From: Daniel Vetter <daniel@ffwll.ch>
To: Chris Wilson <chris@chris-wilson.co.uk>
Cc: intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH 2/2] drm/i915: Check for a NULL shared dpll before dereferencing
Date: Wed, 28 May 2014 18:14:14 +0200 [thread overview]
Message-ID: <20140528161414.GX14841@phenom.ffwll.local> (raw)
In-Reply-To: <1401290202-21500-2-git-send-email-chris@chris-wilson.co.uk>
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 <chris@chris-wilson.co.uk>
> ---
> 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
prev parent reply other threads:[~2014-05-28 16:14 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-28 15:16 [PATCH 1/2] drm/i915: Silence the WARN if the user tries to GTT mmap an incoherent object Chris Wilson
2014-05-28 15:16 ` [PATCH 2/2] drm/i915: Check for a NULL shared dpll before dereferencing Chris Wilson
2014-05-28 16:14 ` Daniel Vetter [this message]
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