drm/radeon: fix double free

clang static analysis flags this error

drivers/gpu/drm/radeon/ci_dpm.c:5652:9: warning: Use of memory after it is freed [unix.Malloc]
                kfree(rdev->pm.dpm.ps[i].ps_priv);
                      ^~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/radeon/ci_dpm.c:5654:2: warning: Attempt to free released memory [unix.Malloc]
        kfree(rdev->pm.dpm.ps);
        ^~~~~~~~~~~~~~~~~~~~~~

problem is reported in ci_dpm_fini, with these code blocks.

	for (i = 0; i < rdev->pm.dpm.num_ps; i++) {
		kfree(rdev->pm.dpm.ps[i].ps_priv);
	}
	kfree(rdev->pm.dpm.ps);

The first free happens in ci_parse_power_table where it cleans up locally
on a failure.  ci_dpm_fini also does a cleanup.

	ret = ci_parse_power_table(rdev);
	if (ret) {
		ci_dpm_fini(rdev);
		return ret;
	}

So remove the cleanup in ci_parse_power_table and
move the num_ps calculation to inside the loop so ci_dpm_fini
will know how many array elements to free.

Fixes: cc8dbbb4f62a ("drm/radeon: add dpm support for CI dGPUs (v2)")

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

diff --git a/drivers/gpu/drm/radeon/ci_dpm.c b/drivers/gpu/drm/radeon/ci_dpm.c
index 134aa2b..f434efd 100644 (file)
--- a/drivers/gpu/drm/radeon/ci_dpm.c
+++ b/drivers/gpu/drm/radeon/ci_dpm.c
@@ -5563,6 +5563,7 @@ static int ci_parse_power_table(struct radeon_device *rdev)
        if (!rdev->pm.dpm.ps)
                return -ENOMEM;
        power_state_offset = (u8 *)state_array->states;
+       rdev->pm.dpm.num_ps = 0;
        for (i = 0; i < state_array->ucNumEntries; i++) {
                u8 *idx;
                power_state = (union pplib_power_state *)power_state_offset;
@@ -5572,10 +5573,8 @@ static int ci_parse_power_table(struct radeon_device *rdev)
                if (!rdev->pm.power_state[i].clock_info)
                        return -EINVAL;
                ps = kzalloc(sizeof(struct ci_ps), GFP_KERNEL);
-               if (ps == NULL) {
-                       kfree(rdev->pm.dpm.ps);
+               if (ps == NULL)
                        return -ENOMEM;
-               }
                rdev->pm.dpm.ps[i].ps_priv = ps;
                ci_parse_pplib_non_clock_info(rdev, &rdev->pm.dpm.ps[i],
                                              non_clock_info,
@@ -5597,8 +5596,8 @@ static int ci_parse_power_table(struct radeon_device *rdev)
                        k++;
                }
                power_state_offset += 2 + power_state->v2.ucNumDPMLevels;
+               rdev->pm.dpm.num_ps = i + 1;
        }
-       rdev->pm.dpm.num_ps = state_array->ucNumEntries;
 
        /* fill in the vce power states */
        for (i = 0; i < RADEON_MAX_VCE_LEVELS; i++) {