Re: [PATCH] coresight: etm3x: Fix buffer overwrite in cntr_val_show()

[James Clark <james.clark@linaro.org>]

On 26/11/2025 1:42 pm, Mike Leach wrote:
> Hi,
> 
> On Wed, 26 Nov 2025 at 12:31, Leo Yan <leo.yan@arm.com> wrote:
>>
>> On Wed, Nov 26, 2025 at 12:11:05PM +0000, James Clark wrote:
>>
>> [...]
>>
>>>> This fix can still be applied to older kernels, but seems to me that
>>>> now might be an appropriate time to consider removing the ETMv3 driver
>>>> from the mainline kernel?
>>>
>>> Yeah, if anyone is using it it would be on an old kernel surely?
>>
>> We can confirm this in another way: if I don't miss anything, over the
>> past several years (since 2017), we have not received any questions or
>> bug reports based on hands-on practice regarding ETMv3 on the Coresight
>> or perf mailing lists.
>>
>> Thanks,
>> Leo
> 
> The key to this is not the questions we are asked, but which platforms
> are still supported by the linux kernel.
> 
> The ETMv3 driver supports both ETMv3 and PTM trace (the programming
> model is the same, even if the trace decode is vastly different).
> 
> So as long as there are  platforms supported that use either of those,
> we need to keep the driver in.
> 
> Mike
> 

We're not running tests though, so if we find out it's fundamentally 
broken somehow it could be another justification to remove it, even if 
the kernel supports the devices. Do you have a board that you can test 
on Mike?

Maintenance hasn't been zero cost either, even build testing for arm32 
is annoying enough.