From 8d5b80b1aff0e6eacc317ba23a98beb9500e7319 Mon Sep 17 00:00:00 2001 From: Tuo Li Date: Thu, 21 Oct 2021 21:04:48 +0800 Subject: [PATCH] gpu: drm: amd: amdgpu: amdgpu_i2c: fix possible uninitialized-variable access in amdgpu_i2c_router_select_ddc_port() stable inclusion from stable-5.10.67 commit 2254383788ff93a423e20068333b9f8376d56cb4 bugzilla: 182619 https://gitee.com/openeuler/kernel/issues/I4EWO7 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=2254383788ff93a423e20068333b9f8376d56cb4 -------------------------------- [ 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 Signed-off-by: Tuo Li Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin Signed-off-by: Chen Jun Acked-by: Weilong Chen Signed-off-by: Chen Jun Signed-off-by: Zheng Zengkai --- 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 47cad23a6b9e..b91d3d29b410 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_i2c.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_i2c.c @@ -339,7 +339,7 @@ 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; -- GitLab