[PATCH][next] drm/amd/pp: don't dereference hwmgr until after it is null checked

From: Colin King
Date: Thu Mar 22 2018 - 19:12:47 EST


From: Colin Ian King <colin.king@xxxxxxxxxxxxx>

Pointer hwmgr is dereferenced before it is null checked, hence there
is a possibility of a null pointer dereference. Fix this by only
dereferencing hwmgr once it is null checked.

Detected by CoverityScan, CID#1466428 ("Dereference before null check")

Fixes: 59156faf810e ("drm/amd/pp: Remove the cgs wrapper for notify smu version on APU")
Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
---
drivers/gpu/drm/amd/powerplay/smumgr/smu8_smumgr.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/powerplay/smumgr/smu8_smumgr.c b/drivers/gpu/drm/amd/powerplay/smumgr/smu8_smumgr.c
index 8c49704b81af..6e88ed67e291 100644
--- a/drivers/gpu/drm/amd/powerplay/smumgr/smu8_smumgr.c
+++ b/drivers/gpu/drm/amd/powerplay/smumgr/smu8_smumgr.c
@@ -698,18 +698,18 @@ static int smu8_start_smu(struct pp_hwmgr *hwmgr)
{
int ret = 0;
uint32_t fw_to_check = 0;
- struct amdgpu_device *adev = hwmgr->adev;
+ struct amdgpu_device *adev;

uint32_t index = SMN_MP1_SRAM_START_ADDR +
SMU8_FIRMWARE_HEADER_LOCATION +
offsetof(struct SMU8_Firmware_Header, Version);

-
if (hwmgr == NULL || hwmgr->device == NULL)
return -EINVAL;

cgs_write_register(hwmgr->device, mmMP0PUB_IND_INDEX, index);
hwmgr->smu_version = cgs_read_register(hwmgr->device, mmMP0PUB_IND_DATA);
+ adev = hwmgr->adev;
adev->pm.fw_version = hwmgr->smu_version >> 8;

fw_to_check = UCODE_ID_RLC_G_MASK |
--
2.15.1