arm psci_probe() bug

[Sascha Hauer]

Hi Alexander,

On Thu, Aug 03, 2023 at 11:04:36AM +0300, Alexander Shiyan wrote:
> Hello.
> 
> I found a bug in psci processing.
> Currently the kernel writes the following on boot:
> psci: probing for conduit method from DT.
> psci: invalid "method" property:
> ...
> 
> In the psci_probe() function we do the following:
> ret = of_property_read_string(dev->of_node, "method", &method);
> and use this (method) variable as an argument for of_psci_fixup().
> I suspect we are free this variable at of_property_write_string ->
> of_set_property > of_delete_property.
> 
> Can you confirm my thought and correct it in the right direction?

Are you using the internal device tree for booting? If yes, then I think
this can happen. As I just saw when booting with the internal device
tree then of_get_fixed_tree() is called with the barebox live tree as
argument. We shouldn't do this and use a copy instead.

Nevertheless I think we shouldn't assume the string returned from
of_property_read_string() is valid for all eternity and make a copy
there as well.

Sascha


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