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From: Peter Ujfalusi <peter.ujfalusi@ti.com>
To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: tomi.valkeinen@ti.com, dri-devel@lists.freedesktop.org
Subject: Re: [RFC 1/7] drm/omap: Use devm_kzalloc() to allocate omap_drm_private
Date: Mon, 4 Sep 2017 14:16:32 +0300	[thread overview]
Message-ID: <e1fa01aa-bd4e-3bdf-1253-37d59d1272ec@ti.com> (raw)
In-Reply-To: <1644746.ebjSkL3KDI@avalon>

Hi Laurent,


Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki

On 2017-09-04 12:41, Laurent Pinchart wrote:
> At the moment the memory is freed at .remove() time, which can lead to memory 
> corruption if a user has a handle on the device (for instance an open file 
> handle that is then close()d). Fixing this requires moving memory free to the 
> drm_driver::release() handler. devm_kzalloc() goes in the wrong direction.

Ah, OK, so the current way is buggy as well.

How do you plan to fix that?
I think this should work:

struct omap_drm_private {
	/* First member in the private struct! */
+	struct drm_device ddev;
...
};

Use drm_dev_init(&priv->ddev, ...); to initialize the drm_device instead
of drm_dev_alloc()

then priv->ddev.dev_private = priv;

in this case the drm_dev_unref() would free up our omap_drm_private, right?

I think this is what other DRM drivers are doing, not all, but i915 does
this at least.

But by the description most of the DRM drivers are doing this wrong, right?

- Péter

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  reply	other threads:[~2017-09-04 11:16 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-08-29  7:32 [RFC 0/7] drm/omap: Module parameter for display order configuration Peter Ujfalusi
2017-08-29  7:32 ` [RFC 1/7] drm/omap: Use devm_kzalloc() to allocate omap_drm_private Peter Ujfalusi
2017-09-01 11:10   ` Laurent Pinchart
2017-09-04  9:13     ` Peter Ujfalusi
2017-09-04  9:41       ` Laurent Pinchart
2017-09-04 11:16         ` Peter Ujfalusi [this message]
2017-09-04 14:19           ` Laurent Pinchart
2017-09-05  6:35             ` Peter Ujfalusi
2017-08-29  7:32 ` [RFC 2/7] drm/omap: Allocate drm_device earlier and unref it as last step Peter Ujfalusi
2017-09-01 11:12   ` Laurent Pinchart
2017-08-29  7:32 ` [RFC 3/7] drm/omap: Manage the usable omap_dss_device list within omap_drm_private Peter Ujfalusi
2017-09-01 11:27   ` Laurent Pinchart
2017-09-04  9:19     ` Peter Ujfalusi
2017-09-04  9:45       ` Laurent Pinchart
2017-08-29  7:32 ` [RFC 4/7] drm/omap: Separate the dssdevs array setup from the connect function Peter Ujfalusi
2017-08-29  7:32 ` [RFC 5/7] drm/omap: Do dss_device (display) ordering in omap_drv.c Peter Ujfalusi
2017-09-01 11:32   ` Laurent Pinchart
2017-09-04  9:26     ` Peter Ujfalusi
2017-09-04  9:46       ` Laurent Pinchart
2017-08-29  7:32 ` [RFC 6/7] drm/omap: dss: Remove display ordering from dss/display.c Peter Ujfalusi
2017-08-29  7:32 ` [RFC 7/7] drm/omap: Add kernel parameter to specify the desired display order Peter Ujfalusi
2017-09-01 11:36 ` [RFC 0/7] drm/omap: Module parameter for display order configuration Laurent Pinchart
2017-09-04 10:03   ` Peter Ujfalusi
2018-05-25 20:09     ` Laurent Pinchart
2017-10-05  9:56 ` Pekka Paalanen
2017-10-05 10:01   ` Tomi Valkeinen
2017-10-05 10:43     ` Pekka Paalanen
2017-10-05 11:24       ` Tomi Valkeinen
2017-10-05 11:54         ` Pekka Paalanen

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