[PATCH] nbio_v7_4: Add pointer check

[Denis Arefev]

Return value of a function 'amdgpu_ras_find_obj' is dereferenced 
at nbio_v7_4.c:325 without checking for null

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Signed-off-by: Denis Arefev <arefev at swemel.ru>
---
 drivers/gpu/drm/amd/amdgpu/nbio_v7_4.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/nbio_v7_4.c b/drivers/gpu/drm/amd/amdgpu/nbio_v7_4.c
index eadc9526d33f..0f2ac99de864 100644
--- a/drivers/gpu/drm/amd/amdgpu/nbio_v7_4.c
+++ b/drivers/gpu/drm/amd/amdgpu/nbio_v7_4.c
@@ -304,6 +304,9 @@ static void nbio_v7_4_handle_ras_controller_intr_no_bifring(struct amdgpu_device
 	struct ras_err_data err_data = {0, 0, 0, NULL};
 	struct amdgpu_ras *ras = amdgpu_ras_get_context(adev);
 
+	if (!obj)
+	  return;
 
 	bif_doorbell_intr_cntl = RREG32_SOC15(NBIO, 0, mmBIF_DOORBELL_INT_CNTL);
 	if (REG_GET_FIELD(bif_doorbell_intr_cntl,
 		BIF_DOORBELL_INT_CNTL, RAS_CNTLR_INTERRUPT_STATUS)) {
-- 
2.25.1