From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57561) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Zd1P1-0001Ww-KL for qemu-devel@nongnu.org; Fri, 18 Sep 2015 15:33:00 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Zd1Oy-0007ZT-Eh for qemu-devel@nongnu.org; Fri, 18 Sep 2015 15:32:59 -0400 Date: Fri, 18 Sep 2015 16:32:52 -0300 From: Eduardo Habkost Message-ID: <20150918193252.GC4221@thinpad.lan.raisama.net> References: <1442577640-11612-1-git-send-email-armbru@redhat.com> <1442577640-11612-6-git-send-email-armbru@redhat.com> <55FC5B2E.9090504@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <55FC5B2E.9090504@redhat.com> Subject: Re: [Qemu-devel] [PATCH 5/7] qdev: Protect device-list-properties against broken devices List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Thomas Huth Cc: Peter Maydell , Peter Crosthwaite , qemu-devel@nongnu.org, qemu-stable@nongnu.org, Markus Armbruster , Christian Borntraeger , Alexander Graf , qemu-ppc@nongnu.org, Antony Pavlov , stefanha@redhat.com, Cornelia Huck , Paolo Bonzini , Alistair Francis , afaerber@suse.de, Li Guang , Richard Henderson On Fri, Sep 18, 2015 at 08:42:54PM +0200, Thomas Huth wrote: > On 18/09/15 14:00, Markus Armbruster wrote: > > Several devices don't survive object_unref(object_new(T)): they crash > > or hang during cleanup, or they leave dangling pointers behind. > > > > This breaks at least device-list-properties, because > > qmp_device_list_properties() needs to create a device to find its > > properties. Broken in commit f4eb32b "qmp: show QOM properties in > > device-list-properties", v2.1. Example reproducer: > > > > $ qemu-system-aarch64 -nodefaults -display none -machine none -S -qmp stdio > > {"QMP": {"version": {"qemu": {"micro": 50, "minor": 4, "major": 2}, "package": ""}, "capabilities": []}} > > { "execute": "qmp_capabilities" } > > {"return": {}} > > { "execute": "device-list-properties", "arguments": { "typename": "pxa2xx-pcmcia" } } > > qemu-system-aarch64: /home/armbru/work/qemu/memory.c:1307: memory_region_finalize: Assertion `((&mr->subregions)->tqh_first == ((void *)0))' failed. > > Aborted (core dumped) > > [Exit 134 (SIGABRT)] > > > > Unfortunately, I can't fix the problems in these devices right now. > > Instead, add DeviceClass member cannot_even_create_with_object_new_yet > > to mark them: > > > > * Crash or hang during cleanup (didn't debug them, so I can't say > > why): "pxa2xx-pcmcia", "realview_pci", "versatile_pci", > > "s390-sclp-event-facility", "sclp" > > > > * Dangling pointers: all CPUs, plus "allwinner-a10", "digic", > > "fsl,imx25", "fsl,imx31", "xlnx,zynqmp", because they create CPUs > > > > * Assert kvm_enabled(): "host-x86_64-cpu", host-i386-cpu", > > "host-powerpc64-cpu", "host-embedded-powerpc-cpu", > > "host-powerpc-cpu" > > I just had a look at the powerpc code - you're likely talking about > the "assert(kvm_enabled());" in the kvmppc_host_cpu_initfn() in > target-ppc/kvm.c ? That should be fine, I think, because > kvm_ppc_register_host_cpu_type() is only done on ppc when KVM has been > enabled. It's true that currently the assert() will never trigger, but we will have to eventually move class registration to type_init if we want to make a generic query-cpu-definitions implementation work properly without depending on global machine accel configuration. It won't hurt to set cannot_even_create_with_object_new_yet properly to reflect that the class isn't ready yet. -- Eduardo