From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57373) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aXwPE-00064L-LF for qemu-devel@nongnu.org; Mon, 22 Feb 2016 14:44:29 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aXwPA-0006bL-Jo for qemu-devel@nongnu.org; Mon, 22 Feb 2016 14:44:28 -0500 Received: from mx5-phx2.redhat.com ([209.132.183.37]:59157) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aXwPA-0006bG-Bb for qemu-devel@nongnu.org; Mon, 22 Feb 2016 14:44:24 -0500 Date: Mon, 22 Feb 2016 14:44:23 -0500 (EST) From: Paolo Bonzini Message-ID: <138627702.27341861.1456170263455.JavaMail.zimbra@redhat.com> In-Reply-To: <56CB630D.8080302@profihost.ag> 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 Subject: Re: [Qemu-devel] kernel 4.4.2: kvm_irq_delivery_to_api / rwsem_down_read_failed List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Stefan Priebe Cc: qemu-devel , kvm@vger.kernel.org ----- 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