Hi Shuah,
On Fri, Dec 09, 2016 at 09:52:44AM -0700, Shuah Khan wrote:
> Hi Sakari,
>
> I am looking at omap3 isp_remove() closely and I think there are a few
> issues there that could cause problems during unbind.
>
> isp_remove() tries to do media_entity_cleanup() after it unregisters
> media_device
>
> isp_remove() calls isp_unregister_entities() followed by
> isp_cleanup_modules() - cleanup routines call media_entity_cleanup()
>
> media_entity_cleanup() accesses csi2a->subdev.entity which should be gone
> by now after media_device_unregister(). This is just one example. I think
> all of these cleanup routines isp_cleanup_modules() call access subdev.entity.
>
> static void isp_cleanup_modules(struct isp_device *isp)
> {
> omap3isp_h3a_aewb_cleanup(isp);
> omap3isp_h3a_af_cleanup(isp);
> omap3isp_hist_cleanup(isp);
> omap3isp_resizer_cleanup(isp);
> omap3isp_preview_cleanup(isp);
> omap3isp_ccdc_cleanup(isp);
> omap3isp_ccp2_cleanup(isp);
> omap3isp_csi2_cleanup(isp);
> }
>
> This is all done after media_device_cleanup() which does
> ida_destroy(&mdev->entity_internal_idx); and mutex_destroy(&mdev->graph_mutex);
Calling media_entity_cleanup() is not a source of the current problems in
any way. The function is defined in media-entity.h and it does nothing:
static inline void media_entity_cleanup(struct media_entity *entity) {};
We could later discuss when media_entity_cleanup() should be called though.
The existing drivers do call it in their remove() handler.
> I think there are some paths during unbind - isp_remove() that are unsafe.
> I am trying to build https://github.com/gumstix/linux/tree/master now and
> if I can get it to boot - I can send you some logs.
Please do.
--
Kind regards,
Sakari Ailus
e-mail: sakari.ailus@xxxxxx XMPP: sailus@xxxxxxxxxxxxxx
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