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=-0.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 BDE86C35280 for ; Fri, 1 May 2020 21:42:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 997CF208DB for ; Fri, 1 May 2020 21:42:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="aL3yjS0q" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726762AbgEAVmA (ORCPT ); Fri, 1 May 2020 17:42:00 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:26638 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726366AbgEAVmA (ORCPT ); Fri, 1 May 2020 17:42:00 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1588369319; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=OdOcvEZEhBr5Vq54X6k0G7YOitkQMN27mIGgBJ6KgyU=; b=aL3yjS0qISPNDayMSOf/6lJ6Syxijao+toJeIIG6MoVFZpFrT0FjeI+l1XTNrIVmj/3Fkt bRAQFQgYUcQRVqHcUGKgDyHZfHWO2PGC/TYOmlebT6VY20Ph3e6NqrutnWu7pJoCS2DSwQ EKp7U/doxPf1zTWIxpDPpDR0q/lXMiY= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-168-Sy8kGdfPMBuS2MOlTZVIJA-1; Fri, 01 May 2020 17:41:52 -0400 X-MC-Unique: Sy8kGdfPMBuS2MOlTZVIJA-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 4A16645F; Fri, 1 May 2020 21:41:50 +0000 (UTC) Received: from optiplex-lnx (unknown [10.3.128.26]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A01BD5EE11; Fri, 1 May 2020 21:41:47 +0000 (UTC) Date: Fri, 1 May 2020 17:41:44 -0400 From: Rafael Aquini To: Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, iamjoonsoo.kim@lge.com, rientjes@google.com, penberg@kernel.org, cl@linux.com Subject: Re: [PATCH] mm: slub: add panic_on_error to the debug facilities Message-ID: <20200501214144.GD27720@optiplex-lnx> References: <20200501211540.71216-1-aquini@redhat.com> <20200501143751.97a25bb7f89f8d93ec443868@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200501143751.97a25bb7f89f8d93ec443868@linux-foundation.org> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 01, 2020 at 02:37:51PM -0700, Andrew Morton wrote: > On Fri, 1 May 2020 17:15:40 -0400 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. > > > > This patch introduces a new debug flag SLAB_PANIC_ON_ERROR, > > along with its related SLUB-machinery, in order to extend > > current slub_debug facilites and provide the aforementioned > > behavior override. > > > > Sees reasonable. > > > --- a/Documentation/vm/slub.rst > > +++ b/Documentation/vm/slub.rst > > @@ -54,6 +54,8 @@ Possible debug options are:: > > caused higher minimum slab orders > > - Switch all debugging off (useful if the kernel is > > configured with CONFIG_SLUB_DEBUG_ON) > > + C Toggle panic on error (crash) to allow for post-mortem > > + analysis of a coredump taken at the error-spotting time > > nit: "toggle" means to switch to the other state. But what we're doing > here is to set to the "on" state. This: > Thanks Andrew, that's indeed much better. > --- a/Documentation/vm/slub.rst~mm-slub-add-panic_on_error-to-the-debug-facilities-fix > +++ a/Documentation/vm/slub.rst > @@ -49,12 +49,12 @@ Possible debug options are:: > P Poisoning (object and padding) > U User tracking (free and alloc) > T Trace (please only use on single slabs) > - A Toggle failslab filter mark for the cache > + A Enable failslab filter mark for the cache > O Switch debugging off for caches that would have > caused higher minimum slab orders > - Switch all debugging off (useful if the kernel is > configured with CONFIG_SLUB_DEBUG_ON) > - C Toggle panic on error (crash) to allow for post-mortem > + C Enable panic on error (crash) to allow for post-mortem > analysis of a coredump taken at the error-spotting time > > F.e. in order to boot just with sanity checks and red zoning one would specify:: > _ > >