From 75ba2ddb188fa07c3442446766782036e3085cba Mon Sep 17 00:00:00 2001 From: Igor Mammedov Date: Mon, 20 Nov 2017 18:19:23 +0100 Subject: [PATCH] pc: fix crash on attempted cpu unplug when qemu is started with '-no-acpi' CLI option, an attempt to unplug a CPU using device_del results in null pointer dereference at: #0 object_get_class #1 pc_machine_device_unplug_request_cb #2 qmp_marshal_device_del which is caused by pcms->acpi_dev == NULL due to ACPI support being disabled. Considering that ACPI support is necessary for unplug to work, check that it's enabled and fail unplug request gracefully if no acpi device were found. Signed-off-by: Igor Mammedov Reviewed-by: Eduardo Habkost Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/i386/pc.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/hw/i386/pc.c b/hw/i386/pc.c index c3afe5b7f156..186545d2a4e5 100644 --- a/hw/i386/pc.c +++ b/hw/i386/pc.c @@ -1842,6 +1842,11 @@ static void pc_cpu_unplug_request_cb(HotplugHandler *hotplug_dev, X86CPU *cpu = X86_CPU(dev); PCMachineState *pcms = PC_MACHINE(hotplug_dev); + if (!pcms->acpi_dev) { + error_setg(&local_err, "CPU hot unplug not supported without ACPI"); + goto out; + } + pc_find_cpu_slot(MACHINE(pcms), cpu->apic_id, &idx); assert(idx != -1); if (idx == 0) {