linux-kernel - Re: [PATCH v2 1/6] drm: msm: remove resv fields from msm_gem

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Message-ID: <20190513222547.GA6435@basecamp>
Date:   Mon, 13 May 2019 18:25:47 -0400
From:   Brian Masney <masneyb@...tation.org>
To:     Bjorn Andersson <bjorn.andersson@...aro.org>
Cc:     robdclark@...il.com, sean@...rly.run,
        dri-devel@...ts.freedesktop.org, linux-arm-msm@...r.kernel.org,
        freedreno@...ts.freedesktop.org, airlied@...ux.ie, daniel@...ll.ch,
        linux-kernel@...r.kernel.org, linus.walleij@...aro.org,
        jonathan@...ek.ca, robh@...nel.org
Subject: Re: [PATCH v2 1/6] drm: msm: remove resv fields from msm_gem_object
 struct

On Mon, May 13, 2019 at 01:32:39PM -0700, Bjorn Andersson wrote:
> On Wed 08 May 19:03 PDT 2019, Brian Masney wrote:
> 
> > The msm_gem_object structure contains resv and _resv fields that are
> > no longer needed since the reservation object is now stored on
> > drm_gem_object. msm_atomic_prepare_fb() and msm_atomic_prepare_fb()
> > both referenced the wrong reservation object, and would lead to an
> > attempt to dereference a NULL pointer. Correct those two cases to
> > point to the correct reservation object.
> > 
> > Signed-off-by: Brian Masney <masneyb@...tation.org>
> > Fixes: dd55cf6929e6 ("drm: msm: Switch to use drm_gem_object reservation_object")
> 
> Reviewed-by: Bjorn Andersson <bjorn.andersson@...aro.org>
> Tested-by: Bjorn Andersson <bjorn.andersson@...aro.org>
> 
> This resolves a NULL-pointer dereference about to show up in v5.2-rc1,
> so please pick this up for -rc.

Let me send out another version of just this patch. This snippet below
that I removed needs to stay. I got a little too over eager removing
code.

> > @@ -973,9 +973,6 @@ static int msm_gem_new_impl(struct drm_device *dev,
> >  	msm_obj->flags = flags;
> >  	msm_obj->madv = MSM_MADV_WILLNEED;
> >  
> > -	if (resv)
> > -		msm_obj->base.resv = resv;
> > -
> >  	INIT_LIST_HEAD(&msm_obj->submit_entry);
> >  	INIT_LIST_HEAD(&msm_obj->vmas);
> >  

Brian