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From: Arnd Bergmann <arnd@arndb.de>
To: Jan Kratochvil <jan.kratochvil@redhat.com>
Subject: Re: PPC upstream kernel ignored DABR bug
Date: Wed, 28 Nov 2007 13:28:48 +0100
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Cc: linuxppc-dev@ozlabs.org, Paul Mackerras <paulus@samba.org>,
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On Wednesday 28 November 2007, Jan Kratochvil wrote:
> Please be aware DABR works fine if the same code runs just 1 (always) or
> 2 (sometimes) threads. =C2=A0It starts failing with too many threads runn=
ing:
>=20
> $ ./dabr-lost
> TID 32725: DABR 0x1001279f NIP 0xfecf41c
> TID 32726: DABR 0x1001279f NIP 0xfecf41c
> TID 32725: hitting the variable
> variable found =3D -1, caught TID =3D 32725
> TID 32726: hitting the variable
> variable found =3D -1, caught TID =3D 32726
> The kernel bug did not get reproduced - increase THREADS.
>=20
> As I did not find any code in that kernel touching DABRX its value should=
 not
> be dependent on the number of threads running.
>=20

Right, this is a different problem from the one reported by Uli.
=46rom what I can tell, your problem is that you set the DABR only
in one thread, so the other threads don't see it. DABR is saved
in the thread_struct, so setting it in one thread doesn't have
an impact on any other thread.

	Arnd <><