[Qemu-stable] [PATCH for-1.6] target-i386: Fix X86CPU error handling

[Andreas Färber]

Error **errp argument is not for emitting warnings, it means an error
has occurred and the caller should not make any assumptions about the
state of other return values (unless otherwise documented).

Therefore cpu_x86_create() must unref the new X86CPU itself, and
pc_new_cpu() must check for an Error rather than NULL return value.

While at it, clean up a superfluous NULL check.

Reported-by: Jan Kiszka <address@hidden>
Cc: address@hidden
Cc: Igor Mammedov <address@hidden>
Signed-off-by: Andreas Färber <address@hidden>
---
 hw/i386/pc.c      | 13 ++++++-------
 target-i386/cpu.c |  6 +++++-
 2 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index a2b9d88..6a0b042 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -912,20 +912,19 @@ static X86CPU *pc_new_cpu(const char *cpu_model, int64_t 
apic_id,
     X86CPU *cpu;
     Error *local_err = NULL;
 
-    cpu = cpu_x86_create(cpu_model, icc_bridge, errp);
-    if (!cpu) {
-        return cpu;
+    cpu = cpu_x86_create(cpu_model, icc_bridge, &local_err);
+    if (local_err != NULL) {
+        error_propagate(errp, local_err);
+        return NULL;
     }
 
     object_property_set_int(OBJECT(cpu), apic_id, "apic-id", &local_err);
     object_property_set_bool(OBJECT(cpu), true, "realized", &local_err);
 
     if (local_err) {
-        if (cpu != NULL) {
-            object_unref(OBJECT(cpu));
-            cpu = NULL;
-        }
         error_propagate(errp, local_err);
+        object_unref(OBJECT(cpu));
+        cpu = NULL;
     }
     return cpu;
 }
diff --git a/target-i386/cpu.c b/target-i386/cpu.c
index 71ab915..2efbeca 100644
--- a/target-i386/cpu.c
+++ b/target-i386/cpu.c
@@ -1824,7 +1824,11 @@ X86CPU *cpu_x86_create(const char *cpu_model, 
DeviceState *icc_bridge,
     }
 
 out:
-    error_propagate(errp, error);
+    if (error != NULL) {
+        error_propagate(errp, error);
+        object_unref(OBJECT(cpu));
+        cpu = NULL;
+    }
     g_strfreev(model_pieces);
     return cpu;
 }
-- 
1.8.1.4