From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: WARN... Device 'cpu1' does not have a release() function, it is broken and must be fixed. when doing 'xl vcpu-set 1' Date: Mon, 23 Jan 2012 13:06:01 -0500 Message-ID: <20120123180601.GA24553@phenom.dumpdata.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org To: Linus Torvalds , gregkh@suse.de, linux-kernel@vger.kernel.org, kay.sievers@vrfy.org, bp@amd64.org, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, lenb@kernel.org Cc: xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org When I bring a CPU down in a guest (which should be the same as bringing a CPU down using the ACPI framework), I get this: [ 14.484206] SMP alternatives: switching to UP code [ 14.514287] ------------[ cut here ]------------ [ 14.514318] WARNING: at /home/konrad/linux-linus/drivers/base/core.c:194 device_release+0x82/0x90() [ 14.514354] Device 'cpu1' does not have a release() function, it is broken and must be fixed. [ 14.514386] Modules linked in: radeon fbcon tileblit font ttm bitblit softcursor drm_kms_helper xen_blkfront xen_netfront xen_fbfront fb_sys_fops sysimgblt sysfillrect syscopyarea xen_kbdfront xenfs xen_privcmd [ 14.514557] Pid: 22, comm: xenwatch Not tainted 3.3.0-rc1 #1 [ 14.514586] Call Trace: [ 14.515094] [] warn_slowpath_common+0x7a/0xb0 [ 14.515094] [] warn_slowpath_fmt+0x41/0x50 [ 14.515094] [] device_release+0x82/0x90 [ 14.515094] [] kobject_release+0x45/0x90 [ 14.515094] [] kobject_put+0x2c/0x60 [ 14.515094] [] put_device+0x12/0x20 [ 14.515094] [] device_unregister+0x19/0x20 [ 14.515094] [] unregister_cpu+0x4f/0x80 [ 14.515094] [] arch_unregister_cpu+0x1c/0x20 [ 14.515094] [] handle_vcpu_hotplug_event+0xc7/0xd0 [ 14.515094] [] xenwatch_thread+0xb0/0x180 [ 14.515094] [] ? wake_up_bit+0x40/0x40 [ 14.515094] [] ? split+0xf0/0xf0 [ 14.515094] [] kthread+0x96/0xa0 [ 14.515094] [] kernel_thread_helper+0x4/0x10 [ 14.515094] [] ? retint_restore_args+0x5/0x6 [ 14.515094] [] ? gs_change+0x13/0x13 [ 14.515094] ---[ end trace 8f70af51a2e2611f ]--- Looking at "commit e032d80774315869aa2285b217fdbbfed86c0b49 Author: Greg Kroah-Hartman Date: Mon Jan 16 14:40:28 2012 -0800 mce: fix warning messages about static struct mce_device " it looks like the corret fix is to make the 'cpu_devices' in arch/x86/kernel/topology.c to be changed to be more dynamic (or perhaps have an empty release function)? Is anybody else hitting this with ACPI CPU hot-unplug? Or do I have the privilige of being the first? Oh, I hadn't done a full bisection but v3.2 does not have this. The guest config is quite simple: extra="console=hvc0 debug earlyprintk=xen memblock=debug" kernel="/mnt/lab/bootstrap-x86_64/vmlinuz" ramdisk="/mnt/lab/bootstrap-x86_64/initramfs.cpio.gz" memory=1024 maxmem=2048 vcpus=2 name="bootstrap-x86_64" on_crash="preserve" vfb = [ 'vnc=1, vnclisten=0.0.0.0,vncunused=1']