From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752248AbcJDEMv (ORCPT ); Tue, 4 Oct 2016 00:12:51 -0400 Received: from mail-oi0-f53.google.com ([209.85.218.53]:36502 "EHLO mail-oi0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751150AbcJDEMu (ORCPT ); Tue, 4 Oct 2016 00:12:50 -0400 MIME-Version: 1.0 In-Reply-To: <20161003210729.e4c39a86b8e8e4d103715c7d@linux-foundation.org> References: <20161003210729.e4c39a86b8e8e4d103715c7d@linux-foundation.org> From: Linus Torvalds Date: Mon, 3 Oct 2016 21:12:48 -0700 X-Google-Sender-Auth: RfoiHNNHFy_UYmXmbZJRkvYEREU Message-ID: Subject: Re: BUG_ON() in workingset_node_shadows_dec() triggers To: Andrew Morton Cc: Johannes Weiner , Antonio SJ Musumeci , Miklos Szeredi , Linux Kernel Mailing List , stable Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 3, 2016 at 9:07 PM, Andrew Morton wrote: > > Well, it's a VM_BUG_ON and few people run with CONFIG_DEBUG_VM. Ehh. If by "few people" you mean "pretty much everybody", you'd be right, but your choice of wording would be somewhat misleading, wouldn't you say? Hint: here's a line from the standard Fedora kernel config: CONFIG_DEBUG_VM=y so *no*. VM_BUG_ON() is no less deadly than a regular BUG_ON(). It just allows some people to build smaller kernels, but apparently distro people would rather have debugging than save a few kB of RAM. The VM debvugging code has VM_WARN_ON() and VM_WARN_ON_ONCE() for people who want to get a "oops, my assumptions were wrong" Killing machines because somebody made an assumption that was wrong is not ok. Killing the machine is ok if we have a situation where there literally is no other choice. Linus