Re: [PATCH][next] drm/amdgpu: fix return of an uninitialized value in variable ret

From: Nathan Chancellor
Date: Fri May 10 2019 - 21:38:33 EST


On Fri, May 10, 2019 at 11:08:42AM +0100, Colin King wrote:
> From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>
> In the case where is_enable is false and lo_base_addr is non-zero the
> variable ret has not been initialized and is being checked for non-zero
> and potentially garbage is being returned. Fix this by not returning
> ret but instead returning -EINVAL on the zero lo_base_addr case.
>
> Addresses-Coverity: ("Uninitialized scalar variable")
> Fixes: a6ac0b44bab9 ("drm/amdgpu: add df perfmon regs and funcs for xgmi")
> Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>

Reviewed-by: Nathan Chancellor <natechancellor@xxxxxxxxx>

This fixes a clang warning complaining about the same thing.

> ---
> drivers/gpu/drm/amd/amdgpu/df_v3_6.c | 5 +----
> 1 file changed, 1 insertion(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/df_v3_6.c b/drivers/gpu/drm/amd/amdgpu/df_v3_6.c
> index a5c3558869fb..8c09bf994acd 100644
> --- a/drivers/gpu/drm/amd/amdgpu/df_v3_6.c
> +++ b/drivers/gpu/drm/amd/amdgpu/df_v3_6.c
> @@ -398,10 +398,7 @@ static int df_v3_6_start_xgmi_link_cntr(struct amdgpu_device *adev,
> NULL);
>
> if (lo_base_addr == 0)
> - ret = -EINVAL;
> -
> - if (ret)
> - return ret;
> + return -EINVAL;
>
> lo_val = RREG32_PCIE(lo_base_addr);
>
> --
> 2.20.1
>