There is a window after calling drm_master_release, and before a file is freed, where drm_file can have is_master set to true, but both the drm_file and drm_device have no master. This could result in wrongly approving permissions in drm_is_current_master_locked. Add a check that fpriv->master is non-NULl to guard against this scenario. Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@xxxxxxxxx> --- drivers/gpu/drm/drm_auth.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/drm_auth.c b/drivers/gpu/drm/drm_auth.c index 8c0e0dba1611..f9267b21556e 100644 --- a/drivers/gpu/drm/drm_auth.c +++ b/drivers/gpu/drm/drm_auth.c @@ -66,7 +66,8 @@ static bool drm_is_current_master_locked(struct drm_file *fpriv) lockdep_assert_once(lockdep_is_held(&fpriv->minor->dev->master_lookup_lock) || lockdep_is_held(&fpriv->minor->dev->master_mutex)); - return fpriv->is_master && drm_lease_owner(fpriv->master) == fpriv->minor->dev->master; + return (fpriv->is_master && fpriv->master && + drm_lease_owner(fpriv->master) == fpriv->minor->dev->master); } /** -- 2.25.1
