Messages in this thread Patch in this message | | | Date | Wed, 17 Oct 2018 13:25:21 +0200 | From | Stefan Agner <> | Subject | Re: [PATCH] Revert "drm/imx: don't destroy mode objects manually on driver unbind" |
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On 16.10.2018 18:09, Stefan Agner wrote: > This reverts commit 8e3b16e2117409625b89807de3912ff773aea354. > > Using the component framework requires all components to undo in > ->unbind what ->bind does. Unfortunately that particular commit > broke this rule. In particular, this is an issue if a single > component during probe fails. In that case, component_bind_all() > calls unbind on already succussfully bound components, and then > frees memory allocated using devm. If one of those components > registered e.g. an encoder with the framework then this leads to > use after free situations. > > Revert the commit to ensure that all components properly undo > what ->bind does.
After Lucas comment mentioning HDMI unbind is not proper I looked through all the unbind again. The other unbind functions need some fixing too. I did not bother checking whether those were always broken or just because things changed (the commit this is reverting was in 2016).... Here is what I found:
> > Link: > https://www.mail-archive.com/dri-devel@lists.freedesktop.org/msg233327.html > Suggested-by: Russell King <rmk+kernel@armlinux.org.uk> > Signed-off-by: Stefan Agner <stefan@agner.ch> > --- > drivers/gpu/drm/imx/imx-drm-core.c | 4 ++-- > drivers/gpu/drm/imx/imx-ldb.c | 6 ++++++ > drivers/gpu/drm/imx/imx-tve.c | 3 +++ > drivers/gpu/drm/imx/parallel-display.c | 3 +++ > 4 files changed, 14 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/imx/imx-drm-core.c > b/drivers/gpu/drm/imx/imx-drm-core.c > index 5ea0c82f9957..caa6061a98ba 100644 > --- a/drivers/gpu/drm/imx/imx-drm-core.c > +++ b/drivers/gpu/drm/imx/imx-drm-core.c > @@ -305,11 +305,11 @@ static void imx_drm_unbind(struct device *dev) > > drm_fb_cma_fbdev_fini(drm); > > - drm_mode_config_cleanup(drm); > - > component_unbind_all(drm->dev, drm); > dev_set_drvdata(dev, NULL); > > + drm_mode_config_cleanup(drm); > + > drm_dev_put(drm); > } > > diff --git a/drivers/gpu/drm/imx/imx-ldb.c b/drivers/gpu/drm/imx/imx-ldb.c > index 3bd0f8a18e74..592aabc4a262 100644 > --- a/drivers/gpu/drm/imx/imx-ldb.c > +++ b/drivers/gpu/drm/imx/imx-ldb.c > @@ -723,6 +723,12 @@ static void imx_ldb_unbind(struct device *dev, > struct device *master, > if (channel->panel) > drm_panel_detach(channel->panel); > > + if (!channel->connector.funcs) > + continue; > + > + channel->connector.funcs->destroy(&channel->connector); > + channel->encoder.funcs->destroy(&channel->encoder);
There can be an encoder and bridge, or an encoder and connector. All of them should be properly cleaned up.
So I guess this should look like this:
if (channel->panel) drm_panel_detach(channel->panel);
if (channel->bridge) drm_bridge_detach(channel->bridge); if (channel->connector.funcs) channel->connector.funcs->destroy(&channel->connector); if (channel->encoder.funcs) channel->encoder.funcs->destroy(&channel->encoder); kfree(channel->edid); i2c_put_adapter(channel->ddc);
The last two functions following are only strictly necessary when connector is initialized. But its safe to call them with null, so I would just call them always.
> + > kfree(channel->edid); > i2c_put_adapter(channel->ddc); > } > diff --git a/drivers/gpu/drm/imx/imx-tve.c b/drivers/gpu/drm/imx/imx-tve.c > index cffd3310240e..8d6e89ce1edb 100644 > --- a/drivers/gpu/drm/imx/imx-tve.c > +++ b/drivers/gpu/drm/imx/imx-tve.c > @@ -673,6 +673,9 @@ static void imx_tve_unbind(struct device *dev, > struct device *master, > { > struct imx_tve *tve = dev_get_drvdata(dev); > > + tve->connector.funcs->destroy(&tve->connector); > + tve->encoder.funcs->destroy(&tve->encoder); > +
Cleanup of tve->ddc missing.
> if (!IS_ERR(tve->dac_reg)) > regulator_disable(tve->dac_reg); > } > diff --git a/drivers/gpu/drm/imx/parallel-display.c > b/drivers/gpu/drm/imx/parallel-display.c > index aefd04e18f93..6f11bffcde37 100644 > --- a/drivers/gpu/drm/imx/parallel-display.c > +++ b/drivers/gpu/drm/imx/parallel-display.c > @@ -258,6 +258,9 @@ static void imx_pd_unbind(struct device *dev, > struct device *master, > if (imxpd->panel) > drm_panel_detach(imxpd->panel); >
And in this case a bridge detach is missing.
Will send a v2 with that addressed.
-- Stefan
> + imxpd->encoder.funcs->destroy(&imxpd->encoder); > + imxpd->connector.funcs->destroy(&imxpd->connector); > + > kfree(imxpd->edid); > }
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