drm/radeon: fix race condition UAF in radeon_gem_set_domain_ioctl

From Min Li
1af1cd7be370b08694d8752c97325fe51fdab6aa in linux-6.1.y/6.1.36
982b173a6c6d9472730c3116051977e05d17c8c5 in mainline linux

diff --git a/sys/dev/pci/drm/radeon/radeon_gem.c b/sys/dev/pci/drm/radeon/radeon_gem.c
index 2b87603..f6e6f49 100644 (file)
--- a/sys/dev/pci/drm/radeon/radeon_gem.c
+++ b/sys/dev/pci/drm/radeon/radeon_gem.c
@@ -552,7 +552,6 @@ int radeon_gem_set_domain_ioctl(struct drm_device *dev, void *data,
        struct radeon_device *rdev = dev->dev_private;
        struct drm_radeon_gem_set_domain *args = data;
        struct drm_gem_object *gobj;
-       struct radeon_bo *robj;
        int r;
 
        /* for now if someone requests domain CPU -
@@ -565,13 +564,12 @@ int radeon_gem_set_domain_ioctl(struct drm_device *dev, void *data,
                up_read(&rdev->exclusive_lock);
                return -ENOENT;
        }
-       robj = gem_to_radeon_bo(gobj);
 
        r = radeon_gem_set_domain(gobj, args->read_domains, args->write_domain);
 
        drm_gem_object_put(gobj);
        up_read(&rdev->exclusive_lock);
-       r = radeon_gem_handle_lockup(robj->rdev, r);
+       r = radeon_gem_handle_lockup(rdev, r);
        return r;
 }