From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50198) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Ze4nw-0008Et-0j for qemu-devel@nongnu.org; Mon, 21 Sep 2015 13:23:05 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Ze4nr-0003zR-Ms for qemu-devel@nongnu.org; Mon, 21 Sep 2015 13:23:03 -0400 References: <1442577640-11612-1-git-send-email-armbru@redhat.com> <1442577640-11612-6-git-send-email-armbru@redhat.com> <55FC5B2E.9090504@redhat.com> <20150918193252.GC4221@thinpad.lan.raisama.net> <87lhc0fgdb.fsf@blackfin.pond.sub.org> <560026B3.2000903@redhat.com> <874min20cp.fsf@blackfin.pond.sub.org> From: Thomas Huth Message-ID: <56003CEB.9080000@redhat.com> Date: Mon, 21 Sep 2015 19:22:51 +0200 MIME-Version: 1.0 In-Reply-To: <874min20cp.fsf@blackfin.pond.sub.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit 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: Markus Armbruster Cc: Peter Maydell , Eduardo Habkost , Peter Crosthwaite , qemu-devel@nongnu.org, qemu-stable@nongnu.org, 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 21/09/15 18:39, Markus Armbruster wrote: > Thomas Huth writes: > >> On 21/09/15 08:14, Markus Armbruster wrote: >>> Eduardo Habkost writes: >>> >>>> 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. >>> >>> Easy to verify on a KVM-capable PPC host: try -device C,help with KVM on >>> and off, where C is the appropriate host CPU. >> >> In both cases (KVM on and off), I simply get: >> >> # qemu-system-ppc64 -machine accel=tcg -device host-powerpc64-cpu,help >> 'host-powerpc64-cpu' is not a valid device model name >> # qemu-system-ppc64 -machine accel=kvm -device host-powerpc64-cpu,help >> 'host-powerpc64-cpu' is not a valid device model name >> >> No crash/abort here. > > No introspection, either. Can you try the same with QMP command > device-list-properties? # ppc64-softmmu/qemu-system-ppc64 -nodefaults -S -display none -qmp stdio {"QMP": {"version": {"qemu": {"micro": 50, "minor": 4, "major": 2}, "package": ""}, "capabilities": []}} { "execute": "qmp_capabilities" } {"return": {}} { "execute": "device-list-properties", "arguments": { "typename": "host-powerpc64-cpu" } } {"error": {"class": "DeviceNotFound", "desc": "Device 'host-powerpc64-cpu' not found"}} { "execute": "quit" } {"return": {}} {"timestamp": {"seconds": 1442856053, "microseconds": 732079}, "event": "SHUTDOWN"} # ppc64-softmmu/qemu-system-ppc64 -machine accel=kvm -nodefaults -S -display none -qmp stdio {"QMP": {"version": {"qemu": {"micro": 50, "minor": 4, "major": 2}, "package": ""}, "capabilities": []}} { "execute": "qmp_capabilities" } {"return": {}} { "execute": "device-list-properties", "arguments": { "typename": "host-powerpc64-cpu" } } {"return": [{"name": "compat", "description": "compatibility mode, power6/power7/power8", "type": "str"}]} { "execute": "quit" } {"return": {}} {"timestamp": {"seconds": 1442856113, "microseconds": 913588}, "event": "SHUTDOWN"} Thomas