[PATCH v2] drm: Fix object leak in DRM_IOCTL_GEM_CHANGE_HANDLE

[Karol Wachowski <karol.wachowski@linux.intel.com>]

Add missing drm_gem_object_put() call when drm_gem_object_lookup()
successfully returns an object. This fixes a GEM object reference
leak that can prevent driver modules from unloading when using
prime buffers.

Fixes: 53096728b891 ("drm: Add DRM prime interface to reassign GEM handle")
Signed-off-by: Karol Wachowski <karol.wachowski@linux.intel.com>
---
Changes between v1 and v2:
 - move setting ret value under if branch as suggested in review
 - add Cc: stable 6.18+
---
 drivers/gpu/drm/drm_gem.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
index ca1956608261..bcc08a6aebf8 100644
--- a/drivers/gpu/drm/drm_gem.c
+++ b/drivers/gpu/drm/drm_gem.c
@@ -1010,8 +1010,10 @@ int drm_gem_change_handle_ioctl(struct drm_device *dev, void *data,
 	if (!obj)
 		return -ENOENT;
 
-	if (args->handle == args->new_handle)
-		return 0;
+	if (args->handle == args->new_handle) {
+		ret = 0;
+		goto out;
+	}
 
 	mutex_lock(&file_priv->prime.lock);
 
@@ -1043,6 +1045,8 @@ int drm_gem_change_handle_ioctl(struct drm_device *dev, void *data,
 
 out_unlock:
 	mutex_unlock(&file_priv->prime.lock);
+out:
+	drm_gem_object_put(obj);
 
 	return ret;
 }
-- 
2.43.0