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=-0.9 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID 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 A8C24C28CF6 for ; Fri, 3 Aug 2018 18:57:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4A3312178F for ; Fri, 3 Aug 2018 18:57:27 +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="eM/fxtgO"; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="cAfwhetZ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4A3312178F 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 S1731912AbeHCUy4 (ORCPT ); Fri, 3 Aug 2018 16:54:56 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:49834 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727953AbeHCUy4 (ORCPT ); Fri, 3 Aug 2018 16:54:56 -0400 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id 69A92606AC; Fri, 3 Aug 2018 18:57:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1533322644; bh=H9RBKus/Nz9f9wTR4WXVqIPEF4TzraGWqCzhFdHYC7w=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=eM/fxtgOq5mCw3AT2RpmtHtFy0WDXFyGnvSptMJj7k72KyyKS9RFzwvJW26T6GPOr M8HP85VruDgo4nOmtgmWvz+WwQZ8U4ZUjjFbHlmcAkwYrJriutQx6hoptinuP6/13P N3Ndi9VkqRVYjBWvHCmqW5PNhXpYQtYJsbDM1hG0= Received: from mail.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.codeaurora.org (Postfix) with ESMTP id BCC4E60224; Fri, 3 Aug 2018 18:57:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1533322643; bh=H9RBKus/Nz9f9wTR4WXVqIPEF4TzraGWqCzhFdHYC7w=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=cAfwhetZe8C63fxWJpkJCGNusAhpdcUgmqJYYKTvpUY7iQNsuRrERhSR732siHxxX H7coPRaM9h+T98ppz3e3G9RFEOumfx+zm8WxxUJZu1dddlgZeoVEfO4jBiHvYxnk/r loQ3neQNNR+IZHgoJKgcUjjafxBbM/n/H+uMOjMk= MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Fri, 03 Aug 2018 11:57:23 -0700 From: Sodagudi Prasad To: Thomas Gleixner Cc: Peter Zijlstra , mingo@kernel.org, gregkh@linuxfoundation.org, bigeasy@linutronix.de, isaacm@codeaurora.org, linux-kernel@vger.kernel.org Subject: Re: cpu stopper threads and setaffinity leads to deadlock In-Reply-To: References: <24eebe1d874cb8e3b9a18087554544fa@codeaurora.org> <20180802094908.GK2494@hirez.programming.kicks-ass.net> Message-ID: <712493a7926b0f58543be052ced95db9@codeaurora.org> X-Sender: psodagud@codeaurora.org User-Agent: Roundcube Webmail/1.2.5 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2018-08-03 04:41, Thomas Gleixner wrote: > Prasad. > > On Thu, 2 Aug 2018, Peter Zijlstra wrote: >> >> So why didn't you do the 'obvious' parallel to what you did for >> cpu_stop_queue_two_works(), namely: > > Is that patch fixing the issue for you? Hi Thomas and Peter, Yes. Tested both versions of patches and both variants are working on Qualcomm devices with stress testing of set affinity and tasks cross-migration, which were previously leading to the deadlock. -Thanks, Prasad > >> --- a/kernel/stop_machine.c >> +++ b/kernel/stop_machine.c >> @@ -81,6 +81,7 @@ static bool cpu_stop_queue_work(unsigned >> unsigned long flags; >> bool enabled; >> >> + preempt_disable(); >> raw_spin_lock_irqsave(&stopper->lock, flags); >> enabled = stopper->enabled; >> if (enabled) >> @@ -90,6 +91,7 @@ static bool cpu_stop_queue_work(unsigned >> raw_spin_unlock_irqrestore(&stopper->lock, flags); >> >> wake_up_q(&wakeq); >> + preempt_enable(); >> >> return enabled; >> } >> -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, Linux Foundation Collaborative Project