drivers/amd/pm: fix a use-after-free in kv_parse_power_table

When ps allocated by kzalloc equals to NULL, kv_parse_power_table
frees adev->pm.dpm.ps that allocated before. However, after the control
flow goes through the following call chains:

kv_parse_power_table
  |-> kv_dpm_init
        |-> kv_dpm_sw_init
	      |-> kv_dpm_fini

The adev->pm.dpm.ps is used in the for loop of kv_dpm_fini after its
first free in kv_parse_power_table and causes a use-after-free bug.

Fixes: a2e73f56fa62 ("drm/amdgpu: Add support for CIK parts")
Signed-off-by: Zhipeng Lu <alexious@zju.edu.cn>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/pm/legacy-dpm/kv_dpm.c b/drivers/gpu/drm/amd/pm/legacy-dpm/kv_dpm.c
index 5d28c951a319726388c1db65b8200547cd180a9d..5cb4725c773f67a2e2353dc7727a015654c260da 100644 (file)
--- a/drivers/gpu/drm/amd/pm/legacy-dpm/kv_dpm.c
+++ b/drivers/gpu/drm/amd/pm/legacy-dpm/kv_dpm.c
@@ -2735,10 +2735,8 @@ static int kv_parse_power_table(struct amdgpu_device *adev)
                non_clock_info = (struct _ATOM_PPLIB_NONCLOCK_INFO *)
                        &non_clock_info_array->nonClockInfo[non_clock_array_index];
                ps = kzalloc(sizeof(struct kv_ps), GFP_KERNEL);
-               if (ps == NULL) {
-                       kfree(adev->pm.dpm.ps);
+               if (ps == NULL)
                        return -ENOMEM;
-               }
                adev->pm.dpm.ps[i].ps_priv = ps;
                k = 0;
                idx = (u8 *)&power_state->v2.clockInfoIndex[0];