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=-5.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, 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 09B17C4743C for ; Mon, 21 Jun 2021 21:36:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D3D9061164 for ; Mon, 21 Jun 2021 21:36:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231288AbhFUVjL (ORCPT ); Mon, 21 Jun 2021 17:39:11 -0400 Received: from server.eikelenboom.it ([91.121.65.215]:59254 "EHLO server.eikelenboom.it" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229790AbhFUVjK (ORCPT ); Mon, 21 Jun 2021 17:39:10 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=eikelenboom.it; s=20180706; h=Content-Transfer-Encoding:Content-Type: In-Reply-To:MIME-Version:Date:Message-ID:From:References:Cc:To:Subject:Sender :Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=echRYO9/03A/RWXXeBXOytrx6HhFq/gOusrcAB2T0SM=; b=QMPoXeGzyDQrsOIfNIieSIfeAg n/wxyrVCxb+cCG47obHfKhLENJth+oPCFd5VIHGVTll5N/G/9yNjsJi7Yx8F/K89OG2RDP6V+TUjY KzzBpOpGalQ7ffutRpu+8cDkyXvDBMQ3R6mVGBMc3rVAslKKuTWUD3tz8UJS5E17hAto=; Received: from 76-24-144-85.ftth.glasoperator.nl ([85.144.24.76]:35594 helo=[172.16.1.50]) by server.eikelenboom.it with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.92) (envelope-from ) id 1lvRfm-0002an-Va; Mon, 21 Jun 2021 23:41:39 +0200 Subject: Re: Linux 5.13-rc6 regression to 5.12.x: kernel OOM and panic during kernel boot in low memory Xen VM's (256MB assigned memory). To: Rasmus Villemoes , Linus Torvalds , Juergen Gross Cc: linux-kernel , "xen-devel@lists.xenproject.org" , kernel test robot References: <9108c22e-3521-9e24-6124-7776d947b788@rasmusvillemoes.dk> <0b12f27b-1109-b621-c969-10814b2c1c2f@eikelenboom.it> <7338064f-10b6-545d-bc6c-843d04aafe28@eikelenboom.it> From: Sander Eikelenboom Message-ID: Date: Mon, 21 Jun 2021 23:36:48 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: nl-NL Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 21/06/2021 18:54, Rasmus Villemoes wrote: > On 18/06/2021 03.06, Sander Eikelenboom wrote: >> On 17/06/2021 21:39, Sander Eikelenboom wrote: > >> >> OK, done some experimentation and it seems with 256M assigned to the VM >> it was almost at the edge of OOM with the 5.12 kernel as well in the >> config I am using it. >> With v5.12 when I assign 240M it boots, with 230M it doesn't. With 5.13 >> the tipping point seems to be around 265M and 270M, so my config was >> already quite close to the edge. >> >> The "direct kernel boot" feature I'm using just seems somewhat memory >> hungry, but using another compression algorithm for the kernel and >> initramfs already helped in my case. >> >> So sorry for the noise, clearly user-error. > > Hm, perhaps, but I'm still a bit nervous about that report from Oliver > Sang/kernel test robot, which was for a VM equipped with 16G of memory. > But despite quite a few attempts, I haven't been able to reproduce that > locally, so unfortunately I have no idea what's going on. > > Rasmus > Hmm I just tried to switch all VM's to a 5.13-rc7 kernel. Some worked since i reduced the size, but some still fail. The difference seems the be the number of vcpu's I assign to the VM's The ones with 1 vcpu now boot with 256MB assigned (that was what I tested before), but the ones with 2 vcpu's assigned don't and still OOM on the same kernel and initramfs that I pass in from the host. Could that box from the test-robot have a massive amount of cpu-cores and that it is some how related to that ? -- Sander