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

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

> -----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-20aa
> > > > > -
> > > > >
> > > >
> > >
> 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.html
> > > > 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