[PATCH] drm/amd/powerplay: Variable ps could be NULL when it get dereferenced

[Yizhuo]

Inside function cz_get_performance_level(), pointer ps could be NULL via
cast_const_PhwCzPowerState(). However, this pointer is dereferenced
without any check, which is potentially unsafe.

Signed-off-by: Yizhuo <yzhai...@ucr.edu>
---
 drivers/gpu/drm/amd/powerplay/hwmgr/cz_hwmgr.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/amd/powerplay/hwmgr/cz_hwmgr.c 
b/drivers/gpu/drm/amd/powerplay/hwmgr/cz_hwmgr.c
index bc839ff0bdd0..d2628e7b612d 100644
--- a/drivers/gpu/drm/amd/powerplay/hwmgr/cz_hwmgr.c
+++ b/drivers/gpu/drm/amd/powerplay/hwmgr/cz_hwmgr.c
@@ -1799,6 +1799,9 @@ static int cz_get_performance_level(struct pp_hwmgr 
*hwmgr, const struct pp_hw_p
        data = (struct cz_hwmgr *)(hwmgr->backend);
        ps = cast_const_PhwCzPowerState(state);
 
+       if (!ps)
+               return -EINVAL;
+
        level_index = index > ps->level - 1 ? ps->level - 1 : index;
        level->coreClock = ps->levels[level_index].engineClock;
 
-- 
2.17.1