On Thu, May 18, 2017 at 12:29:55PM +0100, Ard Biesheuvel wrote:
> Commit fa01e2ca9f53 ("serial: 8250: Integrate Fintek into 8250_base")
> modified the probing logic for PNP0501 devices, to remove a collision
> between the generic 16550A driver and the Fintek driver, which reused
> the same ACPI _HID.
>
> The Fintek device probe is now incorporated into the common 8250 probe
> path, and gets called for all discovered 16550A compatible devices,
> including ones that are MMIO mapped rather than IO mapped. However,
> the Fintek driver assumes the port base is a I/O address, and proceeds
> to probe some arbitrary offsets above it.
>
> This is generally a wrong thing to do, but on ARM systems (having no
> native port I/O), this may result in faulting accesses of completely
> unrelated MMIO regions in the PCI I/O space. Given that this is at
> serial probe time, this results in hard to diagnose crashes at boot.
>
> So let's restrict the Fintek probe to devices that we know are using
> port I/O in the first place.
>
> Fixes: fa01e2ca9f53 ("serial: 8250: Integrate Fintek into 8250_base")
> Suggested-by: Arnd Bergmann <arnd@xxxxxxxx>
> Reviewed-by: Ricardo Ribalda <ricardo.ribalda@xxxxxxxxx>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
> ---
> Resending with Ricardo's ack added.
>
> Could we please tag this for -stable? Thanks.
You could have done that in the patch itself, why have me manually add
it?
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