drm/mgag200: fix null pointer dereference

we are referencing the pointer after doing alloc_apertures,
as alloc_apertures kzallocs, the kzalloc may fail and we get a NULL.

so we need to check for NULL before we dereference this pointer

Signed-off-by: Devendra Naga <devendra.aaru@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

diff --git a/drivers/gpu/drm/mgag200/mgag200_drv.c b/drivers/gpu/drm/mgag200/mgag200_drv.c
index 93e832d..ea1024d 100644 (file)
--- a/drivers/gpu/drm/mgag200/mgag200_drv.c
+++ b/drivers/gpu/drm/mgag200/mgag200_drv.c
@@ -47,6 +47,9 @@ static void mgag200_kick_out_firmware_fb(struct pci_dev *pdev)
        bool primary = false;
 
        ap = alloc_apertures(1);
+       if (!ap)
+               return;
+
        ap->ranges[0].base = pci_resource_start(pdev, 0);
        ap->ranges[0].size = pci_resource_len(pdev, 0);