Re: [PATCH] i915: don't call drm_atomic_state_put on invalid pointer

From: Chris Wilson <chris@chris-wilson.co.uk>
To: Arnd Bergmann <arnd@arndb.de>
Cc: "Daniel Vetter" <daniel.vetter@intel.com>,
	"Jani Nikula" <jani.nikula@linux.intel.com>,
	"David Airlie" <airlied@linux.ie>,
	"Daniel Vetter" <daniel.vetter@ffwll.ch>,
	"Ville Syrjälä" <ville.syrjala@linux.intel.com>,
	"Maarten Lankhorst" <maarten.lankhorst@linux.intel.com>,
	"Imre Deak" <imre.deak@intel.com>,
	"Ander Conselvan de Oliveira"
	<ander.conselvan.de.oliveira@intel.com>,
	intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] i915: don't call drm_atomic_state_put on invalid pointer
Date: Tue, 18 Oct 2016 16:56:02 +0100	[thread overview]
Message-ID: <20161018155602.GG29358@nuc-i3427.alporthouse.com> (raw)
In-Reply-To: <20161018151652.2690201-1-arnd@arndb.de>

On Tue, Oct 18, 2016 at 05:16:23PM +0200, Arnd Bergmann wrote:
> The introduction of reference counting on the state structures caused
> sanitize_watermarks() in i915 to break in the error handling case,
> as pointed out by gcc -Wmaybe-uninitialized
> 
> drivers/gpu/drm/i915/intel_display.c: In function ‘intel_modeset_init’:
> include/drm/drm_atomic.h:224:2: error: ‘state’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
> 
> This changes the function back to only drop the reference count
> when it was successfully allocated first.
> 
> Fixes: 0853695c3ba4 ("drm: Add reference counting to drm_atomic_state")
> Cc: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Yup, missed that it jumps to fail before allocating state.

Function still looks a bit odd, but nvm
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre