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=-0.6 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, URIBL_BLOCKED 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 6E845C43334 for ; Tue, 4 Sep 2018 12:12:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 145162077C for ; Tue, 4 Sep 2018 12:12:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="TamJFqnQ"; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="W3oA9wr6" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 145162077C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727235AbeIDQhq (ORCPT ); Tue, 4 Sep 2018 12:37:46 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:38758 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726327AbeIDQhq (ORCPT ); Tue, 4 Sep 2018 12:37:46 -0400 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id 54099607DC; Tue, 4 Sep 2018 12:12:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1536063173; bh=fLmRZQ11VO7cYaYDJEesM73Gj/xoAB/Jj7saknszTFE=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=TamJFqnQf0ABfyMiGgNhfhl/hrwnPgC/CpQ1nXgiUmcgPQjsoNH1HKO8UBWreeOBg r+FWICNZ0GjVxWI2yy2fs6UEYJmO0rhy0casavqe+qqW1+es0I6Zx8TUogkYi8rzEE qlq7OX5uktQR+r4FCSXu7JObXwaIvGTQptKs7Odc= Received: from [10.204.79.100] (blr-c-bdr-fw-01_globalnat_allzones-outside.qualcomm.com [103.229.19.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: mojha@smtp.codeaurora.org) by smtp.codeaurora.org (Postfix) with ESMTPSA id EC1DB6044B; Tue, 4 Sep 2018 12:12:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1536063172; bh=fLmRZQ11VO7cYaYDJEesM73Gj/xoAB/Jj7saknszTFE=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=W3oA9wr6j6RL5W7jdIq36pxKItUPfxdBAaZLCykwkHbhYLiDQ7P8CkRXrn0n7XL3B PoP5jzXHs3wO9vIcd8fRZvpbUuOObAsJtDNMhGA/aRXEhteTeOcLLRm+E7KbmJmN3y HRIzznHQUfrWm5+WeoIwzO5rhytZLBggAMhw8c18= DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org EC1DB6044B Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=mojha@codeaurora.org Subject: Re: [PATCH] cpu/hotplug: Fix rollback during error-out in takedown_cpu() To: Neeraj Upadhyay , tglx@linutronix.de, josh@joshtriplett.org, peterz@infradead.org, mingo@kernel.org, jiangshanlai@gmail.com, dzickus@redhat.com, brendan.jackman@arm.com, malat@debian.org Cc: linux-kernel@vger.kernel.org, sramana@codeaurora.org, linux-arm-msm@vger.kernel.org References: <1536042803-6152-1-git-send-email-neeraju@codeaurora.org> From: Mukesh Ojha Message-ID: <26a4e734-088c-dbd7-30d2-34065787e925@codeaurora.org> Date: Tue, 4 Sep 2018 17:42:28 +0530 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <1536042803-6152-1-git-send-email-neeraju@codeaurora.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 9/4/2018 12:03 PM, Neeraj Upadhyay wrote: > If takedown_cpu() fails during _cpu_down(), st->state is reset, > by calling cpuhp_reset_state(). This results in an additional > increment of st->state, which results in CPUHP_AP_SMPBOOT_THREADS > state being skipped during rollback. Fix this by not calling > cpuhp_reset_state() and doing the state reset directly in > _cpu_down(). > > Fixes: 4dddfb5faa61 ("smp/hotplug: Rewrite AP state machine core") > Signed-off-by: Neeraj Upadhyay > --- > kernel/cpu.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-) > > diff --git a/kernel/cpu.c b/kernel/cpu.c > index aa7fe85..9f49edb 100644 > --- a/kernel/cpu.c > +++ b/kernel/cpu.c > @@ -970,7 +970,14 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen, > */ > ret = cpuhp_down_callbacks(cpu, st, target); > if (ret && st->state > CPUHP_TEARDOWN_CPU && st->state < prev_state) { > - cpuhp_reset_state(st, prev_state); > + /* > + * As st->last is not set, cpuhp_reset_state() increments > + * st->state, which results in CPUHP_AP_SMPBOOT_THREADS being > + * skipped during rollback. So, don't use it here. > + */ > + st->rollback = true; > + st->target = prev_state; > + st->bringup = !st->bringup; Acked-by: Mukesh Ojha looks valid for this case. > __cpuhp_kick_ap(st); > } >