[PATCH] powerpc/legacy_serial: Fix UBSAN: array-index-out-of-bounds

[Michael Ellerman]

Segher Boessenkool <segher at kernel.crashing.org> writes:

> On Sat, May 08, 2021 at 06:36:21AM +0000, Christophe Leroy wrote:
>> UBSAN complains when a pointer is calculated with invalid
>> 'legacy_serial_console' index, allthough the index is verified
>> before dereferencing the pointer.
>
> Addressing like this is UB already.
>
> You could just move this:
>
>> -	if (legacy_serial_console < 0)
>> -		return 0;
>
> to before
>
>> -	struct legacy_serial_info *info = &legacy_serial_infos[legacy_serial_console];
>> -	struct plat_serial8250_port *port = &legacy_serial_ports[legacy_serial_console];
>
> and no other change is necessary.

Yeah I sent a v2 doing that, thanks.

cheers