[PATCH v3 1/3] hw/core/platform-bus: guard platform_bus_get_mmio_addr() against NULL

[Mohammadfaiz Bawa <mbawa@redhat.com>]

sysbus_mmio_get_region() returns NULL when a device has fewer MMIO
regions than the requested slot index.  platform_bus_get_mmio_addr()
passes the result directly to memory_region_is_mapped() without a
NULL check, causing a SIGSEGV.

Return -1 early when the region pointer is NULL, consistent with the
existing "not mapped" path.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Mohammadfaiz Bawa <mbawa@redhat.com>
---
 hw/core/platform-bus.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/hw/core/platform-bus.c b/hw/core/platform-bus.c
index a2217a2dee..16d0ecc0f3 100644
--- a/hw/core/platform-bus.c
+++ b/hw/core/platform-bus.c
@@ -59,8 +59,7 @@ hwaddr platform_bus_get_mmio_addr(PlatformBusDevice *pbus, SysBusDevice *sbdev,
     Object *pbus_mr_obj = OBJECT(pbus_mr);
     Object *parent_mr;
 
-    if (!memory_region_is_mapped(sbdev_mr)) {
-        /* Region is not mapped? */
+    if (!sbdev_mr || !memory_region_is_mapped(sbdev_mr)) {
         return -1;
     }
 
-- 
2.54.0