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Commit 7751f609 authored by Dan Carpenter's avatar Dan Carpenter Committed by Greg Kroah-Hartman
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mcb: fix error handling in mcb_alloc_bus() 



commit 25a1433216489de4abc889910f744e952cb6dbae upstream.

There are two bugs:
1) If ida_simple_get() fails then this code calls put_device(carrier)
   but we haven't yet called get_device(carrier) and probably that
   leads to a use after free.
2) After device_initialize() then we need to use put_device() to
   release the bus.  This will free the internal resources tied to the
   device and call mcb_free_bus() which will free the rest.

Fixes: 5d9e2ab9 ("mcb: Implement bus->dev.release callback")
Fixes: 18d28819 ("mcb: Correctly initialize the bus's device")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: default avatarJohannes Thumshirn <jth@kernel.org>
Link: https://lore.kernel.org/r/32e160cf6864ce77f9d62948338e24db9fd8ead9.1630931319.git.johannes.thumshirn@wdc.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 406ff5bf

drivers/mcb/mcb-core.c

+6 −6
Original line number Diff line number Diff line
@@ -277,8 +277,8 @@ struct mcb_bus *mcb_alloc_bus(struct device *carrier) 


	bus_nr = ida_simple_get(&mcb_ida, 0, 0, GFP_KERNEL);

	if (bus_nr < 0) {

		rc = bus_nr;

		goto err_free;

		kfree(bus);

		return ERR_PTR(bus_nr);

	}



	bus->bus_nr = bus_nr;
@@ -293,12 +293,12 @@ struct mcb_bus *mcb_alloc_bus(struct device *carrier) 
	dev_set_name(&bus->dev, "mcb:%d", bus_nr);

	rc = device_add(&bus->dev);

	if (rc)

		goto err_free;

		goto err_put;



	return bus;

err_free:

	put_device(carrier);

	kfree(bus);



err_put:

	put_device(&bus->dev);

	return ERR_PTR(rc);

}

EXPORT_SYMBOL_GPL(mcb_alloc_bus);