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From: "simark at simark dot ca" <sourceware-bugzilla@sourceware.org>
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Subject: [Bug gdb/26754] Race condition when resuming threads and one does an
 exec
Date: Thu, 19 Nov 2020 23:55:37 +0000
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https://sourceware.org/bugzilla/show_bug.cgi?id=3D26754

--- Comment #9 from Simon Marchi <simark at simark dot ca> ---
(In reply to Pedro Alves from comment #8)
> >> I would prefer to preserve gdb thread id =3D=3D 1 before / after exec,
> >> but that's a GDB concern, not a kernel interface concern.
> > I don't understand what you mean here.
>=20
> If we delete the zombie leader in reaction to PTRACE_EVENT_EXEC_BEGIN, th=
en
> when we get the PTRACE_EVENT_EXEC, we'll create a new thread for the new
> leader, and that will end up with a GDB tid !=3D 1.
>=20
>    1.1     main ()
>  * 1.2     thread()
>=20
> and after exec we have:
>=20
>  * 1.3     main ()
>=20
> I'm thinking that it would be better to end up with:
>=20
>  * 1.1     main ()
>=20
> Similar to how if a non-threaded program execs, the main thread's thread
> number doesn't change.

Ah yeah of course, we definitely want that behavior.  I don't fully underst=
and
what you say (I would need to go study the code), but it doesn't matter rig=
ht
now, it's all internal GDB bookkeeping.

--=20
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