Messages in this thread | | | Date | Tue, 12 Mar 2019 12:00:44 +0100 | From | Daniel Vetter <> | Subject | Re: [PATCH] drm/atomic-helper: Validate pointer before dereference |
| |
On Mon, Mar 11, 2019 at 06:01:20PM -0300, Rodrigo Siqueira wrote: > The function disable_outputs() and > drm_atomic_helper_commit_modeset_enables() tries to retrieve > helper_private from the target CRTC, for dereferencing some operations. > However, the current implementation does not check whether > helper_private is null and, if not, if it has a valid pointer to a dpms > and commit functions. This commit adds pointer validations before > trying to dereference the dpms and commit function. > > Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Please also adjust the kerneldoc for these functions. And I think the patch subject can be improved, e.g. "Make ->atomic_enable/disable crtc callbacks optional". Describe what you're trying to achieve in the summary, not how you achieve it. > --- > drivers/gpu/drm/drm_atomic_helper.c | 30 ++++++++++++++++------------- > 1 file changed, 17 insertions(+), 13 deletions(-) > > diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c > index 540a77a2ade9..fbeef7c461fc 100644 > --- a/drivers/gpu/drm/drm_atomic_helper.c > +++ b/drivers/gpu/drm/drm_atomic_helper.c > @@ -1028,14 +1028,16 @@ disable_outputs(struct drm_device *dev, struct drm_atomic_state *old_state) > > > /* Right function depends upon target state. */ > - if (new_crtc_state->enable && funcs->prepare) > - funcs->prepare(crtc); > - else if (funcs->atomic_disable) > - funcs->atomic_disable(crtc, old_crtc_state); > - else if (funcs->disable) > - funcs->disable(crtc); > - else > - funcs->dpms(crtc, DRM_MODE_DPMS_OFF); > + if (funcs) {
I don't think making funcs optional is a good idea. If you have a crtc with no functions implemented, it's not terribly useful.
Also making functions optional just here is not going to help if we still require it everywhere else. -Daniel
> + if (new_crtc_state->enable && funcs->prepare) > + funcs->prepare(crtc); > + else if (funcs->atomic_disable) > + funcs->atomic_disable(crtc, old_crtc_state); > + else if (funcs->disable) > + funcs->disable(crtc); > + else if (funcs->dpms) > + funcs->dpms(crtc, DRM_MODE_DPMS_OFF); > + } > > if (!(dev->irq_enabled && dev->num_crtcs)) > continue; > @@ -1277,11 +1279,13 @@ void drm_atomic_helper_commit_modeset_enables(struct drm_device *dev, > if (new_crtc_state->enable) { > DRM_DEBUG_ATOMIC("enabling [CRTC:%d:%s]\n", > crtc->base.id, crtc->name); > - > - if (funcs->atomic_enable) > - funcs->atomic_enable(crtc, old_crtc_state); > - else > - funcs->commit(crtc); > + if (funcs) { > + if (funcs->atomic_enable) > + funcs->atomic_enable(crtc, > + old_crtc_state); > + else if (funcs->atomic_enable) > + funcs->commit(crtc); > + } > } > } > > -- > 2.21.0
-- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch
| |