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 DBBD6C433E0 for ; Sat, 20 Jun 2020 10:42:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B796623B1C for ; Sat, 20 Jun 2020 10:42:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592649773; bh=vr08zGSX4iKcuVGDMstJbaasHUd8GanPlLYX4Jpo9as=; h=From:To:Cc:Subject:Date:List-ID:From; b=iTGMPg7ocQG3Pw9hBim9yeAPak5JXF2LztmeNUE/or29k7+AM3biVNj8YyL4wvQK2 yx1b3BgWFW3/gkng0jV+78uu73eEgF5aJmTFCCVNyH6irNAhCzX0eSpXJgCjWq586R ClHCWg5iNfuSP5dcjdTmLqy7TyHToHmESb1D1YTk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728010AbgFTKlq (ORCPT ); Sat, 20 Jun 2020 06:41:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:51802 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727983AbgFTKlo (ORCPT ); Sat, 20 Jun 2020 06:41:44 -0400 Received: from aquarius.haifa.ibm.com (nesher1.haifa.il.ibm.com [195.110.40.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 849D22388E; Sat, 20 Jun 2020 10:41:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592649704; bh=vr08zGSX4iKcuVGDMstJbaasHUd8GanPlLYX4Jpo9as=; h=From:To:Cc:Subject:Date:From; b=hER0vTb1Sm9lgDTW1JWJS/VHW2xTJIxy2r4/TnZ/KUb3MClGi8YgsoJUkXotTkNhe tVqtf1jZyUTnL7FlnuYaLO1MbXsmBYFkCj0XmXCPNh4g1HFZcEXjFA7fPl8Y1F6Hp/ 0QiLTkWpfJWvrnzJASXTXkftawh2ZXnq6LCRSuJc= From: Mike Rapoport To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Mike Rapoport Subject: [PATCH] sched: fix build with GCC_PLUGIN_RANDSTRUCT Date: Sat, 20 Jun 2020 13:41:36 +0300 Message-Id: <20200620104136.12195-1-rppt@kernel.org> X-Mailer: git-send-email 2.26.2 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) != | ^~~~~~~~~~~~ make[2]: *** [scripts/Makefile.build:280: kernel/smp.o] Error 1 make[1]: *** [Makefile:1764: kernel] Error 2 make[1]: *** Waiting for unfinished jobs.... make[1]: Leaving directory '/home/mike/build/kernel' make: *** [Makefile:185: __sub-make] Error 2 Move 'wake_entry' and 'wake_entry_type' fiels of task_struct out of the randomized fields to keep their layout intact. Signed-off-by: Mike Rapoport --- 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..c885573669ac 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -641,6 +641,15 @@ struct task_struct { /* -1 unrunnable, 0 runnable, >0 stopped: */ volatile long state; + /* + * The layout of these fields must match the layout CSD_TYPE_TTWU + * so they can be on the same the @call_single_queue + */ +#ifdef CONFIG_SMP + struct llist_node wake_entry; + unsigned int wake_entry_type; +#endif + /* * This begins the randomizable portion of task_struct. Only * scheduling-critical items should be added above here. @@ -654,8 +663,6 @@ struct task_struct { unsigned int ptrace; #ifdef CONFIG_SMP - struct llist_node wake_entry; - unsigned int wake_entry_type; int on_cpu; #ifdef CONFIG_THREAD_INFO_IN_TASK /* Current CPU: */ -- 2.25.4