RE: [PATCH 32 0/2] Handle the new .note section introduced in Linux

["Schimpe, Christina" <christina.schimpe@intel.com>]

I currently see two open items in this series, and I was wondering if Simon or John might have
additional input on them.

Regarding the missing gdbserver implementation:
IIUC we must send the offset and size information using the remote protocol. Or do we have any
other options?

Concerning the testing topic:
My understanding is that, at the time when the workaround was not yet part of GDB, we observed
some failing tests on AMD CPUs. Is that correct?

In my view, it should be sufficient to verify that these tests are still passing when running
on a sufficiently recent kernel version. And maybe additionally checking that the note exists.

Thanks,
Christina


> -----Original Message-----
> From: Schimpe, Christina
> Sent: Freitag, 13. März 2026 15:09
> To: 'Balasubrmanian, Vignesh' <Vignesh.Balasubrmanian@amd.com>; 'gdb-
> patches@sourceware.org' <gdb-patches@sourceware.org>; 'George, Jini
> Susan' <JiniSusan.George@amd.com>; 'Sharma, Alok Kumar'
> <AlokKumar.Sharma@amd.com>; 'jhb@FreeBSD.org' <jhb@FreeBSD.org>;
> 'simark@simark.ca' <simark@simark.ca>
> Subject: RE: [PATCH 32 0/2] Handle the new .note section introduced in Linux
> 
> > -----Original Message-----
> > From: Schimpe, Christina
> > Sent: Mittwoch, 11. März 2026 10:51
> > To: 'Balasubrmanian, Vignesh' <Vignesh.Balasubrmanian@amd.com>; 'gdb-
> > patches@sourceware.org' <gdb-patches@sourceware.org>; 'George, Jini
> > Susan' <JiniSusan.George@amd.com>; 'Sharma, Alok Kumar'
> > <AlokKumar.Sharma@amd.com>; 'jhb@FreeBSD.org' <jhb@FreeBSD.org>;
> > 'simark@simark.ca' <simark@simark.ca>
> > Subject: RE: [PATCH 32 0/2] Handle the new .note section introduced in
> > Linux
> >
> > > > It looks like my previous message was sent without a subject while
> > > > I was trying to reply to your email thread. I may have used the
> > > > wrong command, or there might have been a glitch with my git
> > > > send-email
> > setup.
> >
> > For such issues it usually helps me to send the email to myself first.
> >
> > For the review:
> > I started digging into this and am ramping up on the history of this
> > topic, since the discussions for this started in 2022 which I didn't follow.
> >
> > But I should be able to have some comments soon.
> >
> > Christina
> >
> > > -----Original Message-----
> > > From: Schimpe, Christina
> > > Sent: Freitag, 6. März 2026 09:14
> > > To: Balasubrmanian, Vignesh <Vignesh.Balasubrmanian@amd.com>; gdb-
> > > patches@sourceware.org; George, Jini Susan
> > <JiniSusan.George@amd.com>;
> > > Sharma, Alok Kumar <AlokKumar.Sharma@amd.com>; jhb@FreeBSD.org;
> > > simark@simark.ca
> > > Subject: RE: [PATCH 32 0/2] Handle the new .note section introduced
> > > in Linux
> > >
> > > Thank you for the update. I'll do the review as soon possible.
> > >
> > > Kind Regards,
> > > Christina
> > >
> > > > -----Original Message-----
> > > > From: Balasubrmanian, Vignesh <Vignesh.Balasubrmanian@amd.com>
> > > > Sent: Freitag, 6. März 2026 08:42
> > > > To: Schimpe, Christina <christina.schimpe@intel.com>; gdb-
> > > > patches@sourceware.org; George, Jini Susan
> > > <JiniSusan.George@amd.com>;
> > > > Sharma, Alok Kumar <AlokKumar.Sharma@amd.com>;
> jhb@FreeBSD.org;
> > > > simark@simark.ca
> > > > Subject: RE: [PATCH 32 0/2] Handle the new .note section
> > > > introduced in Linux
> > > >
> > > > [AMD Official Use Only - AMD Internal Distribution Only]
> > > >
> > > > Thanks Christina,
> > > >
> > > > Please review this last update
> > > > https://sourceware.org/pipermail/gdb-
> > > > patches/2026-February/224832.html
> > > >
> > > > It looks like my previous message was sent without a subject while
> > > > I was trying to reply to your email thread. I may have used the
> > > > wrong command, or there might have been a glitch with my git
> > > > send-email
> > setup.
> > > >
> > > > thanks,
> > > > Vigneshbalu.
> > > >
> > > > -----Original Message-----
> > > > From: Schimpe, Christina <christina.schimpe@intel.com>
> > > > Sent: Friday, March 6, 2026 12:38 PM
> > > > To: Balasubrmanian, Vignesh <Vignesh.Balasubrmanian@amd.com>;
> gdb-
> > > > patches@sourceware.org; George, Jini Susan
> > > <JiniSusan.George@amd.com>;
> > > > Sharma, Alok Kumar <AlokKumar.Sharma@amd.com>;
> jhb@FreeBSD.org;
> > > > simark@simark.ca
> > > > Subject: RE: [PATCH 32 0/2] Handle the new .note section
> > > > introduced in Linux
> > > >
> > > > Caution: This message originated from an External Source. Use
> > > > proper caution when opening attachments, clicking links, or responding.
> > > >
> > > >
> > > > Hi Vignesh,
> > > >
> > > > unfortunately, I missed your message. I am not sure how this could
> > > > have slipped and then I've been out for a couple of weeks.
> > > >
> > > > If you don't hear back from me, please ping me in the mailing lists.
> > > > We have this guideline:
> > > > https://sourceware.org/gdb/wiki/ContributionChecklist
> > > >
> > > > You can expect my feedback on this next week.
> > > >
> > > > Christina
> > > >
> > > > > -----Original Message-----
> > > > > From: Balasubrmanian, Vignesh <Vignesh.Balasubrmanian@amd.com>
> > > > > Sent: Dienstag, 6. Januar 2026 07:49
> > > > > To: Schimpe, Christina <christina.schimpe@intel.com>; gdb-
> > > > > patches@sourceware.org; George, Jini Susan
> > > > <JiniSusan.George@amd.com>;
> > > > > Sharma, Alok Kumar <AlokKumar.Sharma@amd.com>;
> > jhb@FreeBSD.org;
> > > > > simark@simark.ca
> > > > > Subject: RE: [PATCH 32 0/2] Handle the new .note section
> > > > > introduced in Linux
> > > > >
> > > > > [AMD Official Use Only - AMD Internal Distribution Only]
> > > > >
> > > > > Hi Christina,
> > > > >
> > > > > In my test, I read the core file's new note-section data with
> > > > > the program and compare it against the "cupid" instructions. I
> > > > > couldn't find any existing test that validates note-section
> > > > > contents. If full validation is too much, I can instead extend
> > > > > "maint-info-sections.exp" to
> > > > check only that the section exists.
> > > > >
> > > > > Please advise.
> > > > >
> > > > > thanks.
> > > > > Vigneshbalu.
> > > > >
> > > > > -----Original Message-----
> > > > > From: Schimpe, Christina <christina.schimpe@intel.com>
> > > > > Sent: Sunday, December 14, 2025 7:09 PM
> > > > > To: Balasubrmanian, Vignesh <Vignesh.Balasubrmanian@amd.com>;
> > gdb-
> > > > > patches@sourceware.org; George, Jini Susan
> > > > <JiniSusan.George@amd.com>;
> > > > > Sharma, Alok Kumar <AlokKumar.Sharma@amd.com>;
> > jhb@FreeBSD.org;
> > > > > simark@simark.ca
> > > > > Subject: RE: [PATCH 32 0/2] Handle the new .note section
> > > > > introduced in Linux
> > > > >
> > > > > Caution: This message originated from an External Source. Use
> > > > > proper caution when opening attachments, clicking links, or responding.
> > > > >
> > > > >
> > > > > Hi Vignesh,
> > > > >
> > > > > I'll review the patches once we have clarified the opens for the test.
> > > > > Please see my comment below.
> > > > >
> > > > > > -----Original Message-----
> > > > > > From: Vignesh Balasubramanian <vigbalas@amd.com>
> > > > > > Sent: Montag, 8. Dezember 2025 09:38
> > > > > > To: gdb-patches@sourceware.org; jinisusan.george@amd.com;
> > > > > > Schimpe, Christina <christina.schimpe@intel.com>;
> > > AlokKumar.Sharma@amd.com;
> > > > > > jhb@FreeBSD.org; simark@simark.ca
> > > > > > Cc: Vignesh Balasubramanian <vigbalas@amd.com>
> > > > > > Subject: [PATCH 32 0/2] Handle the new .note section
> > > > > > introduced in Linux
> > > > > >
> > > > > > The XSAVE layout of the machine where the core file is dumped
> > > > > > is not visible to GDB. It is assumed currently using some heuristics.
> > > > > >
> > > > > > It has been addressed to some extent recently but still uses heuristics.
> > > > > > https://inbox.sourceware.org/gdb-patches/2628f45a-77f7-8b2c-20
> > > > > > aa
> > > > > > -
> > > > > >
> > > > >
> > > >
> > da65d1d82a37@simark.ca/T/#m4c67d59c18a5962f771ba8ca1e2bee9365ad
> > > > > > 1ab2
> > > > > >
> > > > > > New patches have been committed to the linux kernel (version
> > > > > > 6.12) to resolve this issue by adding a new .note section
> > > > > > which contains descriptions of the xsave layout to the core file.
> > > > > >
> > > > > > The first of this patch set consumes this new .note section
> > > > > > and uses that to identify the xsave layout.
> > > > > > The second one enables gdb to generate a similar .note section
> > > > > > if the corefile is dumped through the 'gcore' command.
> > > > > >
> > > > > > Working on test case patch, will share it in a few days.
> > > > >
> > > > > In the gdb testsuite we already have tests for (g)core commands
> > > > > and for OS generated corefiles.
> > > > >
> > > > > Based on the test that you shared initially
> > > > > https://sourceware.org/pipermail/gdb-patches/2025-July/219369.ht
> > > > > ml I wonder what your test will cover that is not tested already
> > > > > with existing tests.
> > > > >
> > > > > Would it be sufficient to extend the existing tests in case a
> > > > > linux kernel >=
> > > > > 6.12 is used ?
> > > > >
> > > > > Christina
> > > > >
> > > > > Intel Deutschland GmbH
> > > > > Registered Address: Dornacher Straße 1, 85622 Feldkirchen,
> > > > > Germany
> > > > > Tel: +49 89 991 430, www.intel.de Managing Directors: Harry
> > > > > Demas, Jeffrey Schneiderman, Yin Chong Sorrell Chairperson of
> > > > > the Supervisory Board: Nicole Lau Registered
> > > > > Seat: Munich Commercial Register: Amtsgericht München HRB 186928
> > > > Intel Deutschland GmbH
> > > > Registered Address: Dornacher Straße 1, 85622 Feldkirchen, Germany
> > > > Tel: +49 89 991 430, www.intel.de
> > > > Managing Directors: Harry Demas, Jeffrey Schneiderman, Yin Chong
> > > > Sorrell Chairperson of the Supervisory Board: Nicole Lau
> > > > Registered
> > > > Seat: Munich Commercial Register: Amtsgericht München HRB 186928
> 
> Hi Vignesh,
> 
> I did not investigate the detailed code of your test, as I still wonder about the
> general direction.
> I should have more ideas next week.
> 
> One question I have in the meantime:
> 
> Is there any specific reason why the note is not implemented for gdbserver ?
> 
> I think it would be good to have it all together.
> 
> One small patch for a new corefile note (including gdbserver support) is this
> one:
> "gdb: amd64 linux coredump support with shadow stack."
> 
> Maybe it helps you to dig into this.
> 
> Thanks,
> Christina
> 
> 

Intel Deutschland GmbH
Registered Address: Dornacher Straße 1, 85622 Feldkirchen, Germany
Tel: +49 89 991 430, www.intel.de
Managing Directors: Harry Demas, Jeffrey Schneiderman, Yin Chong Sorrell
Chairperson of the Supervisory Board: Nicole Lau
Registered Seat: Munich
Commercial Register: Amtsgericht München HRB 186928