From mboxrd@z Thu Jan 1 00:00:00 1970 From: Cornelia Huck Subject: Re: [PATCH v4 3/6] KVM: Initialize irqfd from kvm_init(). Date: Wed, 3 Apr 2013 13:32:26 +0200 Message-ID: <20130403133226.6d92c671@gondolin> References: <1362043352-56889-1-git-send-email-cornelia.huck@de.ibm.com> <1362043352-56889-4-git-send-email-cornelia.huck@de.ibm.com> <515B7A95.6020800@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: Marcelo Tosatti , Gleb Natapov , Christian Borntraeger , Carsten Otte , Alexander Graf , Heiko Carstens , Martin Schwidefsky , "Michael S. Tsirkin" , KVM , linux-s390 , qemu-devel , Tejun Heo To: Sasha Levin Return-path: Received: from e06smtp18.uk.ibm.com ([195.75.94.114]:34937 "EHLO e06smtp18.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759558Ab3DCLch (ORCPT ); Wed, 3 Apr 2013 07:32:37 -0400 Received: from /spool/local by e06smtp18.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 3 Apr 2013 12:29:22 +0100 In-Reply-To: <515B7A95.6020800@oracle.com> Sender: kvm-owner@vger.kernel.org List-ID: On Tue, 02 Apr 2013 20:40:53 -0400 Sasha Levin wrote: > On 02/28/2013 04:22 AM, Cornelia Huck wrote: > > Currently, eventfd introduces module_init/module_exit functions > > to initialize/cleanup the irqfd workqueue. This only works, however, > > if no other module_init/module_exit functions are built into the > > same module. > > > > Let's just move the initialization and cleanup to kvm_init and kvm_exit. > > This way, it is also clearer where kvm startup may fail. > > > > Signed-off-by: Cornelia Huck > > I'm seeing this during boot: > > [ 6.763302] ------------[ cut here ]------------ > [ 6.763763] WARNING: at kernel/workqueue.c:4204 destroy_workqueue+0x1df/0x3d0() > [ 6.764507] Modules linked in: > [ 6.764792] Pid: 1, comm: swapper/0 Tainted: G W 3.9.0-rc5-next-20130402-sasha-00015-g3522ec5 #324 > [ 6.765654] Call Trace: > [ 6.765875] [] warn_slowpath_common+0x8b/0xc0 > [ 6.766436] [] warn_slowpath_null+0x15/0x20 > [ 6.766947] [] destroy_workqueue+0x1df/0x3d0 > [ 6.768631] [] kvm_irqfd_exit+0x10/0x20 > [ 6.770000] [] kvm_init+0x2ab/0x310 > [ 6.770607] [] ? cpu_has_kvm_support+0x4d/0x4d > [ 6.771241] [] vmx_init+0x1f4/0x437 > [ 6.771709] [] ? cpu_has_kvm_support+0x4d/0x4d > [ 6.772266] [] do_one_initcall+0xb2/0x1b0 > [ 6.772995] [] kernel_init_freeable+0x15d/0x1ef > [ 6.773857] [] ? loglevel+0x31/0x31 > [ 6.774609] [] ? rest_init+0x140/0x140 > [ 6.775551] [] kernel_init+0x9/0xf0 > [ 6.776162] [] ret_from_fork+0x7c/0xb0 > [ 6.776662] [] ? rest_init+0x140/0x140 > [ 6.777241] ---[ end trace 10bba684ced4346a ]--- > > And I think it has something to do with this patch. What this patch does is move initialization of the workqueue - the code called should be indentical. The workqueue created/destroyed should not have been touched (no irqfds yet), but the new workqueue code seems to encounter something unexpected. I'd expect destroy_workqueue() to be callable after a successful create_singlethread_workqueue(). Tejun? > > > Thanks, > Sasha >