From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Vetter Subject: Re: [PATCH 2/2] drm/i915: Check for a NULL shared dpll before dereferencing Date: Wed, 28 May 2014 18:14:14 +0200 Message-ID: <20140528161414.GX14841@phenom.ffwll.local> References: <1401290202-21500-1-git-send-email-chris@chris-wilson.co.uk> <1401290202-21500-2-git-send-email-chris@chris-wilson.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail-we0-f176.google.com (mail-we0-f176.google.com [74.125.82.176]) by gabe.freedesktop.org (Postfix) with ESMTP id 64F066E896 for ; Wed, 28 May 2014 09:14:19 -0700 (PDT) Received: by mail-we0-f176.google.com with SMTP id q59so11241468wes.7 for ; Wed, 28 May 2014 09:14:18 -0700 (PDT) Content-Disposition: inline In-Reply-To: <1401290202-21500-2-git-send-email-chris@chris-wilson.co.uk> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" To: Chris Wilson Cc: intel-gfx@lists.freedesktop.org List-Id: intel-gfx@lists.freedesktop.org On Wed, May 28, 2014 at 04:16:42PM +0100, Chris Wilson wrote: > 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 > --- > 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 62fac7e..61fd887 100644 > --- a/drivers/gpu/drm/i915/intel_display.c > +++ b/drivers/gpu/drm/i915/intel_display.c > @@ -1751,6 +1751,9 @@ 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; Yeah, nicely completes our set of WARN checks. Also merged the other patch for sigbus instead of loud WARN to dinq. Thanks, Daniel > + > WARN_ON(!pll->refcount); > if (pll->active == 0) { > DRM_DEBUG_DRIVER("setting up %s\n", pll->name); > -- > 1.7.9.5 > > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/intel-gfx -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch