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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1983FC05027 for ; Sat, 4 Feb 2023 01:12:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232591AbjBDBMw (ORCPT ); Fri, 3 Feb 2023 20:12:52 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44830 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232932AbjBDBMv (ORCPT ); Fri, 3 Feb 2023 20:12:51 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E614D677B4; Fri, 3 Feb 2023 17:12:46 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 3C2A262045; Sat, 4 Feb 2023 01:12:46 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A0C7FC433B3; Sat, 4 Feb 2023 01:12:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1675473165; bh=0asfVCpuy+ETCtLElPtYddrgJX0d+emBWsKYbAvgUSg=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=NjHUnR2SMV6z1nYlDsx18pdaYVqRNoWc0qy+JZKYvWy9A2/aNWDT/Zcc1VuN3LpBk BHO7a+UWkrCbr7tIMsbiJcW08mJQrutSae8sjzbY2yTquduGD1S75JptE2V94CuHZ9 dttGDlygN+PlAgKrEnBbh02BTSkPcbJjD/mmZ2OjVdwp+2zUSzzJYuLie36CRMRH2m BCNEg1yW8DiqcrRuXnMz7q97kPUCf/igZlztYEFMXkxu4lTgwVsHT2Y4vPB+fv2I45 treDdxLfVm4Xo9kIGz/U0PB3fSsQxF7GAvG09BPdoaWSqVqEDw/Bl5+LonXCOZV8EM 8X69FQT7ZO2hA== Received: by mail-ej1-f43.google.com with SMTP id me3so19972308ejb.7; Fri, 03 Feb 2023 17:12:45 -0800 (PST) X-Gm-Message-State: AO0yUKW/dqF4r+NlFvJf02FENnxf+zlqZzdHCjmvztJVP+OClSd11Lby BJbZuQsXDCT/4yBXfGaM8t9kttWTlIRK73BtbzA= X-Google-Smtp-Source: AK7set8d2wN/FrByoELlHyIqk75D2M0EbNicNZv8b+fs1zPJUylkd4dAYoofH/2BIYKRkzzgrVhuEwXH3PfZW7NSuUo= X-Received: by 2002:a17:906:8419:b0:884:c19c:7c6 with SMTP id n25-20020a170906841900b00884c19c07c6mr3300870ejx.120.1675473163646; Fri, 03 Feb 2023 17:12:43 -0800 (PST) MIME-Version: 1.0 References: In-Reply-To: From: Guo Ren Date: Sat, 4 Feb 2023 09:12:31 +0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH 05/22] csky/cpu: Make sure arch_cpu_idle_dead() doesn't return To: Josh Poimboeuf Cc: linux-kernel@vger.kernel.org, jgross@suse.com, richard.henderson@linaro.org, ink@jurassic.park.msu.ru, mattst88@gmail.com, linux-alpha@vger.kernel.org, linux@armlinux.org.uk, linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com, will@kernel.org, linux-csky@vger.kernel.org, linux-ia64@vger.kernel.org, chenhuacai@kernel.org, kernel@xen0n.name, loongarch@lists.linux.dev, f.fainelli@gmail.com, bcm-kernel-feedback-list@broadcom.com, tsbogend@alpha.franken.de, linux-mips@vger.kernel.org, jiaxun.yang@flygoat.com, mpe@ellerman.id.au, npiggin@gmail.com, christophe.leroy@csgroup.eu, linuxppc-dev@lists.ozlabs.org, ysato@users.sourceforge.jp, dalias@libc.org, linux-sh@vger.kernel.org, davem@davemloft.net, sparclinux@vger.kernel.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, chris@zankel.net, jcmvbkbc@gmail.com, linux-xtensa@linux-xtensa.org, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, vschneid@redhat.com, paulmck@kernel.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-csky@vger.kernel.org On Sat, Feb 4, 2023 at 6:05 AM Josh Poimboeuf wrote: > > arch_cpu_idle_dead() doesn't return. Make that more explicit with a > BUG(). > > BUG() is preferable to unreachable() because BUG() is a more explicit > failure mode and avoids undefined behavior like falling off the edge of > the function into whatever code happens to be next. > > Signed-off-by: Josh Poimboeuf > --- > arch/csky/kernel/smp.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/arch/csky/kernel/smp.c b/arch/csky/kernel/smp.c > index b45d1073307f..0ec20efaf5fd 100644 > --- a/arch/csky/kernel/smp.c > +++ b/arch/csky/kernel/smp.c > @@ -317,5 +317,7 @@ void arch_cpu_idle_dead(void) > "jmpi csky_start_secondary" > : > : "r" (secondary_stack)); > + > + BUG(); Why not: diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c index f26ab2675f7d..1d3bf903add2 100644 --- a/kernel/sched/idle.c +++ b/kernel/sched/idle.c @@ -285,6 +285,7 @@ static void do_idle(void) tick_nohz_idle_stop_tick(); cpuhp_report_idle_dead(); arch_cpu_idle_dead(); + BUG(); } arch_cpu_idle_enter(); > } > #endif > -- > 2.39.0 > -- Best Regards Guo Ren