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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D39DCC433EF for ; Wed, 27 Oct 2021 11:07:11 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 95AB56023D for ; Wed, 27 Oct 2021 11:07:10 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 95AB56023D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=lists.ozlabs.org Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4HfQrF11Zgz3bXv for ; Wed, 27 Oct 2021 22:07:09 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=ellerman.id.au header.i=@ellerman.id.au header.a=rsa-sha256 header.s=201909 header.b=dXoS38tT; dkim-atps=neutral Received: from gandalf.ozlabs.org (gandalf.ozlabs.org [150.107.74.76]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4HfQqZ00Ldz2xCy for ; Wed, 27 Oct 2021 22:06:33 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=ellerman.id.au header.i=@ellerman.id.au header.a=rsa-sha256 header.s=201909 header.b=dXoS38tT; dkim-atps=neutral Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.ozlabs.org (Postfix) with ESMTPSA id 4HfQqW1c9wz4xbq; Wed, 27 Oct 2021 22:06:30 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ellerman.id.au; s=201909; t=1635332792; bh=gagwazaeXlV8j4sIKDqMdB5kheMU/VIZW2bhlG6Gp/s=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=dXoS38tTkKpP/N4OIwoklDXdvPPr7v134nTAySzQJwhwIz/4DM/j/P2DonPFZwMdi gK72PQGyHnqENBbLgHjceeACUIHMgXwUczp6Wg1Hfz4B1ohejF/xcfgDESzojv+965 ZJib5TqnOooTcShDpHPGYFzU4BiXat+n68/zM8n0K1dsYKH9/ay92tyTIEOpbmxzYM v7390YUcrC4i39pRTUl97pV62LiHj9jvMNLQw2FVUR/5R7zd0uk/Qe81r6t3W4hcht +0h/ds1OQ2nGIloBfs7vVFP5hokmknbDQ2mnO6tZ+VAp01QgeEXAjk1/WX9nKh4lz5 5iCJN+X7UQx7g== From: Michael Ellerman To: John Paul Adrian Glaubitz Subject: Re: Linux kernel: powerpc: KVM guest can trigger host crash on Power8 In-Reply-To: <04864fe5-fdd0-74b2-2bad-0303e4c2b15a@physik.fu-berlin.de> References: <87pmrtbbdt.fsf@mpe.ellerman.id.au> <05b88724-90b6-a38a-bb3b-7392f85c1934@physik.fu-berlin.de> <878ryfavaz.fsf@mpe.ellerman.id.au> <04864fe5-fdd0-74b2-2bad-0303e4c2b15a@physik.fu-berlin.de> Date: Wed, 27 Oct 2021 22:06:28 +1100 Message-ID: <874k92bubv.fsf@mpe.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: oss-security@lists.openwall.com, "debian-powerpc@lists.debian.org" , linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" John Paul Adrian Glaubitz writes: > Hi Michael! > > On 10/27/21 07:30, Michael Ellerman wrote: >> I did test the repro case you gave me before (in the bugzilla), which >> was building glibc, that passes for me with a patched host. > > Did you manage to crash the unpatched host? Yes, the parallel builds of glibc you described crashed the unpatched host 100% reliably for me. I also have a standalone reproducer I'll send you. > If the unpatched host crashes for you but the patched doesn't, I will > make sure I didn't accidentally miss anything. OK thanks. > Also, I'll try a kernel from git with Debian's config. > >> I guess we have yet another bug. >> >> I tried the following in a debian BE VM and it completed fine: >> >> $ dget -u http://ftp.debian.org/debian/pool/main/g/git/git_2.33.1-1.dsc >> $ sbuild -d sid --arch=powerpc --no-arch-all git_2.33.1-1.dsc >> >> Same for ppc64. >> >> And I also tried both at once, repeatedly in a loop. > > Did you try building gcc-11 for powerpc and ppc64 both at once? No, I will try that now. >> I guess it's something more complicated. >> >> What exact host/guest kernel versions and configs are you running? > > Both the host and guest are running Debian's stock 5.14.12 kernel. The host has > a kernel with your patches applied, the guest doesn't. OK that sounds fine. I tested upstream stable v5.14.13 + my patches, but there's nothing betwen 5.14.12 and 5.14.13 that should matter AFAICS. > Let me do some more testing. Thanks. cheers