From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: kernel 4.4.2: kvm_irq_delivery_to_api / rwsem_down_read_failed Date: Mon, 22 Feb 2016 14:44:23 -0500 (EST) Message-ID: <138627702.27341861.1456170263455.JavaMail.zimbra@redhat.com> References: <56C8439F.5070901@profihost.ag> <56CB4705.1090303@redhat.com> <56CB630D.8080302@profihost.ag> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Cc: qemu-devel , kvm@vger.kernel.org To: Stefan Priebe Return-path: Received: from mx5-phx2.redhat.com ([209.132.183.37]:53635 "EHLO mx5-phx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752117AbcBVTo1 (ORCPT ); Mon, 22 Feb 2016 14:44:27 -0500 In-Reply-To: <56CB630D.8080302@profihost.ag> Sender: kvm-owner@vger.kernel.org List-ID: ----- Original Message ----- > From: "Stefan Priebe" > To: "Paolo Bonzini" , "qemu-devel" , kvm@vger.kernel.org > Sent: Monday, February 22, 2016 8:35:41 PM > Subject: Re: kernel 4.4.2: kvm_irq_delivery_to_api / rwsem_down_read_failed > > > Am 22.02.2016 um 18:36 schrieb Paolo Bonzini: > > > > > > On 20/02/2016 11:44, Stefan Priebe wrote: > >> Hi, > >> > >> while testing Kernel 4.4.2 and starting 20 Qemu 2.4.1 virtual machines. > >> I got those traces and a load of 500 on those system. I was only abler > >> to recover by sysrq-trigger. > > > > It seems like something happening at the VM level. A task took the mm > > semaphore and hung everyone else. Difficult to debug without a core > > (and without knowing who held the semaphore). Sorry. > > OK thank you anyway. Is there anything i can do if this happens again? Try grabbing a vmcore with sysrq-c, if you have kdump configured. Paolo