD_BUG_ON failed: offsetof(struct task_struct, wake_entry_type) - offsetof(struct task_struct, wake_entry) != offsetof(struct __call_single_data, flags) - offsetof(struct __call_single_data, llist) 392 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__) | ^ include/linux/compiler.h:373:4: note: in definition of macro ‘__compiletime_assert’ 373 | prefix ## suffix(); \ | ^~~~~~ include/linux/compiler.h:392:2: note: in expansion of macro ‘_compiletime_assert’ 392 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__) | ^~~~~~~~~~~~~~~~~~~ include/linux/build_bug.h:39:37: note: in expansion of macro ‘compiletime_assert’ 39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg) | ^~~~~~~~~~~~~~~~~~ include/linux/build_bug.h:50:2: note: in expansion of macro ‘BUILD_BUG_ON_MSG’ 50 | BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition) | ^~~~~~~~~~~~~~~~ kernel/smp.c:687:2: note: in expansion of macro ‘BUILD_BUG_ON’ 687 | BUILD_BUG_ON(offsetof(struct task_struct, wake_entry_type) - offsetof(struct task_struct, wake_entry) != | ^~~~~~~~~~~~ Wrap 'wake_entry' and 'wake_entry_type' fiels of task_struct in an anonymous struct to keep their relative layout intact during randomization. Suggested-by: Steven Rostedt Signed-off-by: Mike Rapoport --- v2: use anonymous struct as Steven suggested. include/linux/sched.h | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index b62e6aaf28f0..7e30a09df616 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -654,8 +654,15 @@ struct task_struct { unsigned int ptrace; #ifdef CONFIG_SMP - struct llist_node wake_entry; - unsigned int wake_entry_type; + /* + * The layout of these fields must match the layout of CSD_TYPE_TTWU + * so they can be on the same @call_single_queue + */ + struct { + struct llist_node wake_entry; + unsigned int wake_entry_type; + }; + int on_cpu; #ifdef CONFIG_THREAD_INFO_IN_TASK /* Current CPU: */ -- 2.25.4