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 <[email protected]> Reviewed-by: Eduardo Habkost <[email protected]> Reviewed-by: Michael S. Tsirkin <[email protected]> Signed-off-by: Michael S. Tsirkin <[email protected]>
open-power-host-os · Dec 1, 2017 · 75ba2dd · 75ba2dd
1 parent 758ead3
commit 75ba2dd
Showing 1 changed file with 5 additions and 0 deletions.
diff --git 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) {