linux-kernel - Re: [PATCH] drm/amdgpu: don't add files at control minor debugfs directory

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Message-ID: <20161206071759.2yoiebqrmhckrlfz@phenom.ffwll.local>
Date:   Tue, 6 Dec 2016 08:17:59 +0100
From:   Daniel Vetter <daniel@...ll.ch>
To:     Mike Lothian <mike@...eburn.co.uk>
Cc:     "Deucher, Alexander" <Alexander.Deucher@....com>,
        Nicolai Stange <nicstange@...il.com>,
        Daniel Vetter <daniel.vetter@...el.com>,
        Michel Dänzer <michel@...nzer.net>,
        "Koenig, Christian" <Christian.Koenig@....com>,
        "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] drm/amdgpu: don't add files at control minor debugfs
 directory

On Tue, Dec 06, 2016 at 02:01:37AM +0000, Mike Lothian wrote:
> Feel free to add a tested by from myself
> 
> Thanks for the fix
> 
> On Mon, 5 Dec 2016 at 20:33 Deucher, Alexander <Alexander.Deucher@....com>
> wrote:
> 
> > > -----Original Message-----
> > > From: Nicolai Stange [mailto:nicstange@...il.com]
> > > Sent: Monday, December 05, 2016 3:30 PM
> > > To: Daniel Vetter
> > > Cc: Deucher, Alexander; Koenig, Christian; Michel Dänzer; linux-
> > > kernel@...r.kernel.org; dri-devel@...ts.freedesktop.org; Nicolai Stange
> > > Subject: [PATCH] drm/amdgpu: don't add files at control minor debugfs
> > > directory
> > >
> > > Since commit 8a357d10043c ("drm: Nerf DRM_CONTROL nodes"), a
> > > struct drm_device's ->control member is always NULL.
> > >
> > > In the case of CONFIG_DEBUG_FS=y, amdgpu_debugfs_add_files() accesses
> > > ->control->debugfs_root though. This results in a NULL pointer
> > > dereference.
> > >
> > > Fix this by omitting the drm_debugfs_create_files() call for the
> > > control minor debugfs directory which is now non-existent anyway.
> > >
> > > Fixes: 8a357d10043c ("drm: Nerf DRM_CONTROL nodes")
> > > Signed-off-by: Nicolai Stange <nicstange@...il.com>
> >
> > Please add the bugzilla:
> > https://bugs.freedesktop.org/show_bug.cgi?id=98915
> > With that,
> > Reviewed-by: Alex Deucher <alexander.deucher@....com>

Applied to drm-misc, thanks for catching this and sorry for the fallout I
caused.
-Daniel

> >
> > > ---
> > > Applicable to next-20161202. Compile-only tested.
> > >
> > >  drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 6 ------
> > >  1 file changed, 6 deletions(-)
> > >
> > > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> > > b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> > > index deee2db..0cb3e82 100644
> > > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> > > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> > > @@ -2493,9 +2493,6 @@ int amdgpu_debugfs_add_files(struct
> > > amdgpu_device *adev,
> > >       adev->debugfs_count = i;
> > >  #if defined(CONFIG_DEBUG_FS)
> > >       drm_debugfs_create_files(files, nfiles,
> > > -                              adev->ddev->control->debugfs_root,
> > > -                              adev->ddev->control);
> > > -     drm_debugfs_create_files(files, nfiles,
> > >                                adev->ddev->primary->debugfs_root,
> > >                                adev->ddev->primary);
> > >  #endif
> > > @@ -2510,9 +2507,6 @@ static void amdgpu_debugfs_remove_files(struct
> > > amdgpu_device *adev)
> > >       for (i = 0; i < adev->debugfs_count; i++) {
> > >               drm_debugfs_remove_files(adev->debugfs[i].files,
> > >                                        adev->debugfs[i].num_files,
> > > -                                      adev->ddev->control);
> > > -             drm_debugfs_remove_files(adev->debugfs[i].files,
> > > -                                      adev->debugfs[i].num_files,
> > >                                        adev->ddev->primary);
> > >       }
> > >  #endif
> > > --
> > > 2.10.2
> >
> > _______________________________________________
> > dri-devel mailing list
> > dri-devel@...ts.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/dri-devel
> >

> _______________________________________________
> dri-devel mailing list
> dri-devel@...ts.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel


-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

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