From: Chris Wilson Date: Wed, 28 May 2014 15:16:42 +0000 (+0100) Subject: drm/i915: Check for a NULL shared dpll before dereferencing X-Git-Tag: next-20140604~53^2~21 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=3595a9d59f0a8c729fce83ecab4bf0339a65977c;p=karo-tx-linux.git 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 --- diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 883c69a47a99..0875992c65ed 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);