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Message-ID: <CAGngYiWHe1mw0+Ay6HO7kG5y8HMriUX3BO8VUcTvGayEK-4JOw@mail.gmail.com>
Date: Thu, 19 Sep 2019 10:28:22 -0400
From: Sven Van Asbroeck <thesven73@...il.com>
To: "Koenig, Christian" <Christian.Koenig@....com>
Cc: Navid Emamdoost <navid.emamdoost@...il.com>,
"emamd001@....edu" <emamd001@....edu>,
"smccaman@....edu" <smccaman@....edu>,
"kjlu@....edu" <kjlu@....edu>,
"Deucher, Alexander" <Alexander.Deucher@....com>,
"Zhou, David(ChunMing)" <David1.Zhou@....com>,
David Airlie <airlied@...ux.ie>,
Daniel Vetter <daniel@...ll.ch>, Rex Zhu <Rex.Zhu@....com>,
Sam Ravnborg <sam@...nborg.org>,
"amd-gfx@...ts.freedesktop.org" <amd-gfx@...ts.freedesktop.org>,
"dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] drm/amdgpu: fix multiple memory leaks
Hi Christian,
On Thu, Sep 19, 2019 at 4:05 AM Koenig, Christian
<Christian.Koenig@....com> wrote:
>
> > +out4:
> > + kfree(i2s_pdata);
> > +out3:
> > + kfree(adev->acp.acp_res);
> > +out2:
> > + kfree(adev->acp.acp_cell);
> > +out1:
> > + kfree(adev->acp.acp_genpd);
>
> kfree on a NULL pointer is harmless, so a single error label should be
> sufficient.
That is true, but I notice that the adev structure comes from outside this
driver:
static int acp_hw_init(void *handle)
{
...
struct amdgpu_device *adev = (struct amdgpu_device *)handle;
...
}
As far as I can tell, the init() does not explicitly set these to NULL:
adev->acp.acp_res
adev->acp.acp_cell
adev->acp.acp_genpd
I am assuming that core code sets these to NULL, before calling
acp_hw_init(). But is that guaranteed or simply a happy accident?
Ie. if they are NULL today, are they likely to remain NULL tomorrow?
Because calling kfree() on a stale pointer would be, well
not good. Especially not on an error path, which typically
does not receive much testing, if any.
My apologies if I have misinterpreted this, I am not familiar with
this code base.
Sven
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