| From fa4df3cf13ca02c80eec82a74e3082489567eab6 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Wed, 11 Aug 2021 04:34:58 -0700 |
| Subject: gpu: drm: amd: amdgpu: amdgpu_i2c: fix possible |
| uninitialized-variable access in amdgpu_i2c_router_select_ddc_port() |
| |
| From: Tuo Li <islituo@gmail.com> |
| |
| [ Upstream commit a211260c34cfadc6068fece8c9e99e0fe1e2a2b6 ] |
| |
| The variable val is declared without initialization, and its address is |
| passed to amdgpu_i2c_get_byte(). In this function, the value of val is |
| accessed in: |
| DRM_DEBUG("i2c 0x%02x 0x%02x read failed\n", |
| addr, *val); |
| |
| Also, when amdgpu_i2c_get_byte() returns, val may remain uninitialized, |
| but it is accessed in: |
| val &= ~amdgpu_connector->router.ddc_mux_control_pin; |
| |
| To fix this possible uninitialized-variable access, initialize val to 0 in |
| amdgpu_i2c_router_select_ddc_port(). |
| |
| Reported-by: TOTE Robot <oslab@tsinghua.edu.cn> |
| Signed-off-by: Tuo Li <islituo@gmail.com> |
| Signed-off-by: Alex Deucher <alexander.deucher@amd.com> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| drivers/gpu/drm/amd/amdgpu/amdgpu_i2c.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_i2c.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_i2c.c |
| index f2739995c335..199eccee0b0b 100644 |
| --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_i2c.c |
| +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_i2c.c |
| @@ -338,7 +338,7 @@ static void amdgpu_i2c_put_byte(struct amdgpu_i2c_chan *i2c_bus, |
| void |
| amdgpu_i2c_router_select_ddc_port(const struct amdgpu_connector *amdgpu_connector) |
| { |
| - u8 val; |
| + u8 val = 0; |
| |
| if (!amdgpu_connector->router.ddc_valid) |
| return; |
| -- |
| 2.30.2 |
| |
