From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <SRS0=Fmhj=NM=vger.kernel.org=linux-kernel-owner@kernel.org>
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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,
	MAILING_LIST_MULTI,SPF_PASS,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 79BA3C0044C
	for <linux-kernel@archiver.kernel.org>; Thu,  1 Nov 2018 18:46:29 +0000 (UTC)
Received: from vger.kernel.org (vger.kernel.org [209.132.180.67])
	by mail.kernel.org (Postfix) with ESMTP id 289F62082E
	for <linux-kernel@archiver.kernel.org>; Thu,  1 Nov 2018 18:46:29 +0000 (UTC)
DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 289F62082E
Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.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 S1727752AbeKBDuh (ORCPT
        <rfc822;linux-kernel@archiver.kernel.org>);
        Thu, 1 Nov 2018 23:50:37 -0400
Received: from mail.kernel.org ([198.145.29.99]:41616 "EHLO mail.kernel.org"
        rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
        id S1725961AbeKBDuh (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
        Thu, 1 Nov 2018 23:50:37 -0400
Received: from gandalf.local.home (cpe-66-24-56-78.stny.res.rr.com [66.24.56.78])
        (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
        (No client certificate requested)
        by mail.kernel.org (Postfix) with ESMTPSA id 000FD2064C;
        Thu,  1 Nov 2018 18:46:24 +0000 (UTC)
Date:   Thu, 1 Nov 2018 14:46:23 -0400
From:   Steven Rostedt <rostedt@goodmis.org>
To:     Thomas Gleixner <tglx@linutronix.de>
Cc:     Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
        Peter Zijlstra <peterz@infradead.org>,
        "Paul E . McKenney" <paulmck@linux.vnet.ibm.com>,
        Boqun Feng <boqun.feng@gmail.com>,
        linux-kernel@vger.kernel.org, linux-api@vger.kernel.org,
        Andy Lutomirski <luto@amacapital.net>,
        Dave Watson <davejwatson@fb.com>, Paul Turner <pjt@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Russell King <linux@arm.linux.org.uk>,
        Ingo Molnar <mingo@redhat.com>,
        "H . Peter Anvin" <hpa@zytor.com>,
        Andi Kleen <andi@firstfloor.org>, Chris Lameter <cl@linux.com>,
        Ben Maurer <bmaurer@fb.com>,
        Josh Triplett <josh@joshtriplett.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>,
        Michael Kerrisk <mtk.manpages@gmail.com>,
        Joel Fernandes <joelaf@google.com>,
        Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
        Matthew Wilcox <mawilcox@microsoft.com>
Subject: Re: [RFC PATCH for 4.21 03/16] mm: Replace BUG_ON() by WARN_ON() in
 vm_unmap_ram()
Message-ID: <20181101144623.61d43102@gandalf.local.home>
In-Reply-To: <alpine.DEB.2.21.1811011320160.1642@nanos.tec.linutronix.de>
References: <20181101095844.24462-1-mathieu.desnoyers@efficios.com>
        <20181101095844.24462-4-mathieu.desnoyers@efficios.com>
        <alpine.DEB.2.21.1811011320160.1642@nanos.tec.linutronix.de>
X-Mailer: Claws Mail 3.16.0 (GTK+ 2.24.32; x86_64-pc-linux-gnu)
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Thu, 1 Nov 2018 13:21:12 +0100 (CET)
Thomas Gleixner <tglx@linutronix.de> wrote:

> Mathieu,
> 
> On Thu, 1 Nov 2018, Mathieu Desnoyers wrote:
> 
> > It is encouraged to warn and return rather than use BUG_ON() when
> > the condition can be recovered from in ways that are more graceful than
> > halting the whole system.  
> 
> You're failing to desribe how that graceful recovery works.
> 

I think the graceful recovery is to simply return:

	if (WARN_ON(cond))
		return;

is better than just

	BUG_ON(cond);

As that's what Linus made pretty clear at the Maintainer's Summit.

-- Steve