[PATCH] Fix NULL deref in evergreen_cp_wait_vline_sync

[mathieu.berard at crans.org]

From: Mathieu Bérard <mathieu at mberard.eu>

Hello,
a patch for a Xorg segfault triggered here by running rendercheck
with radeon ddx from the evergreen-accel branch

---
 src/evergreen_accel.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/src/evergreen_accel.c b/src/evergreen_accel.c
index d319bc2..38666ee 100644
--- a/src/evergreen_accel.c
+++ b/src/evergreen_accel.c
@@ -242,12 +242,14 @@ void evergreen_cp_wait_vline_sync(ScrnInfoPtr pScrn, PixmapPtr pPix,
 				  xf86CrtcPtr crtc, int start, int stop)
 {
     RADEONInfoPtr  info = RADEONPTR(pScrn);
-    drmmode_crtc_private_ptr drmmode_crtc = crtc->driver_private;
+    drmmode_crtc_private_ptr drmmode_crtc;
     uint32_t offset;
 
     if (!crtc)
         return;
 
+    drmmode_crtc = crtc->driver_private;
+
     if (stop < start)
         return;
 
-- 
1.7.1