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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D1300C4332F for ; Wed, 2 Nov 2022 18:50:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231262AbiKBSuQ (ORCPT ); Wed, 2 Nov 2022 14:50:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43094 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231778AbiKBStm (ORCPT ); Wed, 2 Nov 2022 14:49:42 -0400 Received: from mail.skyhub.de (mail.skyhub.de [5.9.137.197]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CC6FD2BEF for ; Wed, 2 Nov 2022 11:49:32 -0700 (PDT) Received: from zn.tnic (p200300ea9733e741329c23fffea6a903.dip0.t-ipconnect.de [IPv6:2003:ea:9733:e741:329c:23ff:fea6:a903]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 683951EC0426; Wed, 2 Nov 2022 19:49:31 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1667414971; 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: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=mxQPFn4VApQbB8DR3S7WCXnD5Fw6PWq0YrvohTIv6T0=; b=DGCSacQnm9py2kWOxRnUFJJBaB/7uju6cLCKCJfO/Z57vhznDBC3OG6XXP6RT0NlNnhWVC sOBJYulAsrSlJOTdxxbR4jgCUWyH081sWheuRMz2bCZyyecu4b7HdEeP3W2jnO9JCty8bM B5fnXC7IU/UeoHh/BGRnJds8maQIOnc= Date: Wed, 2 Nov 2022 19:49:31 +0100 From: Borislav Petkov To: Eric DeVolder Cc: linux-kernel@vger.kernel.org, x86@kernel.org, kexec@lists.infradead.org, ebiederm@xmission.com, dyoung@redhat.com, bhe@redhat.com, vgoyal@redhat.com, tglx@linutronix.de, mingo@redhat.com, dave.hansen@linux.intel.com, hpa@zytor.com, nramas@linux.microsoft.com, thomas.lendacky@amd.com, robh@kernel.org, efault@gmx.de, rppt@kernel.org, david@redhat.com, sourabhjain@linux.ibm.com, konrad.wilk@oracle.com, boris.ostrovsky@oracle.com Subject: Re: [PATCH v13 7/7] x86/crash: add x86 crash hotplug support Message-ID: References: <20221031193604.28779-1-eric.devolder@oracle.com> <20221031193604.28779-8-eric.devolder@oracle.com> <1c11a429-b5a9-fb55-fbef-b49e760e2d1e@oracle.com> <06ef6e4b-1f42-d50f-1328-4f82fb34dd4d@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 02, 2022 at 11:54:08AM -0500, Eric DeVolder wrote: > Technically the answer is no; cpu hotplug events are independent of memory > hotplug events, but both are written into the elfcorehdr, so in reality > yes... The elfcorehdr contains a single list of Phdrs describing CPUs and > crash memory ranges; the entire list is re-written on a hotplug change. Then technically also yes. Otherwise your crash information will contain wrong CPU numbers. How has that not been a problem until now...? I.e., offline a bunch of CPUs and then cause a crash dump. Hmm. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette