From 07f1c7a7f6736d9ec2eba57d209c5f48888d841e Mon Sep 17 00:00:00 2001 From: Dave Airlie Date: Mon, 20 Apr 2009 09:32:50 +1000 Subject: [PATCH] drm: check for minor master before allowing drop master. When fast user switching a lot eventually we get to the point, where we were checking for the wrong thing in this function. Signed-off-by: Dave Airlie --- drivers/gpu/drm/drm_stub.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/gpu/drm/drm_stub.c b/drivers/gpu/drm/drm_stub.c index 1b3e0ff57b45..ef878615c49f 100644 --- a/drivers/gpu/drm/drm_stub.c +++ b/drivers/gpu/drm/drm_stub.c @@ -185,6 +185,9 @@ int drm_dropmaster_ioctl(struct drm_device *dev, void *data, if (!file_priv->is_master) return -EINVAL; + if (!file_priv->minor->master) + return -EINVAL; + mutex_lock(&dev->struct_mutex); drm_master_put(&file_priv->minor->master); file_priv->is_master = 0;