From: Dave Airlie <airlied@redhat.com>
Date: Sun, 19 Apr 2009 23:32:50 +0000 (+1000)
Subject: drm: check for minor master before allowing drop master.
X-Git-Tag: MMI-PSA29.97-13-9~28229^2~8
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=07f1c7a7f6736d9ec2eba57d209c5f48888d841e;p=GitHub%2FMotorolaMobilityLLC%2Fkernel-slsi.git

drm: check for minor master before allowing drop 

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 <airlied@redhat.com>
---

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;