drm/radeon: fix possible segfault when parsing pm tables

If we have a empty power table, bail early and allocate
the default power state.

Should fix:
https://bugs.freedesktop.org/show_bug.cgi?id=63865

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org

1 files changed, 9 insertions, 1 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_atombios.c b/drivers/gpu/drm/radeon/radeon_atombios.c
index 0dd87c0e0fac..c4b19f84e6e2 100644
--- a/drivers/gpu/drm/radeon/radeon_atombios.c
+++ b/drivers/gpu/drm/radeon/radeon_atombios.c
@@ -2028,6 +2028,8 @@ static int radeon_atombios_parse_power_table_1_3(struct radeon_device *rdev)
         num_modes = power_info->info.ucNumOfPowerModeEntries;
         if (num_modes > ATOM_MAX_NUMBEROF_POWER_BLOCK)
                 num_modes = ATOM_MAX_NUMBEROF_POWER_BLOCK;
+        if (num_modes == 0)
+                return state_index;
         rdev->pm.power_state = kzalloc(sizeof(struct radeon_power_state) * num_modes, GFP_KERNEL);
         if (!rdev->pm.power_state)
                 return state_index;
@@ -2432,6 +2434,8 @@ static int radeon_atombios_parse_power_table_4_5(struct radeon_device *rdev)
         power_info = (union power_info *)(mode_info->atom_context->bios + data_offset);
 
         radeon_atombios_add_pplib_thermal_controller(rdev, &power_info->pplib.sThermalController);
+        if (power_info->pplib.ucNumStates == 0)
+                return state_index;
         rdev->pm.power_state = kzalloc(sizeof(struct radeon_power_state) *
                                        power_info->pplib.ucNumStates, GFP_KERNEL);
         if (!rdev->pm.power_state)
@@ -2530,6 +2534,8 @@ static int radeon_atombios_parse_power_table_6(struct radeon_device *rdev)
         non_clock_info_array = (struct _NonClockInfoArray *)
                 (mode_info->atom_context->bios + data_offset +
                  le16_to_cpu(power_info->pplib.usNonClockInfoArrayOffset));
+        if (state_array->ucNumEntries == 0)
+                return state_index;
         rdev->pm.power_state = kzalloc(sizeof(struct radeon_power_state) *
                                        state_array->ucNumEntries, GFP_KERNEL);
         if (!rdev->pm.power_state)
@@ -2620,7 +2626,9 @@ void radeon_atombios_get_power_modes(struct radeon_device *rdev)
                 default:
                         break;
                 }
-        } else {
+        }
+
+        if (state_index == 0) {
                 rdev->pm.power_state = kzalloc(sizeof(struct radeon_power_state), GFP_KERNEL);
                 if (rdev->pm.power_state) {
                         rdev->pm.power_state[0].clock_info =