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: c52dcf49195d ("drm/amd/pp: Avoid divide-by-zero in fan_ctrl_set_fan_speed_rpm")
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/powerplay/hwmgr/smu7_thermal.c b/drivers/gpu/drm/amd/pm/powerplay/hwmgr/smu7_thermal.c
index a8fc0fa44db69d0135c714b77bedb549b7036434..ba5c1237fcfe1afe7ade83812705074f4ad7a2db 100644 (file)
--- a/drivers/gpu/drm/amd/pm/powerplay/hwmgr/smu7_thermal.c
+++ b/drivers/gpu/drm/amd/pm/powerplay/hwmgr/smu7_thermal.c
@@ -267,10 +267,10 @@ 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 ||
+                       (!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);