path: root/target-microblaze/cpu.c
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authorMarkus Armbruster <armbru@redhat.com>2015-10-01 10:59:58 +0200
committerMarkus Armbruster <armbru@redhat.com>2015-10-09 15:25:57 +0200
commit4c315c27661502a0813b129e41c0bf640c34a8d6 (patch)
treec7eee2c3609eaf7743ed256a70c18c9d0916ca2a /target-microblaze/cpu.c
parentedb1523d90415cb79f60f83b4028ef3820d15612 (diff)
qdev: Protect device-list-properties against broken devices
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_destroy_with_object_finalize_yet to mark them: * Hang during cleanup (didn't debug, so I can't say why): "realview_pci", "versatile_pci". * Dangling pointer in cpus: most CPUs, plus "allwinner-a10", "digic", "fsl,imx25", "fsl,imx31", "xlnx,zynqmp", because they create such CPUs * Assert kvm_enabled(): "host-x86_64-cpu", host-i386-cpu", "host-powerpc64-cpu", "host-embedded-powerpc-cpu", "host-powerpc-cpu" (the powerpc ones can't currently reach the assertion, because the CPUs are only registered when KVM is enabled, but the assertion is arguably in the wrong place all the same) Make qmp_device_list_properties() fail cleanly when the device is so marked. This improves device-list-properties from "crashes, hangs or leaves dangling pointers behind" to "fails". Not a complete fix, just a better-than-nothing work-around. In the above reproducer, device-list-properties now fails with "Can't list properties of device 'pxa2xx-pcmcia'". This also protects -device FOO,help, which uses the same machinery since commit ef52358 "qdev-monitor: include QOM properties in -device FOO, help output", v2.2. Example reproducer: $ qemu-system-aarch64 -machine none -device pxa2xx-pcmcia,help Before: qemu-system-aarch64: .../memory.c:1307: memory_region_finalize: Assertion `((&mr->subregions)->tqh_first == ((void *)0))' failed. After: Can't list properties of device 'pxa2xx-pcmcia' Cc: "Andreas Färber" <afaerber@suse.de> Cc: "Edgar E. Iglesias" <edgar.iglesias@gmail.com> Cc: Alexander Graf <agraf@suse.de> Cc: Anthony Green <green@moxielogic.com> Cc: Aurelien Jarno <aurelien@aurel32.net> Cc: Bastian Koppelmann <kbastian@mail.uni-paderborn.de> Cc: Blue Swirl <blauwirbel@gmail.com> Cc: Eduardo Habkost <ehabkost@redhat.com> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: Jia Liu <proljc@gmail.com> Cc: Leon Alrae <leon.alrae@imgtec.com> Cc: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Michael Walle <michael@walle.cc> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Peter Maydell <peter.maydell@linaro.org> Cc: Richard Henderson <rth@twiddle.net> Cc: qemu-ppc@nongnu.org Cc: qemu-stable@nongnu.org Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eduardo Habkost <ehabkost@redhat.com> Message-Id: <1443689999-12182-10-git-send-email-armbru@redhat.com>
Diffstat (limited to 'target-microblaze/cpu.c')
1 files changed, 6 insertions, 0 deletions
diff --git a/target-microblaze/cpu.c b/target-microblaze/cpu.c
index cbd84a22f7..52959e13b4 100644
--- a/target-microblaze/cpu.c
+++ b/target-microblaze/cpu.c
@@ -264,6 +264,12 @@ static void mb_cpu_class_init(ObjectClass *oc, void *data)
cc->gdb_num_core_regs = 32 + 5;
cc->disas_set_info = mb_disas_set_info;
+ /*
+ * Reason: mb_cpu_initfn() calls cpu_exec_init(), which saves the
+ * object in cpus -> dangling pointer after final object_unref().
+ */
+ dc->cannot_destroy_with_object_finalize_yet = true;
static const TypeInfo mb_cpu_type_info = {