[PATCH] drm: Take mode_config.mutex in setcrtc ioctl

[Daniel Vetter]

On Thu, Apr 06, 2017 at 03:09:04PM -0400, Alex Deucher wrote:
> On Thu, Apr 6, 2017 at 3:06 PM, Daniel Vetter <daniel.vetter at ffwll.ch> wrote:
> > Legacy drivers insist that we really take all the locks in this path,
> > and the harm in doing so is minimal.
> >
> > v2: Like git add, it exists :(
> >
> > Fixes: 2ceb585a956c ("drm: Add explicit acquire ctx handling around ->set_config")
> > Cc: Harry Wentland <harry.wentland at amd.com>
> > Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> > Cc: Daniel Vetter <daniel.vetter at intel.com>
> > Cc: Jani Nikula <jani.nikula at linux.intel.com>
> > Cc: Sean Paul <seanpaul at chromium.org>
> > Cc: David Airlie <airlied at linux.ie>
> > Cc: dri-devel at lists.freedesktop.org
> > Cc: Alex Deucher <alexdeucher at gmail.com>
> > Reported-by: Alex Deucher <alexdeucher at gmail.com>
> > Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
> 
> This actually matches what I tested locally.
> 
> Acked-and-tested-by: Alex Deucher <alexander.deucher at amd.com>

Thanks for quickly testing this, applied.
-Daniel

> 
> > ---
> >  drivers/gpu/drm/drm_crtc.c | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
> > index d69e180fc563..5af25ce5bf7c 100644
> > --- a/drivers/gpu/drm/drm_crtc.c
> > +++ b/drivers/gpu/drm/drm_crtc.c
> > @@ -576,6 +576,7 @@ int drm_mode_setcrtc(struct drm_device *dev, void *data,
> >         }
> >         DRM_DEBUG_KMS("[CRTC:%d:%s]\n", crtc->base.id, crtc->name);
> >
> > +       mutex_lock(&crtc->dev->mode_config.mutex);
> >         drm_modeset_acquire_init(&ctx, 0);
> >  retry:
> >         ret = drm_modeset_lock_all_ctx(crtc->dev, &ctx);
> > @@ -721,6 +722,7 @@ int drm_mode_setcrtc(struct drm_device *dev, void *data,
> >         }
> >         drm_modeset_drop_locks(&ctx);
> >         drm_modeset_acquire_fini(&ctx);
> > +       mutex_unlock(&crtc->dev->mode_config.mutex);
> >
> >         return ret;
> >  }
> > --
> > 2.11.0
> >

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