drm/i915: Check for a NULL shared dpll before dereferencing
This doesn't look possible but a little extra defense against the
improbable is worth it - an oops here could lockup the machine.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index e7e95c3..8635bb7 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -1760,6 +1760,9 @@
struct drm_i915_private *dev_priv = dev->dev_private;
struct intel_shared_dpll *pll = intel_crtc_to_shared_dpll(crtc);
+ if (WARN_ON(pll == NULL))
+ return;
+
WARN_ON(!pll->refcount);
if (pll->active == 0) {
DRM_DEBUG_DRIVER("setting up %s\n", pll->name);
