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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 2D9F8C35280 for ; Fri, 8 May 2020 03:06:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 159BC20746 for ; Fri, 8 May 2020 03:06:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726770AbgEHDG5 (ORCPT ); Thu, 7 May 2020 23:06:57 -0400 Received: from gentwo.org ([3.19.106.255]:33624 "EHLO gentwo.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726661AbgEHDG5 (ORCPT ); Thu, 7 May 2020 23:06:57 -0400 Received: by gentwo.org (Postfix, from userid 1002) id 3E98C3FEDA; Fri, 8 May 2020 03:06:56 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by gentwo.org (Postfix) with ESMTP id 3CA8A3FED9; Fri, 8 May 2020 03:06:56 +0000 (UTC) Date: Fri, 8 May 2020 03:06:56 +0000 (UTC) From: Christopher Lameter X-X-Sender: cl@www.lameter.com To: Rafael Aquini cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, iamjoonsoo.kim@lge.com, rientjes@google.com, penberg@kernel.org Subject: Re: [PATCH] mm: slub: add panic_on_error to the debug facilities In-Reply-To: <20200504025138.GB18463@t490s> Message-ID: References: <20200501211540.71216-1-aquini@redhat.com> <20200504025138.GB18463@t490s> User-Agent: Alpine 2.22 (DEB 394 2020-01-19) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 3 May 2020, Rafael Aquini wrote: > On Sat, May 02, 2020 at 11:16:30PM +0000, Christopher Lameter wrote: > > On Fri, 1 May 2020, Rafael Aquini wrote: > > > > > Sometimes it is desirable to override SLUB's debug facilities > > > default behavior upon stumbling on a cache or object error > > > and just stop the execution in order to grab a coredump, at > > > the error-spotting time, instead of trying to fix the issue > > > and report in an attempt to keep the system rolling. > > > > The stopping of execution on an error is the default behavior. Usually > > you get some OOPS somewhere when data is corrupted and that causes a core > > dump. > > > > SLUB can fix the issue and continue if enabled by specifying special > > options on boot. That is *not* the default. > > > It is the default behavior when slub_debug is turned on, which is what > this patch is trying to override, when needed. We've been seeing the > need for such feature as, most often than not, by letting the system > running to crash somewhere else after hitting occurrences reported by > slub_debug ends up clobbering clues to the original issue. Ok. The backtrace is not sufficient in that case?