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=-2.5 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 EAF4EC04EB8 for ; Wed, 12 Dec 2018 05:21:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 89BE520870 for ; Wed, 12 Dec 2018 05:21:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="F8occyx0" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 89BE520870 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com 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 S1726403AbeLLFVb (ORCPT ); Wed, 12 Dec 2018 00:21:31 -0500 Received: from mail-pl1-f195.google.com ([209.85.214.195]:42444 "EHLO mail-pl1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726218AbeLLFVa (ORCPT ); Wed, 12 Dec 2018 00:21:30 -0500 Received: by mail-pl1-f195.google.com with SMTP id y1so8037265plp.9; Tue, 11 Dec 2018 21:21:30 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=UqwenLJYzHR12uK17VPjmYMN4YNmNum/2v6HQWNppBI=; b=F8occyx0CO39MOeBWvy1Qo0s964WdOwSp1Bh8AH77tJV7Jfv0J5hrooJ0H73eEsVLG T/IWJV/bBHyn9p4zVOsPBwvOi9pWKfFzIG12liCpc6U8w1P6+XkIGpvOtZvFXCbplY6V LrR9r1VXY17txS+CSO8UD5ojBgPG1RMu7u5RdLo3QxroHXjdlzH3CCN945vnTO28RBqG lU0pktmChOn5+gXv82oDK5SAQRnjyOfOTQUAi4slWncC02Te1TpNanpGKQUpx3bLcA1t HAME194G/rF0TfEgvC7ba/ceuZUngxkhU8lyBATlY2C4R75lG/iJyc/oSjEtscPcZMjI GJuQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=UqwenLJYzHR12uK17VPjmYMN4YNmNum/2v6HQWNppBI=; b=l221ZqEDXgw79MaetKQyLKYqoXsa+vxGC76FI7z3DOwC2aRmSc2UUHqXmHLM1H4ZTd +b6U938RwzCyoH1V40uVrrhLUVYnxcq89/TVOXSgVD5pyY2xf9my7/CjKh0DoDsLVlsP kQIqOyPrUJQB7LK4DmVGiVnQSGMqOHRi/VzvI7ZyWCUiNukgMQjwwdmcEM7v/bFlDhCA 4gd+1Z2Y9+KRaJ259TFMtYpEjCpqm+p4xGtxCdIIPnSxcI7DQ/XDyqsqn5neAypRT6v6 QxLA/g8/YDR/V0GiQDzVwYdsIXsdulQdnucs+k3CET7UWHTTKzteDCvJWpz4/eqrLEW/ hGsQ== X-Gm-Message-State: AA+aEWavGubhUAR+x1CRU9FOsbp0HXnH6NGTQ8P0lLOkub4Adw5HSVAY nRRBhNauO8kvmQ8MXAAZfyg= X-Google-Smtp-Source: AFSGD/U9PTBbHSGDQxPrqtqDzAOpba2JFIIPAfuFGTgy2Vf+lwSVZ9jrr9mn+L5Hssqdj66TBa4SIw== X-Received: by 2002:a17:902:1127:: with SMTP id d36mr5551908pla.299.1544592090302; Tue, 11 Dec 2018 21:21:30 -0800 (PST) Received: from localhost ([211.246.69.141]) by smtp.gmail.com with ESMTPSA id h19sm19781344pfn.114.2018.12.11.21.21.28 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 11 Dec 2018 21:21:29 -0800 (PST) Date: Wed, 12 Dec 2018 14:21:26 +0900 From: Sergey Senozhatsky To: Daniel Wang Cc: Sergey Senozhatsky , Petr Mladek , Steven Rostedt , stable@vger.kernel.org, Alexander.Levin@microsoft.com, Andrew Morton , byungchul.park@lge.com, dave.hansen@intel.com, hannes@cmpxchg.org, jack@suse.cz, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Mathieu Desnoyers , Mel Gorman , mhocko@kernel.org, pavel@ucw.cz, penguin-kernel@i-love.sakura.ne.jp, Peter Zijlstra , tj@kernel.org, Linus Torvalds , vbabka@suse.cz, Cong Wang , Peter Feiner Subject: Re: 4.14 backport request for dbdda842fe96f: "printk: Add console owner and waiter logic to load balance console writes" Message-ID: <20181212052126.GF431@jagdpanzerIV> References: <20181003133704.43a58cf5@gandalf.local.home> <20181004074442.GA12879@jagdpanzerIV> <20181004083609.kcziz2ynwi2w7lcm@pathway.suse.cz> <20181004085515.GC12879@jagdpanzerIV> <20181022100952.GA1147@jagdpanzerIV> <20181109064740.GE599@jagdpanzerIV> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.11.1 (2018-12-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On (12/11/18 17:16), Daniel Wang wrote: > > Let's first figure out if it works. > > I would still like to try applying your patches that went into > printk.git, but for now I wonder if we can get Steven's patch into > 4.14 first, for at least we know it mitigated the issue if not > fundamentally addressed it, and we've agreed it's an innocuous change > that doesn't risk breaking stable. So... did my patch address the deadlock you are seeing or it didn't? > I haven't done this before so I'll need your help. What's the next > step to actually get Steven's patch *in* linux-4.14.y? According to > https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html > I am supposed to send an email with the patch ID and subject, which > are both mentioned in this email. Should I send another one? What's > the process like? Thanks! I'm not doing any -stable releases, so can't really answer, sorry. Probably would be better to re-address this question to 4.14 -stable maintainers. --- I guess we still don't have a really clear understanding of what exactly is going in your system. We don't even know for sure which one of the locks is deadlocking the system. And why exactly Steven's patch helps. If it is uart_port->lock, then it's one thing; if it's console_sem ->lock then it's another thing. But those two are just theories, not supported by any logs/backtraces from your systems. If it's uart_port->lock and there will be 2 patch sets to choose from for -stable, then -stable guys can pick up the one that requires less effort: 1 two-liner patch vs. 3 or 4 bigger patches. -ss