From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Galbraith Subject: Re: 4.13-rc7: WARNING at arch/x86/kvm/mmu.c:717 (and a crash thereafter) Date: Mon, 28 Aug 2017 16:41:15 +0200 Message-ID: <1503931275.5701.7.camel@gmx.de> References: <1503928376.5709.11.camel@gmx.de> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT Cc: kvm@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org To: Takashi Iwai , Paolo Bonzini Return-path: In-Reply-To: <1503928376.5709.11.camel@gmx.de> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On Mon, 2017-08-28 at 15:52 +0200, Mike Galbraith wrote: > On Mon, 2017-08-28 at 14:26 +0200, Takashi Iwai wrote: > > Hi, > > > > I seem to get a kernel warning when running KVM on Dell desktop with > > IvyBridge like below. As you can see, a bad page BUG is triggered > > after that, too. The problem is not triggered always, but it happens > > occasionally. > > > > I haven't seen this on 4.13-rc4 at all, and IIRC, it started happening > > since rc5. So this might be a regression at rc5. But, as it doesn't > > happen always, I can't be 100% sure about it, and it's quite difficult > > to bisect (the test case isn't reliable), unfortunately. > > > > Any hint for further debugging this? > > Maybe a way to make failure more likely.  This is an RT kernel, but > trying to build a fat kernel over NFS from a KVM clone of my > workstation (full topology, half of ram) didn't survive one build. Bah, plain master in guest/host survived. -Mike