From: Michael Ellerman <mpe@ellerman.id.au>
To: Christophe Leroy <christophe.leroy@csgroup.eu>,
Timothy Pearson <tpearson@raptorengineering.com>
Cc: Jens Axboe <axboe@kernel.dk>,
regressions <regressions@lists.linux.dev>,
npiggin <npiggin@gmail.com>,
linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Subject: Re: [PATCH v2] powerpc: Don't clobber fr0/vs0 during fp|altivec register save
Date: Tue, 28 Nov 2023 11:59:35 +1100 [thread overview]
Message-ID: <871qca4rrc.fsf@mail.lhotse> (raw)
In-Reply-To: <89de310e-bb9a-4485-bc8c-3fbefc90e6f6@csgroup.eu>
Christophe Leroy <christophe.leroy@csgroup.eu> writes:
> Le 27/11/2023 à 19:39, Timothy Pearson a écrit :
>> Just wanted to check back and see if this patch was going to be
>> queued up soon? We're still having to work around / advertise the
>> data destruction issues the underlying bug is causing on e.g. Debian
>> Stable.
>
> Has any agreement been reach on the final solution ? Seeing the many
> discussion on patch v2 I had the feeling that it was not the final solution.
The actual patch is fine I think.
The discussion was about improving the explanation of exactly what's
happening in the change log, and whether there is a larger bug causing
FP corruption unrelated to io-uring.
I'm now reasonably confident there's no detectable corruption of fr0
happening except via the io-uring -> clone path.
It's still a bad bug for us to corrupt fr0 across sys_clone(), but in
practice it doesn't affect userspace because fr0 is volatile across
function calls.
cheers
WARNING: multiple messages have this Message-ID (diff)
From: Michael Ellerman <mpe@ellerman.id.au>
To: Christophe Leroy <christophe.leroy@csgroup.eu>,
Timothy Pearson <tpearson@raptorengineering.com>
Cc: Jens Axboe <axboe@kernel.dk>,
linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
regressions <regressions@lists.linux.dev>,
npiggin <npiggin@gmail.com>
Subject: Re: [PATCH v2] powerpc: Don't clobber fr0/vs0 during fp|altivec register save
Date: Tue, 28 Nov 2023 11:59:35 +1100 [thread overview]
Message-ID: <871qca4rrc.fsf@mail.lhotse> (raw)
In-Reply-To: <89de310e-bb9a-4485-bc8c-3fbefc90e6f6@csgroup.eu>
Christophe Leroy <christophe.leroy@csgroup.eu> writes:
> Le 27/11/2023 à 19:39, Timothy Pearson a écrit :
>> Just wanted to check back and see if this patch was going to be
>> queued up soon? We're still having to work around / advertise the
>> data destruction issues the underlying bug is causing on e.g. Debian
>> Stable.
>
> Has any agreement been reach on the final solution ? Seeing the many
> discussion on patch v2 I had the feeling that it was not the final solution.
The actual patch is fine I think.
The discussion was about improving the explanation of exactly what's
happening in the change log, and whether there is a larger bug causing
FP corruption unrelated to io-uring.
I'm now reasonably confident there's no detectable corruption of fr0
happening except via the io-uring -> clone path.
It's still a bad bug for us to corrupt fr0 across sys_clone(), but in
practice it doesn't affect userspace because fr0 is volatile across
function calls.
cheers
next prev parent reply other threads:[~2023-11-28 0:59 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-19 15:18 [PATCH v2] powerpc: Don't clobber fr0/vs0 during fp|altivec register save Timothy Pearson
2023-11-20 7:10 ` Michael Ellerman
2023-11-20 14:32 ` Nicholas Piggin
2023-11-20 16:45 ` Timothy Pearson
2023-11-20 16:45 ` Timothy Pearson
2023-11-20 23:39 ` Michael Ellerman
2023-11-20 23:39 ` Michael Ellerman
2023-11-21 0:27 ` Nicholas Piggin
2023-11-21 0:27 ` Nicholas Piggin
2023-11-21 1:23 ` Timothy Pearson
2023-11-21 1:23 ` Timothy Pearson
2023-11-21 7:56 ` Nicholas Piggin
2023-11-21 7:56 ` Nicholas Piggin
2023-11-21 4:10 ` Timothy Pearson
2023-11-21 4:10 ` Timothy Pearson
2023-11-21 4:26 ` Timothy Pearson
2023-11-21 4:26 ` Timothy Pearson
2023-11-21 7:54 ` Nicholas Piggin
2023-11-21 7:54 ` Nicholas Piggin
2023-11-22 5:01 ` Michael Ellerman
2023-11-22 5:01 ` Michael Ellerman
2023-11-24 0:01 ` Timothy Pearson
2023-11-24 0:01 ` Timothy Pearson
2023-11-27 18:39 ` Timothy Pearson
2023-11-27 18:39 ` Timothy Pearson
2023-11-27 19:58 ` Christophe Leroy
2023-11-27 19:58 ` Christophe Leroy
2023-11-28 0:59 ` Michael Ellerman [this message]
2023-11-28 0:59 ` Michael Ellerman
2023-11-28 1:40 ` Nicholas Piggin
2023-11-28 1:40 ` Nicholas Piggin
2023-11-27 22:53 ` Michael Ellerman
2023-11-27 22:53 ` Michael Ellerman
2023-11-28 12:57 ` Michael Ellerman
2023-11-28 12:57 ` Michael Ellerman
2023-11-30 16:29 ` Timothy Pearson
2023-11-30 16:29 ` Timothy Pearson
2023-11-21 0:18 ` Nicholas Piggin
2023-11-21 0:18 ` Nicholas Piggin
2023-12-02 23:00 ` Michael Ellerman
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