drm/amd/pm: Prevent division by zero

The user can set any speed value.
If speed is greater than UINT_MAX/8, division by zero is possible.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: c05d1c401572 ("drm/amd/swsmu: add aldebaran smu13 ip support (v3)")
Signed-off-by: Denis Arefev <arefev@swemel.ru>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org

diff --git a/drivers/gpu/drm/amd/pm/swsmu/smu13/smu_v13_0.c b/drivers/gpu/drm/amd/pm/swsmu/smu13/smu_v13_0.c
index 0915d6377613b6d74922a5dba7440d515eca7cd7..ba5a9012dbd5e3e56272c8a00bd1cc77500ec9d0 100644 (file)
--- a/drivers/gpu/drm/amd/pm/swsmu/smu13/smu_v13_0.c
+++ b/drivers/gpu/drm/amd/pm/swsmu/smu13/smu_v13_0.c
@@ -1226,7 +1226,7 @@ int smu_v13_0_set_fan_speed_rpm(struct smu_context *smu,
        uint32_t tach_period;
        int ret;
 
-       if (!speed)
+       if (!speed || speed > UINT_MAX/8)
                return -EINVAL;
 
        ret = smu_v13_0_auto_fan_control(smu, 0);