Re: [PATCH] Documentation/tracing: Mention that RESET_ATTACK_MITIGATION can clear memory

[Jonathan Corbet]

Steven Rostedt <rostedt@xxxxxxxxxxx> writes:

> On Thu, 26 Sep 2024 19:54:48 +0200
> Hans de Goede <hdegoede@xxxxxxxxxx> wrote:
>
>> Hi,
>> 
>> On 26-Sep-24 7:01 PM, Steven Rostedt wrote:
>> > From: Steven Rostedt <rostedt@xxxxxxxxxxx>
>> > 
>> > At the 2024 Linux Plumbers Conference, I was talking with Hans de Goede
>> > about the persistent buffer to display traces from previous boots. He
>> > mentioned that UEFI can clear memory. In my own tests I have not seen
>> > this. He later informed me that it requires the config option:
>> > 
>> >  CONFIG_RESET_ATTACK_MITIGATION
>> > 
>> > It appears that setting this will allow the memory to be cleared on boot
>> > up, which will definitely clear out the trace of the previous boot.
>> > 
>> > Add this information under the trace_instance in kernel-parameters.txt
>> > to let people know that this can cause issues.
>> > 
>> > Link: https://lore.kernel.org/all/20170825155019.6740-2-ard.biesheuvel@xxxxxxxxxx/
>> > 
>> > Reported-by: Hans de Goede <hdegoede@xxxxxxxxxx>
>> > Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>  
>> 
>> Thanks, patch looks good to me:
>> 
>> Reviewed-by: Hans de Goede <hdegoede@xxxxxxxxxx>
>
> Thanks,
>
> And I forgot to send this to the Documentation maintainers :-p
>
> Jon, could you take this? Do you need me to resend, or can you just pull it
> from lore?

I'll grab it in a bit.

jon