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=-2.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_NEOMUTT 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 B805EC072B1 for ; Mon, 27 May 2019 14:02:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 922EC205ED for ; Mon, 27 May 2019 14:02:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="CJ2irMJK" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726752AbfE0OCv (ORCPT ); Mon, 27 May 2019 10:02:51 -0400 Received: from mail-lj1-f196.google.com ([209.85.208.196]:33901 "EHLO mail-lj1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726580AbfE0OCu (ORCPT ); Mon, 27 May 2019 10:02:50 -0400 Received: by mail-lj1-f196.google.com with SMTP id j24so14807381ljg.1 for ; Mon, 27 May 2019 07:02:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:date:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=nCMqcLWyCA+4Q/MEIIgUaDC50B6QNtxtBMlc97ZOozY=; b=CJ2irMJKh684KUcwCc9e3mRWyJ3si0NiJuPS8075E4MvXvGMVcYFMOXShhgQ6jQ65m 5ZT8nQuRaOztT3vV1jR1mOBIKUw3uFP111pf95gc1AWajJpwzTjYYE3a8pNrNFx8YM3G qF+VgZDKakhfXS6vsoAA15xxhlI70teCFJXoQOhdt+aB+nwDh+M1AUnaMOaH2u4iowZF M9RDJ51+OJf4FjpByIo02Fg5yIq6EfeQVZk5SdkqFnA4eQFbHfJ3XquqOWlYbMC024Gc vgdX3QYfA4UtbUxk8wiLe15FW8s3SdFjoTNbTQfmI/ASsEOrqluE4QTc3bmQiVdMTCm3 diYQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:date:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=nCMqcLWyCA+4Q/MEIIgUaDC50B6QNtxtBMlc97ZOozY=; b=bpH0tE5BSzWdw1tBM4NgdGFmHAhNnyUjF/zAQZ+hfyHzzIsFI6d0KAtZLGYeKHnNlp No6URwB4L4gHEkah5OmPMPzEyNfdhuN5/uPAaspKkJjVi6hpjxpKXrAha2ttnYZRZk/8 sUkeTLXyW5dNCKe33KezVJdQbKdS7zBJclMEeCE+LJ4sp4wZGbmB62OQfff4jaq9ox9x mw+M1mhKUtf4VL1Y3/RKv2KFj145dfR7qbaXqqFX9c+1I2VNmgcRxJ/Gr1NRSPmvWjQl r4QlaESJ4CDDYzXd14Zzg9jW5nbImXZij2O7at+ZBcqKYv+QKUchvek/w64yKAinOvxP 2mLg== X-Gm-Message-State: APjAAAX3somZB3VMRqLJ2R38lE+GdBNv4Wkd+YIZehvCuLtYBKDU4fk/ lVALLZVcDh8QmLIkUYjPySA= X-Google-Smtp-Source: APXvYqzXY+tlQxq7QCiBnJ+JYYpe6XAxMrsHVoWpLgb9r76XvPQ1r14R5z8LOJLwEgnfZ3qF0GJRWg== X-Received: by 2002:a2e:81d9:: with SMTP id s25mr21926270ljg.139.1558965768729; Mon, 27 May 2019 07:02:48 -0700 (PDT) Received: from pc636 ([37.139.158.167]) by smtp.gmail.com with ESMTPSA id r62sm2335963lja.48.2019.05.27.07.02.47 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 27 May 2019 07:02:47 -0700 (PDT) From: Uladzislau Rezki X-Google-Original-From: Uladzislau Rezki Date: Mon, 27 May 2019 16:02:40 +0200 To: Steven Rostedt Cc: "Uladzislau Rezki (Sony)" , Andrew Morton , linux-mm@kvack.org, Roman Gushchin , Hillf Danton , Michal Hocko , Matthew Wilcox , LKML , Thomas Garnier , Oleksiy Avramchenko , Joel Fernandes , Thomas Gleixner , Ingo Molnar , Tejun Heo Subject: Re: [PATCH v3 4/4] mm/vmap: move BUG_ON() check to the unlink_va() Message-ID: <20190527140240.6lzhunbc4py573yl@pc636> References: <20190527093842.10701-1-urezki@gmail.com> <20190527093842.10701-5-urezki@gmail.com> <20190527085927.19152502@gandalf.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190527085927.19152502@gandalf.local.home> User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > Move the BUG_ON()/RB_EMPTY_NODE() check under unlink_va() > > function, it means if an empty node gets freed it is a BUG > > thus is considered as faulty behaviour. > > Can we switch it to a WARN_ON(). We are trying to remove all BUG_ON()s. > If a user wants to crash on warning, there's a sysctl for that. But > crashing the system can make it hard to debug. Especially if it is hit > by someone without a serial console, and the machine just hangs in X. > That is very annoying. > > With a WARN_ON, you at least get a chance to see the crash dump. Yes we can. Even though it is considered as faulty behavior it is not a good reason to trigger a BUG. I will fix that. Thank you! -- Vlad Rezki