[PATCH v3 1/6] pc: fix possible NULL pointer dereference in pc_machine_get_device_memory_region_size()

[Igor Mammedov <imammedo@xxxxxxxxxx>]

QEMU will crash when device-memory-region-size property is read if ms->device_memory
wasn't initialized yet (ex: property being inspected during preconfig time).

Instead of crashing return 0 if ms->device_memory hasn't been initialized.

Signed-off-by: Igor Mammedov <imammedo@xxxxxxxxxx>
---
 hw/i386/pc.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index d98b737..de91e90 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -2461,7 +2461,11 @@ pc_machine_get_device_memory_region_size(Object *obj, Visitor *v,
                                          Error **errp)
 {
     MachineState *ms = MACHINE(obj);
-    int64_t value = memory_region_size(&ms->device_memory->mr);
+    int64_t value = 0;
+
+    if (ms->device_memory) {
+        memory_region_size(&ms->device_memory->mr);
+    }
 
     visit_type_int(v, name, &value, errp);
 }
-- 
2.7.4

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