From be19f0ff482bd5f800d916683784a7e1474d5d6b Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Wed, 28 May 2014 16:16:42 +0100 Subject: [PATCH] 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 Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/intel_display.c | 3 +++ 1 file changed, 3 insertions(+) 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 @@ static void intel_prepare_shared_dpll(struct intel_crtc *crtc) 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); -- 2.7.4