[PATCH 21/22] x86: Fix x86_cpu_new() error API violations

[Markus Armbruster]

The Error ** argument must be NULL, &error_abort, &error_fatal, or a
pointer to a variable containing NULL.  Passing an argument of the
latter kind twice without clearing it in between is wrong: if the
first call sets an error, it no longer points to NULL for the second
call.

x86_cpu_new() is wrong that way: it passes &local_err to
object_property_set_uint() without checking it, and then to
qdev_realize().  Harmless, because the former can't actually fail
here.

Fix by checking for failure right away.  While there, replace
qdev_realize(); object_unref() by qdev_realize_and_unref().

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
---
 hw/i386/x86.c | 12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

diff --git a/hw/i386/x86.c b/hw/i386/x86.c
index 34229b45c7..3a7029e6db 100644
--- a/hw/i386/x86.c
+++ b/hw/i386/x86.c
@@ -118,16 +118,10 @@ uint32_t x86_cpu_apic_id_from_index(X86MachineState 
*x86ms,
 
 void x86_cpu_new(X86MachineState *x86ms, int64_t apic_id, Error **errp)
 {
-    Object *cpu = NULL;
-    Error *local_err = NULL;
+    Object *cpu = object_new(MACHINE(x86ms)->cpu_type);
 
-    cpu = object_new(MACHINE(x86ms)->cpu_type);
-
-    object_property_set_uint(cpu, apic_id, "apic-id", &local_err);
-    qdev_realize(DEVICE(cpu), NULL, &local_err);
-
-    object_unref(cpu);
-    error_propagate(errp, local_err);
+    object_property_set_uint(cpu, apic_id, "apic-id", &error_abort);
+    qdev_realize_and_unref(DEVICE(cpu), NULL, errp);
 }
 
 void x86_cpus_init(X86MachineState *x86ms, int default_cpu_version)
-- 
2.26.2