[PATCH 4/7] drm/amd/powerplay: Zero initialize freq in smu_v11_0_get_current_clk_freq

Nathan Chancellor natechancellor at gmail.com
Thu Jul 4 05:52:15 UTC 2019

clang warns (trimmed for brevity):

drivers/gpu/drm/amd/amdgpu/../powerplay/smu_v11_0.c:1098:10: warning:
variable 'freq' is used uninitialized whenever '?:' condition is false
                ret =  smu_get_current_clk_freq_by_table(smu, clk_id, &freq);

If get_current_clk_freq_by_table is ever NULL, freq will fail to be
properly initialized. Zero initialize it to avoid using uninitialized
stack values.

smu_get_current_clk_freq_by_table expands to a ternary operator
conditional on smu->funcs->get_current_clk_freq_by_table being not NULL.
When this is false, freq will be uninitialized. Zero initialize freq to
avoid using random stack values if that ever happens.

Fixes: e36182490dec ("drm/amd/powerplay: fix dpm freq unit error (10KHz -> Mhz)")
Link: https://github.com/ClangBuiltLinux/linux/issues/585
Signed-off-by: Nathan Chancellor <natechancellor at gmail.com>
 drivers/gpu/drm/amd/powerplay/smu_v11_0.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/powerplay/smu_v11_0.c b/drivers/gpu/drm/amd/powerplay/smu_v11_0.c
index 632a20587c8b..a6f8cd6df7f1 100644
--- a/drivers/gpu/drm/amd/powerplay/smu_v11_0.c
+++ b/drivers/gpu/drm/amd/powerplay/smu_v11_0.c
@@ -1088,7 +1088,7 @@ static int smu_v11_0_get_current_clk_freq(struct smu_context *smu,
 					  uint32_t *value)
 	int ret = 0;
-	uint32_t freq;
+	uint32_t freq = 0;
 	if (clk_id >= SMU_CLK_COUNT || !value)
 		return -EINVAL;

More information about the amd-gfx mailing list