On 18 May 2017 at 12:49, Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
> 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?
>
Because I think it is part of the review/discussion whether it should
be tagged for stable or not, and it is ultimately up to the maintainer
that applies it whether the tag is added to the patch.
---->8-----
Cc: <stable@xxxxxxxxxxxxxxx>
---->8-----
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