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=-2.1 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 EAEADC43144 for ; Tue, 26 Jun 2018 04:22:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 99497264D8 for ; Tue, 26 Jun 2018 04:22:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="leZqQJ8/" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 99497264D8 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 S1751079AbeFZEWP (ORCPT ); Tue, 26 Jun 2018 00:22:15 -0400 Received: from mail-pg0-f66.google.com ([74.125.83.66]:35881 "EHLO mail-pg0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750923AbeFZEWN (ORCPT ); Tue, 26 Jun 2018 00:22:13 -0400 Received: by mail-pg0-f66.google.com with SMTP id m5-v6so7041108pgd.3; Mon, 25 Jun 2018 21:22:13 -0700 (PDT) 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=szF8TaYKotUnPfMK9dcCkI6FOs931Ofcy5Mcbo7b+X0=; b=leZqQJ8/kia35ohLpoE4Agsdz0MwafU18t7AernzByVkM+1MIS1raPjMa7d/OTkag5 yp3rwot4VP9W1UrScKaY8gwVojDIWzUmN7lBj5MgteIa6OjHpZA0ktoZDhCiQbAJtOhT AKoM1/7dA/mmpME07hb7Q5GBSdRKT0SGxTyWPvt1XgdWM2bqQPGP7eVDn8C/G68CKrQu xTquhHgGgt2nlpl8IpIwwv2AVskeqvjgDxZjmRBlrafJRDVNLSPWqEXfrl5Y4u//1QqQ CW9cZEcq0CPM+qhV56tpDB5CXtDwF435K+46jfmIqWe0U5dsqVBkJDImq6Uvdxn8dwmj lzbA== 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=szF8TaYKotUnPfMK9dcCkI6FOs931Ofcy5Mcbo7b+X0=; b=Gp/C1wFvGIjIsromKOaJNoo3YI44oNY2fzKA/4aW3p8PnDKzDZfyUWp6ex2K/T8bTM HAIhfy57ejOXkUzjJjRU/6I/sPfxLyhdXUj3LFU6Rqsm6w218AEO2Tuytiqw2LCg7q5p JzfdMUmGXRv5yc2IN4RSBpxFMWssKaD4OldICv36DnX6yfaYGHmktdm50H4LxuaAzuCf IQOGvGZpy3hL83zArloBP7QILycGd+aV3p3/y0/LVICDh8U9c/0FiA0RgJp+SnTXwYZK bdTvyc1UzgVpxRTW3YFXQK5xm+XbVIjEI3QLNns7KvNKfgfioiKMfvENmZc+GyHaeFaA bGZQ== X-Gm-Message-State: APt69E03XIDgltlyyZjZspt7xLdxJTxQoDuxM+2o1dfl/iS75uhNdUfO Uyp0cG+ala+jCW67tcfVWmg= X-Google-Smtp-Source: ADUXVKJcm/aXC6lGzFBW/1lPK5suG3n9aiYRIm2KCQD/Ks6vI4USdNXk1ozxTTJ+k0Flh/rZJBp0eA== X-Received: by 2002:a62:5c47:: with SMTP id q68-v6mr3640822pfb.81.1529986932845; Mon, 25 Jun 2018 21:22:12 -0700 (PDT) Received: from localhost ([175.223.48.122]) by smtp.gmail.com with ESMTPSA id f123-v6sm925536pfc.4.2018.06.25.21.22.10 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 25 Jun 2018 21:22:11 -0700 (PDT) Date: Tue, 26 Jun 2018 13:22:08 +0900 From: Sergey Senozhatsky To: Steven Rostedt Cc: Sergey Senozhatsky , syzbot , linux-kernel@vger.kernel.org, pmladek@suse.com, sergey.senozhatsky@gmail.com, syzkaller-bugs@googlegroups.com, Samuel Ortiz , "David S. Miller" , linux-wireless@vger.kernel.org, netdev@vger.kernel.org Subject: Re: INFO: rcu detected stall in vprintk_emit Message-ID: <20180626042208.GA31439@jagdpanzerIV> References: <000000000000720530056f7f9b63@google.com> <20180626014924.GB11229@jagdpanzerIV> <20180625225937.43aee76c@vmware.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180625225937.43aee76c@vmware.local.home> User-Agent: Mutt/1.10.0 (2018-05-17) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On (06/25/18 22:59), Steven Rostedt wrote: > > Or ratelimited error reporting and cond_resched() > > [that would be option B]: > > I don't think this is a printk() issue per se, so I think Option B is > the only option. You should not get stuck in an infinite loop if we run > short on memory. Perhaps we could have an Option C which would exit > this loop gracefully with some kind of error. But I haven't looked at > the surrounding code to be sure if that is possible. Agree. I like Option B - an endless loop is the root cause, at the same time filling up logbuf with useless data is useless. Can't tell if Option C is feasible, up to networking people. -ss