gpu: nvgpu: fix null access in page table allocation

Check entry->mem.sgt for validity before attempting to dereference it in
a debug print.

Bug 1809939

Change-Id: If7aa7444c162a076d8f23a88dfd2e3e0a9c33813
Signed-off-by: Konsta Holtta <kholtta@nvidia.com>
Reviewed-on: http://git-master/r/1215522
(cherry picked from commit 48c25cd4f1db9d5bb07847af4de29d8f369b52e3)
Reviewed-on: http://git-master/r/1220547
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/mm_gk20a.c b/drivers/gpu/nvgpu/gk20a/mm_gk20a.c
index d66e46b8..bf4a8f57 100644
--- a/drivers/gpu/nvgpu/gk20a/mm_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/mm_gk20a.c
@@ -1292,7 +1292,10 @@ static int gk20a_zalloc_gmmu_page_table(struct vm_gk20a *vm,
 
         err = alloc_gmmu_pages(vm, order, entry);
         gk20a_dbg(gpu_dbg_pte, "entry = 0x%p, addr=%08llx, size %d",
-                  entry, g->ops.mm.get_iova_addr(g, entry->mem.sgt->sgl, 0),
+                  entry,
+                  entry->mem.sgt ?
+                    g->ops.mm.get_iova_addr(g, entry->mem.sgt->sgl, 0)
+                    : 0,
                   order);
         if (err)
                 return err;