Re: [PATCH] drm/self_refresh: Fix possible NULL deref in failure path

From: Sean Paul <sean@poorly.run>
To: Daniel Vetter <daniel@ffwll.ch>
Cc: Zain Wang <wzz@rock-chips.com>,
	Maxime Ripard <maxime.ripard@bootlin.com>,
	Sam Ravnborg <sam@ravnborg.org>,
	Jose Souza <jose.souza@intel.com>,
	Tomasz Figa <tfiga@chromium.org>, David Airlie <airlied@linux.ie>,
	Sean Paul <seanpaul@chromium.org>,
	dri-devel@lists.freedesktop.org,
	Dan Carpenter <dan.carpenter@oracle.com>,
	Sean Paul <sean@poorly.run>
Subject: Re: [PATCH] drm/self_refresh: Fix possible NULL deref in failure path
Date: Thu, 20 Jun 2019 10:47:41 -0400	[thread overview]
Message-ID: <20190620144741.GH25413@art_vandelay> (raw)
In-Reply-To: <20190620112855.GQ12905@phenom.ffwll.local>

On Thu, Jun 20, 2019 at 01:28:55PM +0200, Daniel Vetter wrote:
> On Wed, Jun 19, 2019 at 02:19:47PM -0400, Sean Paul wrote:
> > From: Sean Paul <seanpaul@chromium.org>
> > 
> > If state allocation fails, we still try to give back the reference on
> > it. Also initialize ret in case the crtc is not enabled and we hit the
> > eject button.
> > 
> > Fixes: 1452c25b0e60 ("drm: Add helpers to kick off self refresh mode in drivers")
> > Cc: Daniel Vetter <daniel@ffwll.ch>
> > Cc: Jose Souza <jose.souza@intel.com>
> > Cc: Zain Wang <wzz@rock-chips.com>
> > Cc: Tomasz Figa <tfiga@chromium.org>
> > Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > Cc: Sam Ravnborg <sam@ravnborg.org>
> > Cc: Sean Paul <seanpaul@chromium.org>
> > Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> > Cc: Maxime Ripard <maxime.ripard@bootlin.com>
> > Cc: Sean Paul <sean@poorly.run>
> > Cc: David Airlie <airlied@linux.ie>
> > Cc: dri-devel@lists.freedesktop.org
> > Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> > Signed-off-by: Sean Paul <seanpaul@chromium.org>
> 
> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> 

Applied to -misc-next, thanks!

Sean

> > ---
> >  drivers/gpu/drm/drm_self_refresh_helper.c | 6 ++++--
> >  1 file changed, 4 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/drm_self_refresh_helper.c b/drivers/gpu/drm/drm_self_refresh_helper.c
> > index e0d2ad1f070cb..4b9424a8f1f1c 100644
> > --- a/drivers/gpu/drm/drm_self_refresh_helper.c
> > +++ b/drivers/gpu/drm/drm_self_refresh_helper.c
> > @@ -69,14 +69,14 @@ static void drm_self_refresh_helper_entry_work(struct work_struct *work)
> >  	struct drm_connector *conn;
> >  	struct drm_connector_state *conn_state;
> >  	struct drm_crtc_state *crtc_state;
> > -	int i, ret;
> > +	int i, ret = 0;
> >  
> >  	drm_modeset_acquire_init(&ctx, 0);
> >  
> >  	state = drm_atomic_state_alloc(dev);
> >  	if (!state) {
> >  		ret = -ENOMEM;
> > -		goto out;
> > +		goto out_drop_locks;
> >  	}
> >  
> >  retry:
> > @@ -116,6 +116,8 @@ static void drm_self_refresh_helper_entry_work(struct work_struct *work)
> >  	}
> >  
> >  	drm_atomic_state_put(state);
> > +
> > +out_drop_locks:
> >  	drm_modeset_drop_locks(&ctx);
> >  	drm_modeset_acquire_fini(&ctx);
> >  }
> > -- 
> > Sean Paul, Software Engineer, Google / Chromium OS
> > 
> 
> -- 
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch

-- 
Sean Paul, Software Engineer, Google / Chromium OS
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