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Commit be19f0ff authored by Chris Wilson's avatar Chris Wilson Committed by Daniel Vetter
Browse files

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: default avatarChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent 4328633d

drivers/gpu/drm/i915/intel_display.c

+3 −0
Original line number Original line Diff line number Diff line
@@ -1760,6 +1760,9 @@ static void intel_prepare_shared_dpll(struct intel_crtc *crtc) 
	struct drm_i915_private *dev_priv = dev->dev_private;

	struct drm_i915_private *dev_priv = dev->dev_private;

	struct intel_shared_dpll *pll = intel_crtc_to_shared_dpll(crtc);

	struct intel_shared_dpll *pll = intel_crtc_to_shared_dpll(crtc);





	if (WARN_ON(pll == NULL))

		return;



	WARN_ON(!pll->refcount);

	WARN_ON(!pll->refcount);

	if (pll->active == 0) {

	if (pll->active == 0) {

		DRM_DEBUG_DRIVER("setting up %s\n", pll->name);

		DRM_DEBUG_DRIVER("setting up %s\n", pll->name);