[LTP] [PATCH v6 1/1] thp04: Add ptrace mode and fix tracee stop synchronization

[Jan Polensky]

On Fri, Jul 10, 2026 at 01:26:27PM +0200, Cyril Hrubis wrote:
> Hi!
> > - Note: Serialization eliminates the race; tests write functionality
>
> I'm a bit puzzled by this line. If there is no chance of hitting the
> race wouldn't it make much more sense to write a separate ptrace test
> that would excercise the parent being able to write into child memory?
>
> --
> Cyril Hrubis
> chrubis@suse.cz
Hi Cyril,

That's a fair point.

The main goal was to keep thp04 functional on kernels with
CONFIG_PROC_MEM_FORCE_PTRACE=y, where direct writes via /proc/self/mem
are no longer possible.

Do you have a preference for how support for that configuration should
look?

Would you prefer:

  1. Keeping thp04 focused on the original race test and skipping it
     when only ptrace-based writes are available?

  2. Splitting the ptrace write validation into a separate testcase and
     leaving thp04 unchanged?

  3. Some other approach?

I'm mostly trying to understand the intended coverage for
CONFIG_PROC_MEM_FORCE_PTRACE=y before making further changes.

Thanks,
Jan