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Commit 32910124 authored by Dan Carpenter's avatar Dan Carpenter Committed by Greg Kroah-Hartman
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staging: greybus: light: fix a couple double frees 



The problem is in gb_lights_request_handler().  If we get a request to
change the config then we release the light with gb_lights_light_release()
and re-allocated it.  However, if the allocation fails part way through
then we call gb_lights_light_release() again.  This can lead to a couple
different double frees where we haven't cleared out the original values:

	gb_lights_light_v4l2_unregister(light);
	...
	kfree(light->channels);
	kfree(light->name);

I also made a small change to how we set "light->channels_count = 0;".
The original code handled this part fine and did not cause a use after
free but it was sort of complicated to read.

Fixes: 2870b52b ("greybus: lights: add lights implementation")
Signed-off-by: default avatarDan Carpenter <dan.carpenter@oracle.com>
Acked-by: default avatarRui Miguel Silva <rmfrfs@gmail.com>
Link: https://lore.kernel.org/r/20190829122839.GA20116@mwanda


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 20738057

drivers/staging/greybus/light.c

+6 −6
Original line number Diff line number Diff line
@@ -1096,21 +1096,21 @@ static void gb_lights_channel_release(struct gb_channel *channel) 
static void gb_lights_light_release(struct gb_light *light)

{

	int i;

	int count;



	light->ready = false;



	count = light->channels_count;



	if (light->has_flash)

		gb_lights_light_v4l2_unregister(light);

	light->has_flash = false;



	for (i = 0; i < count; i++) {

	for (i = 0; i < light->channels_count; i++)

		gb_lights_channel_release(&light->channels[i]);

		light->channels_count--;

	}

	light->channels_count = 0;



	kfree(light->channels);

	light->channels = NULL;

	kfree(light->name);

	light->name = NULL;

}



static void gb_lights_release(struct gb_lights *glights)