[PATCH 5/5] drm/amd/pm: Prevent division by zero

[Denis Arefev]

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: c52dcf49195d ("drm/amd/pp: Avoid divide-by-zero in 
fan_ctrl_set_fan_speed_rpm")
Signed-off-by: Denis Arefev <are...@swemel.ru>
---
 drivers/gpu/drm/amd/pm/powerplay/hwmgr/smu7_thermal.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/amd/pm/powerplay/hwmgr/smu7_thermal.c 
b/drivers/gpu/drm/amd/pm/powerplay/hwmgr/smu7_thermal.c
index a8fc0fa44db6..4182ea06f241 100644
--- a/drivers/gpu/drm/amd/pm/powerplay/hwmgr/smu7_thermal.c
+++ b/drivers/gpu/drm/amd/pm/powerplay/hwmgr/smu7_thermal.c
@@ -266,11 +266,11 @@ int smu7_fan_ctrl_set_fan_speed_rpm(struct pp_hwmgr 
*hwmgr, uint32_t speed)
 
        if (hwmgr->thermal_controller.fanInfo.bNoFan ||
                        (hwmgr->thermal_controller.fanInfo.
-                       ucTachometerPulsesPerRevolution == 0) ||
-                       speed == 0 ||
+                       ucTachometerPulsesPerRevolution == 0) ||
+                       (!speed || speed > UINT_MAX/8) ||
                        (speed < hwmgr->thermal_controller.fanInfo.ulMinRPM) ||
                        (speed > hwmgr->thermal_controller.fanInfo.ulMaxRPM))
-               return 0;
+               return -EINVAL;
 
        if (PP_CAP(PHM_PlatformCaps_MicrocodeFanControl))
                smu7_fan_ctrl_stop_smc_fan_control(hwmgr);
-- 
2.43.0