Re: [PATCH 1/2] input: Add tracepoint support

[WangYuli]

Hi Mathieu,

On 2025/7/23 09:24, Mathieu Desnoyers wrote:
> I've always been worried about adding tracepoint instrumentation of the
> input subsystem that includes the actual keystrokes into the event
> payload. What I'm trying to avoid here is people leaking their password
> by mistake just because they happened to record a trace while
> typing on their keyboard.
The evtest tool can also do this.

However, it doesn't fully report all events from the input subsystem.

From a debugging perspective, adding tracepoints to the input subsystem 
is still more convenient for debugging.

> I don't mind if this gets enabled with a new kernel command line
> options "tracing_leak_my_credentials=yes" or such, but I'd try to
> avoid making it easy to enable by mistake unless this information
> is specifically needed.
I'm not sure if this is over-engineering...

I feel that adding too many command-line parameters will increase the 
user's cognitive load.

However, the leakage of keyboard input records is indeed a very, very 
significant risk.

As a compromise, would it be better if we added a separate Kconfig 
option specifically for the input subsystem's tracepoints to decide 
whether to enable them at compile time, and then documented the 
potential risks within that Kconfig's description?
> But maybe I'm being too careful and people should really learn not
> to share kernel traces with others.
>
> Thoughts ?
Thanks,
--
WangYuli

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