DFG Heisenberg post-mortem, part 2

This post contains remaining parts of my DFG Heisenberg grant final report, by now long submitted and accepted by the DFG. I hope it will be of use, in particular to future DFG grant candidates. The text also somewhat explains why I'm fed up with academia, Regensburg, and physics right now (in no particular order and to varying degrees). The first part of the report can be found in a previous post. Some personal information has been redacted.

Qualification, career, …

During the Heisenberg period 2021-2026, submitted applications for professorships resulted in 8 invitations for presentation and discussion: [...]

A recurrent topic over all my years in academia was that appointment procedures for professorships either failed or that positions were handed to local Emmy Noether, Heisenberg, Juniorprofessor, etc. candidates – much more than expected from past times when the spectre of unwanted “Hausberufung” (in-house appointment) was looming over such events. From that point of view it was equally disappointing that, once I applied for a position in Regensburg, I was immediately told by a member of the appointment commission that my application would be sorted out for exactly that reason. When I spoke to an external member of the appointment commission for that professorship, that external member did not even know that I had applied for the position. In parallel, somewhat doubtful direct appointments to professorships took place in the department.

Further frustration originated from the fact that the Regensburg physics department decided to rewrite their internal regulations such that even after 6 years of Privatdozentur (senior lecturer with habilitation) they only award the title of Außerordentlicher Professor (associated professor, a title without salary) to candidates with a permanent university position. My corresponding petition never received any written response, only oral comment that this is not done anymore. The motivation behind all this is unclear, but it certainly does not make Regensburg more attractive to (somewhat) junior scientists.

A four-eyes career conversation with Mr. Dean of the Faculty resulted in charming comments such as “the best we can do is half an E13 position in the experimental collection maintenance of the undergraduate lectures in a year or so, maybe you could do some research on the side there” and “as a Heisenberg you are an academic legacy problem” (the original German term was “akademische Altlast”). Plus remarks like “we are not going to hand out any (even unpaid) teaching assignments (“Lehraufträge”) to an external Privatdozent anymore, so you’ll lose that title anyway soon for lack of teaching.”

The final cherry on top was then getting berated by another influential senior faculty member about producing insufficient results and being unable to supervise – which is pretty thick coming from someone who barely finds any MSc students, having a reputation among students for erratic grading there. To quote a colleague from Regensburg with permanent employment who should probably stay anonymous, “Der professorale Dünkel ist stark in der Fakultät” (roughly translated, the professorial sense of self-importance is tantamount in the department).

With all these experiences as background, I strongly recommend to anyone with a grant such as DFG Emmy Noether or Heisenberg not to join the Regensburg physics department, but go somewhere else. You and your work will be valued more, and that by far compensates for any Regensburg “excellence”. [...]

Teaching and scientific events

With already significant teaching experience, I decided to mostly focus on research and supervision during the Heisenberg period – with the exception of a “Low Temperature Physics” course where the usual lecturer was on sabbatical. Regarding scientific events, I had requested a moderate amount of funding for a workshop on inorganic nanotubes in [...], which would have fitted quite well as add-on to the workshops of SFB 1277. This was however declined – accordingly, it also did not have priority for me anymore either.

Perspective

I enjoyed university research and teaching as well as working with students, establishing a research group, quantum device fabrication, and complex measurements very much. With the “orderly shutdown” of the group comes that still some students need to graduate and that some results will still be written up and submitted for publication (at the time of this report two papers have been submitted and another two or three might follow); however, I have cleared out my office the day of the end of my employment contract. 

Out of a certain stubbornness, I will keep teaching my 2SWS per year Titellehre for now – as confirmed by the faculty administration, a teaching appointment (“Lehrauftrag”) is legally not required for that, and as a consequence the students will be treated to a block course “How to write a thesis, present a talk, …” in October. However, after over 15 years in Regensburg I have learned that being nice, friendly, cooperative, and helpful might get you friendly smiles and occasional money there but not any sustainable support, and that the Regensburg physics system prefers “junior scientists” to be subordinates, not colleagues. Of course someone who does not have the visible backing of his current university immediately also has a weaker position when applying elsewhere. 

There’s a lot more I could write, but that would go beyond scope and purpose of this report. Anyway, it is now time to make a bonfire out of lecture notes, to go out into the wide world, and to do something entirely new. Which, barring big surprises, most likely will not involve physics or a university anymore. 

Thanks to Duong Thi Hai Yen on vecteezy.com for the tomato.

DFG Heisenberg project post-mortem

This post is an excerpt from the formally non-public part of my DFG Heisenberg grant final report (about half of the actually interesting part). I hope it will help people do better. The remaining part of the report can be found in a subsequent blog post. Some personal information has been redacted.

The backstory

In 2018, when I first submitted a Heisenberg program proposal, funding was declined. One referee report was full of misinformation and misinterpretations, the other criticized the methods in one of the suggested research subtopics. Overall this sufficiently lowered the ranking of the entire submission. Anyway, as the saying goes, stand up again, brush down coat, re-adjust crown, keep going. The proposal was updated, the doubtful part replaced, a response to the misinformation added, and of course also some more exciting research ideas included.

At that point I decided to go for full risk. While the DFG Emmy Noether program deliberately funds a junior research group consisting of a PI and PhD students or a post-doc, the DFG Heisenberg program is more adjusted along the customs of humanities and funds the PI alone. It is still supposed to provide a base for independent research at the level of associate professor though, which is why one can concurrently submit a supporting research grant proposal for equipment and personnel. The advantage of doing so is that this can form a coherent overall funding package, the disadvantage is that a negative review of any part of the package will drag it down in its entirety, see above.

Complementing the overarching Heisenberg proposal for my own position and its research, I submitted in 2019 two additional research proposals ("Einzelanträge"). One focused on the continuation of the Emmy Noether project, tuning optomechanics of single-wall carbon nanotubes towards strong coupling and coherent control, and including such nice ideas as, e.g., coupling mechanics with coherent states in double quantum dots. This was a highly complex project, intended for two PhD students (and the two students were really required because of the combination of multi-step fabrication and complicated experiment). In addition, it was adjusted to fit to the topic of a Graduate Research School (GRK) proposal under preparation back then in Regensburg. The idea of the second grant was to try out something new, and establish quantum transport measurements on MoS₂ nanotubes – a material where already a lot of optical measurements existed but the transport physics of quantum dots was so far completely unexplored. Here, one PhD student was requested; furthermore the topic was deliberately chosen to be in the area of interest of a new Regensburg Collaborative Research Centre (SFB), SFB 1277, in the hope of further financial support options.

Because of the significant amount of university-bound equipment acquired from SFB funds, and the potential difficulties of moving “my” large dilution refrigerator, I chose again Universität Regensburg as host institution.

In the meantime, my employment contract in Regensburg ran out (thanks Wissenschaftszeitvertragsgesetz), so I went to the Low Temperature Laboratory, Department of Applied Physics, Aalto University, Finland for one year as full-time employed visiting professor; my thanks go to Prof. Pertti Hakonen for making this possible. Two weeks later COVID broke out, but Aalto was a great place to be both scientifically and to sit out the pandemic. And in autumn a sequence of excellent news followed; the Heisenberg grant was approved, and in addition the Emmy Noether work on microwave optomechanics was awarded the Walter Schottky Prize 2021 of the German Physical Society. So, things were clearly brightening up, or so I thought.

A more detailed inspection of the grant approval letter provided a somewhat more mixed image. One referee explicitly and clearly supported the request for two PhD students in the optomechanics project, the other also explicitly lauded all details, including the excellent funding plan, of the optomechanics project, but additionally stated that the impact of the MoS₂ nanotube project would be larger (this was likely written before the announcement of the Walter Schottky Prize). As result, only one PhD position for optomechanics was granted by the funding committee. Hope always dies last, but in retrospect I can now confirm my immediate suspicion that this reduction of funding killed the optomechanics project from the start. My initial “plan B” for additional optomechanics funds was not available anymore, since the Regensburg Graduate Research School had in the meantime made an ultrafast turn towards other research topics. Further, even though this project was the direct continuation of the Walter Schottky Prize work, it turned out to be extremely difficult to find and hire a PhD student for it. The project started on 16 March 2021, and only on 1 August 2022 a PhD student arrived.

In comparison, the MoS₂ nanotube project start-up went much more smooth, and [...] started work on his PhD straight on the 16 March 2021. All hope of a financially significant participation in the Regensburg SFB 1277 was however shattered already by a brief conversation with the back then SFB speaker, who made clear that nothing beyond appointing me “associated member” would even be considered. Well, you can't allow “junior scientists” to become too successful…

Scientific progress

I had attempted to keep the optomechanics project going in Regensburg during my time in Finland via a remotely-supervised MSc student, who successfully optimized coplanar waveguide resonator geometries and produced and tested the corresponding devices. When I came back, I quickly found another MSc student who was very enthusiastic to start with optomechanics experiments. However, we also quickly found out that the nanotube growth oven had broken in the meantime, requiring the whole process to be optimized from the start, and the MSc project literally became a year of getting carbon nanotube growth going again from zero. Now in 2026 (!) the quality of nanotubes transferred into a circuit is finally showing excellent results again. That said, the nanotube optomechanics project had many delicate parts, from nanotube growth and transfer to coplanar resonator chip design and fabrication, and no number of MSc students recruited into my group could really replace the missing second PhD student.

[...] On the MoS₂ nanotube side, progress was slow but steady, and the PhD student did excellent work. Making contacts to MoS₂ nanotubes turned out to be even more complex than contacts to carbon nanotubes or a 2D MoS₂ monolayer. A technical breakthrough in the latter system by researchers from MIT and TSMC, among others, provided a path forward, and indeed their approach also led to occasional good results with the MoS₂ nanotubes. Obtaining these good results reproducibly, however, was again another complex optimization step; we solved that in 2025 and subsequently managed first physically interesting low-temperature measurements.

In general, across both subprojects, work was slowed down very much by continuous equipment break-downs and oddities in the Regensburg cleanroom. "The SEM for e-beam writing is down" turned out to be one highly regular e-mail subject (for any possible value of "the SEM"). Mystery changes in resist properties, micrometer-scale shifts in the written structures, interruptions in the air conditioning that led to water condensation in the whole cleanroom, ... The department bought a Heidelberg Instruments mask-less aligner (a laser writer for lithography), which was nice but of limited usefulness – since for nanophysics you actually need nano-resolution! Plus there were some other annoying events; e.g., during the installation of a new dilution refrigerator next door someone opened up our (then evacuated) 3He/4He circuit in the pump room to air, which we only noticed when we tried to cool down and suddenly were pumping air into the cold dilution refrigerator insert. Luckily, nearly no isotope mixture was lost.

Experimental work took significantly longer than expected, but eventually did yield interesting results right at the end. As stated above, for the research details of the two subprojects, I refer to the final reports of the research grants [...] and [...].

[...]

Early career stage researchers

I am proud to be able to say that during my ~16 years in Regensburg I have supervised 7 PhD students and 27 MSc or Diplom students. During the Heisenberg period specifically, two PhD students should be named, [...] and [...]. [...] is currently helping a new professor in Regensburg build up his lab on a post-doc position and considering remaining in academia (which he would definitely be suited for). [...] is still busy measuring beautiful data and writing up his dissertation, while being paid by SFB1277.

At the end of the official project runtime (and my employment) in March three MSc students were still active; two have graduated by now, the third one recently handed in his thesis.

A magic dwells in each beginning

"A magic dwells in each beginning" / "Und jedem Anfang wohnt ein Zauber inne" - this famous line of the poem "Stufen", written by Hermann Hesse over 80 years ago, comes to my mind when posting a bittersweet update here. After over 16 years of independent research and teaching at the physics department of Universität Regensburg, my Heisenberg grant and with that my last university employment contract runs out.

The years in Regensburg included the Emmy Noether grant of the DFG, being PI in two Collaborative Research Centres (SFB) and one Graduate Research Training Group (GRK), a successful large equipment grant, the habilitation, the Walter Schottky Prize of the German Physical Society, and the Heisenberg scholarship of the DFG with positive evaluation. In addition, I have independently supervised 7 PhD students and 27 MSc or diploma students, and developed and conducted both undergraduate and graduate lectures. Third-party research funding from my grants at Universität Regensburg amounts to approximately € 2.6M, of which € 2.1M was for grants solely within my research group, the rest part of larger collaborations. 

Over the years, my research group in Regensburg has among other things successfully built up ultra-clean carbon nanotube devices for electronics and nano-electromechanics, the fabrication of high-Q superconducting coplanar electronics and milli-Kelvin microwave measurements, the transfer of carbon nanotubes into complex devices, the first ever microwave optomechanics experiment with a carbon nanotube, and Coulomb blockade spectroscopy of MoS₂ nanotubes.

The hardest part of all this time was that without a permanent contract ever the options for acquisition of further grants and independent development of collaborations were severely limited. At the same time one builds up a complex experiment and develops cutting edge techniques without clear perspective. And while the mental model for someone below the professorial level to be an independent group leader and grow sustainably in an academic and professional sense does not really exist in the Regensburg physics department, excellence in exactly this is requested and required by the referees of the various grant programs.

With the high-level DFG money, I have never really been "akademisches Prekariat". However, I fully support initiatives such as PD Prekär and #IchBinHanna which try to ameliorate the situation of researchers in Germany not yet on a permanent professorship. In experimental physics, an unpaid PD working alone at home is of course unthinkable.

I enjoyed university research and teaching as well as working with students, establishing a research group, quantum device fabrication, and complex measurements very much. With the "orderly shutdown" of the group comes that still some students need to graduate and that probably some results will still be written up as papers; however, my office has already been cleared out. I would like to thank everyone who was supportive, in particular also Pertti Hakonen and Milena Grifoni. Nevertheless, it's probably at some point now time to make a bonfire out of those lecture notes, go out into the world and do something entirely new. Which, barring surprises, most likely won't involve physics or a university anymore. I'm lucky in the sense that I'm single and have so far no family or kids to care of.

Time for a gap year and some serious world travel.

 

 

 

Und jedem Anfang wohnt ein Zauber inne

„Und jedem Anfang wohnt ein Zauber inne“ – an diese berühmte Zeile aus dem Gedicht „Stufen“, von Hermann Hesse vor über 80 Jahren verfasst, muß ich denken, wenn ich hier ein bittersüßes Update poste. Nach über 16 Jahren unabhängiger Forschung und Lehre an der Fakultät Physik der Universität Regensburg läuft meine Heisenberg-Stelle und damit mein letzter befristeter Hochschulvertrag aus.

Zu den Jahren in Regensburg gehörten das Emmy-Noether-Stipendium der DFG, die Projektleitung in zwei Sonderforschungsbereichen (SFB) und einer Graduiertenkolleg (GRK), ein erfolgreicher Großgeräteantrag, die Habilitation, der Walter-Schottky-Preis der Deutschen Physikalischen Gesellschaft und das Heisenberg-Stipendium der DFG mit positiver Evaluation. Dazu habe ich eigenverantwortlich 7 Doktoranden und 27 Master- oder Diplomstudenten betreut und Vorlesungen für Bachelor- und Masterstudierende entworfen und abgehalten. Die Drittmittel aus meinen Förderanträgen an der Universität Regensburg belaufen sich auf insgesamt ca. 2,6 Mio. €; davon entfielen 2,1 Mio. € auf Arbeiten ausschließlich innerhalb meiner Forschungsgruppe, der Rest anteilhaft auf größere Kooperationen.

Im Laufe der Jahre hat meine Forschungsgruppe in Regensburg unter anderem erfolgreich ultrareine Kohlenstoffnanoröhren-Bauelemente für Elektronik und Nanoelektromechanik entwickelt, koplanare supraleitende Elektronik mit hohen Qualitätsfaktoren und Millikelvin-Mikrowellenmessungen aufgebaut, Kohlenstoffnanoröhren in komplexe Bauelemente übertragen, das erste Mikrowellen-Optomechanik-Experiment mit einer Kohlenstoffnanoröhre durchgeführt und Coulomb-Blockade-Spektroskopie von MoS₂-Nanoröhren gemessen.

Das Schwierigste an der Zeit in Regensburg war, daß ohne unbefristeten Vertrag die Einwerbung weiterer Fördermittel und die unabhängige Entwicklung von Kooperationen nur stark eingeschränkt möglich waren. Gleichzeitig baut man ein komplexes Experiment auf und entwickelt modernste Techniken ohne klare Perspektive. Und während das mentale Modell, daß jemand unterhalb der Professorenebene ein unabhängiger Arbeitsgruppenleiter sein und sich in akademischer und beruflicher Hinsicht nachhaltig weiterentwickeln kann, in der Physik in Regensburg nicht wirklich existiert, wird genau dies von den Gutachtern der verschiedenen Förderprogramme verlangt.

Dank der hochkarätigen DFG-Förderung war ich nie wirklich "akademisches Prekariat". Trotzdem unterstütze ich voll und ganz Initiativen wie PD Prekär und #IchBinHanna, die versuchen, die Situation von Forschern ohne unbefristete Stelle oder Professur in Deutschland zu verbessern. In der experimentellen Physik ist ein unbezahlter Privatdozent, der allein zu Hause arbeitet, natürlich undenkbar.

Forschung und Lehre an der Universität sowie die Arbeit mit Studierenden, der Aufbau einer Forschungsgruppe, die Herstellung von Quantenbauelementen und entsprechende komplexe Messungen haben mir sehr viel Spaß gemacht. Mit dem "geregelten Herunterfahren" der Arbeitsgruppe werden noch ein paar Studenten ihren Abschluß machen, und vielleicht werden auch noch einige Resultate als Papers eingereicht; mein Büro habe ich allerdings schon geräumt. Mein Dank gilt allen, die mich unterstützt haben, insbesondere auch Pertti Hakonen und Milena Grifoni. Dann ist es aber demnächst wohl Zeit für ein Feuerchen aus Vorlesungsskripten, und dafür, hinaus in die Welt zu ziehen und sich mit etwas völlig Neuem zu beschäftigen. Was, von Überraschungen abgesehen, höchstwahrscheinlich nichts mehr mit Physik oder einer Universität zu tun haben wird. Zum Glück bin ich Single und habe soweit keine Familie oder Kinder...

Zeit für eine Auszeit - und für eine Weltreise.

 

 

Ready-to-boot, fresh & experimental Gentoo QCOW2 disk images

Recently I've been experimenting with Catalyst, the tool that generates stages and iso files for Gentoo's Release Engineering team. The first, still very experimental result is now available for download - a bootable hard disk image in QEmu's qcow2 format that immediately drops you into a fully working Gentoo environment.

Feel free to download it and try it out, either this first upload or any future weekly build from the amd64 release file directories. The files are not linked on the www.gentoo.org webserver since I consider them not really finished yet, but instead experimental and under development. You can use a QEmu commandline as for example

qemu-system-x86_64 \
       -m 8G -smbios type=0,uefi=on -bios /usr/share/edk2-ovmf/OVMF_CODE.fd \
       -smp 4 -cpu host -accel kvm -vga virtio -drive file=di.qcow2 &

where the last "file" argument specifies the file that you downloaded, for testing.

The current download initially does not start any network login services such as sshd, but has an empty root password for logging in on the console - this is why I call it a "console" type disk image. Future variants I'm planning include for example a "cloud-init" type, which sets up log-in credentials and further configuration as supplied by a cloud provider.

Cheers and enjoy!

Rating scientific (or not so much) conferences

If you work in research, nowadays you can be sure to get swamped with "conference invitation" e-mails. A large part of these is, in effect, spam - attempts to get you (or your funders) to pay for meetings of highly questionable scientific worth.

So, let's introduce a rating scale for scientific (or not) conferences, from 0 to 10. All examples have really happened.

0 - Trash

• You ask a friend who is listed in the organizing committee, and get the response "what conference?"
  
• Advertising mostly mentions the location (Maledives!) and the proceedings (Indexed by Google Scholar!)
  
• You arrive at the location and there is no conference.
• If there is one, you can barely find it because it's in the back room of some hotel conference center.
• Instead of a conference organizer's desk you encounter a pile of badges and participation certificates.
• The "hybrid session" consists of you, the AV technician, and some poor guy on zoom talking to a non-existing audience.
• There's a talk on the "memory of water".
• A remote talk is given by someone in a car while driving.
• There are less posters than talks.
  

3 - We do this for the money, but hey, we're trying!

• The conference organizing committee contains the one or two well-known professors who are in every organizing committee. Everyone else is from countries you've never heard of.
• The meeting has taken place before and the website is somewhat professional.
• The conference secretary is called Elsa, Belle, or Jasmine and sends you an e-mail every week, offering an invited talk for a "small reduction" of the conference fee (hint, the size of the reduction can be up to negotiation!)
• Between sign-up and actual conference date, the number of days and sessions mysteriously shrinks.
  
• The conference organizer's desk is handled by a bunch of undergrads who barely speak English and have no clue.
• The welcome address is skipped since the speaker doesn't turn up. Same for the chairman of the first session. After the first regular speaker starts their talk, the chairman hurries in - "sorry, sorry, I ended up at the wrong conference..."
  
• You meet a few colleagues from home who find the situation similarly amusing as you, and have a good time at lunch.
• Eventually things become somewhat more regular, and sessions and talks take place, but you have quite some doubts about the scientific quality of some of them.
• Focus? What focus?
  

6 - Yes I'm gonna establish a conference, mark my words!

• 5th or 6th installment of a conference series, typically by the same scientific organizer or organization.
• You find the conference without problems, and there is actually a well-organized conference desk. Maybe even the scientific organizer greets you in person.
  
• The location is only moderately flashy, function starts to gain over form.
  
• Most of the participants are from serious scientific institutions and present work that can be interesting.
• Main problem is still the focus - the topics are too broad, the number of participants too small, such that it's not so likely you will meet someone whose work is really relevant to your own.
• If the main organizer has a good hand, they will accumulate a circle of regular participants and the event will grow over time.
• Can, e.g., be a professor establishing an international conference on their topic in their home country...
• Typically 2-3 companies are present trying to sell their lab supplies.
  

9 - Congratulations, it's a great scientific conference

• Either wide focus and a huge number of participants, or narrow focus and a small number of participants
• Organized by a scientific society (DPG, EPS, APS, ...) or by a group of internationally well-known experts in one specific field
• True invited talks are comparatively rare, and come with (depending on the financial situation of the host) either no reduction of fees at all, or even funding of travel expenses.
• You know nearly everyone in the organizing committee, at least from their publications.
  
• Many more poster contributions than talks.
• You can be sure to meet many of your scientific colleagues.
• Large commercial presence of companies sponsoring the meeting and advertising their high-tech equipment.
  

10 - Summa cum laude

• Small meetings organized by few top experts of a research area, or (very rare) large meetings consisting of several such high-quality sessions in combination.
  
• Organized by top level scientists in the field worldwide
  
• Participation by invitation only, true selection of conference participants (more applicants than places)
• In some cases, even free participation and accommodation
  
• Recent examples: Gordon Research Conferences, Heraeus seminars, the QuantuMatter 2024, ... 

 Thoughs?

 

The GNU C Library version 2.40 is now available

The GNU C Library
=================

The GNU C Library version 2.40 is now available.

The GNU C Library is used as *the* C library in the GNU system and
in GNU/Linux systems, as well as many other systems that use Linux
as the kernel.

The GNU C Library is primarily designed to be a portable
and high performance C library.  It follows all relevant
standards including ISO C11 and POSIX.1-2017.  It is also
internationalized and has one of the most complete
internationalization interfaces known.

The GNU C Library webpage is at http://www.gnu.org/software/libc/

Packages for the 2.40 release may be downloaded from:
        http://ftpmirror.gnu.org/libc/
        http://ftp.gnu.org/gnu/libc/

The mirror list is at http://www.gnu.org/order/ftp.html

Distributions are encouraged to track the release/* branches
corresponding to the releases they are using.  The release
branches will be updated with conservative bug fixes and new
features while retaining backwards compatibility.

NEWS for version 2.40
=====================

Major new features:

* The <stdbit.h> header type-generic macros have been changed when using
  GCC 14.1 or later to use __builtin_stdc_bit_ceil etc. built-in functions
  in order to support unsigned __int128 and/or unsigned _BitInt(N) operands
  with arbitrary precisions when supported by the target.

* The GNU C Library now supports a feature test macro _ISOC23_SOURCE to
  enable features from the ISO C23 standard.  Only some features from
  this standard are supported by the GNU C Library.  The older name
  _ISOC2X_SOURCE is still supported.  Features from C23 are also enabled
  by _GNU_SOURCE, or by compiling with the GCC options -std=c23,
  -std=gnu23, -std=c2x or -std=gnu2x.

* The following ISO C23 function families (introduced in TS
  18661-4:2015) are now supported in <math.h>.  Each family includes
  functions for float, double, long double, _FloatN and _FloatNx, and a
  type-generic macro in <tgmath.h>.

  - Exponential functions: exp2m1, exp10m1.

  - Logarithmic functions: log2p1, log10p1, logp1.

* A new tunable, glibc.rtld.enable_secure, can be used to run a program
  as if it were a setuid process. This is currently a testing tool to allow
  more extensive verification tests for AT_SECURE programs and not meant to
  be a security feature.

* On Linux, the epoll header was updated to include epoll ioctl definitions
  and the related structure added in Linux kernel 6.9.

* The fortify functionality has been significantly enhanced for building
  programs with clang against the GNU C Library.

* Many functions have been added to the vector library for aarch64:
    acosh, asinh, atanh, cbrt, cosh, erf, erfc, hypot, pow, sinh, tanh

* On x86, memset can now use non-temporal stores to improve the performance
  of large writes. This behaviour is controlled by a new tunable
  x86_memset_non_temporal_threshold.

Deprecated and removed features, and other changes affecting compatibility:

* Architectures which use a 32-bit seconds-since-epoch field in struct
  lastlog, struct utmp, struct utmpx (such as i386, powerpc64le, rv32,
  rv64, x86-64) switched from a signed to an unsigned type for that
  field.  This allows these fields to store timestamps beyond the year
  2038, until the year 2106.  Please note that applications are still
  expected to migrate off the interfaces declared in <utmp.h> and
  <utmpx.h> (except for login_tty) due to locking and session management
  problems.

* __rseq_size now denotes the size of the active rseq area (20 bytes
  initially), not the size of struct rseq (32 bytes initially).

Security related changes:

The following CVEs were fixed in this release, details of which can be
found in the advisories directory of the release tarball:

  GLIBC-SA-2024-0004:
    ISO-2022-CN-EXT: fix out-of-bound writes when writing escape
    sequence (CVE-2024-2961)

  GLIBC-SA-2024-0005:
    nscd: Stack-based buffer overflow in netgroup cache (CVE-2024-33599)

  GLIBC-SA-2024-0006:
    nscd: Null pointer crash after notfound response (CVE-2024-33600)

  GLIBC-SA-2024-0007:
    nscd: netgroup cache may terminate daemon on memory allocation
    failure (CVE-2024-33601)

  GLIBC-SA-2024-0008:
    nscd: netgroup cache assumes NSS callback uses in-buffer strings
    (CVE-2024-33602)

The following bugs were resolved with this release:

  [19622] network: Support aliasing with struct sockaddr
  [21271] localedata: cv_RU: update translations
  [23774] localedata: lv_LV collates Y/y incorrectly
  [23865] string: wcsstr is quadratic-time
  [25119] localedata: Change Czech weekday names to lowercase
  [27777] stdio: fclose does a linear search, takes ages when many FILE*
    are opened
  [29770] libc: prctl does not match manual page ABI on powerpc64le-
    linux-gnu
  [29845] localedata: Update hr_HR locale currency to €
  [30701] time: getutxent misbehaves on 32-bit x86 when _TIME_BITS=64
  [31316] build: Fails test misc/tst-dirname "Didn't expect signal from
    child: got `Illegal instruction'" on non SSE CPUs
  [31317] dynamic-link: [RISCV] static PIE crashes during self
    relocation
  [31325] libc: mips: clone3 is wrong for o32
  [31335] math: Compile glibc with -march=x86-64-v3 should disable FMA4
    multi-arch version
  [31339] libc: arm32 loader crash after cleanup in 2.36
  [31340] manual: A bad sentence in section 22.3.5 (resource.texi)
  [31357] dynamic-link: $(objpfx)tst-rtld-list-diagnostics.out rule
    doesn't work with test wrapper
  [31370] localedata: wcwidth() does not treat
    DEFAULT_IGNORABLE_CODE_POINTs as zero-width
  [31371] dynamic-link: x86-64: APX and Tile registers aren't preserved
    in ld.so trampoline
  [31372] dynamic-link: _dl_tlsdesc_dynamic doesn't preserve all caller-
    saved registers
  [31383] libc: _FORTIFY_SOURCE=3 and __fortified_attr_access vs size of
    0 and zero size types
  [31385] build: sort-makefile-lines.py doesn't check variable with _
    nor with "^# variable"
  [31402] libc: clone (NULL, NULL, ...) clobbers %r7 register on
    s390{,x}
  [31405] libc: Improve dl_iterate_phdr using _dl_find_object
  [31411] localedata: Add Latgalian locale
  [31412] build: GCC 6 failed to build i386 glibc on Fedora 39
  [31429] build: Glibc failed to build with -march=x86-64-v3
  [31468] libc: sigisemptyset returns true when the set contains signals
    larger than 34
  [31476] network: Automatic activation of single-request options break
    resolv.conf reloading
  [31479] libc: Missing #include <sys/rseq.h> in sched_getcpu.c may
    result in a loss of rseq acceleration
  [31501] dynamic-link: _dl_tlsdesc_dynamic_xsavec may clobber %rbx
  [31518] manual: documentation: FLT_MAX_10_EXP questionable text, evtl.
    wrong,
  [31530] localedata: Locale file for Moksha - mdf_RU
  [31553] malloc: elf/tst-decorate-maps fails on ppc64el
  [31596] libc: On the llvm-arm32 platform, dlopen("not_exist.so", -1)
    triggers segmentation fault
  [31600] math: math: x86 ceill traps when FE_INEXACT is enabled
  [31601] math: math: x86 floor traps when FE_INEXACT is enabled
  [31603] math: math: x86 trunc traps when FE_INEXACT is enabled
  [31612] libc: arc4random fails to fallback to /dev/urandom if
    getrandom is not present
  [31629] build: powerpc64: Configuring with "--with-cpu=power10" and
    'CFLAGS=-O2 -mcpu=power9' fails to build glibc
  [31640] dynamic-link: POWER10 ld.so crashes in
    elf_machine_load_address with GCC 14
  [31661] libc: NPROCESSORS_CONF and NPROCESSORS_ONLN not available in
    getconf
  [31676] dynamic-link: Configuring with CC="gcc -march=x86-64-v3"
    --with-rtld-early-cflags=-march=x86-64 results in linker failure
  [31677] nscd: nscd: netgroup cache: invalid memcpy under low
    memory/storage conditions
  [31678] nscd: nscd: Null pointer dereferences after failed netgroup
    cache insertion
  [31679] nscd: nscd: netgroup cache may terminate daemon on memory
    allocation failure
  [31680] nscd: nscd: netgroup cache assumes NSS callback uses in-buffer
    strings
  [31682] math: [PowerPC] Floating point exception error for math test
    test-ceil-except-2 test-floor-except-2 test-trunc-except-2
  [31686] dynamic-link: Stack-based buffer overflow in
    parse_tunables_string
  [31695] libc: pidfd_spawn/pidfd_spawnp leak an fd if clone3 succeeds
    but execve fails
  [31719] dynamic-link: --enable-hardcoded-path-in-tests doesn't work
    with -Wl,--enable-new-dtags
  [31730] libc: backtrace_symbols_fd prints different strings than
    backtrace_symbols returns
  [31753] build: FAIL: link-static-libc with GCC 6/7/8
  [31755] libc: procutils_read_file doesn't start with a leading
    underscore
  [31756] libc: write_profiling is only in libc.a
  [31757] build: Should XXXf128_do_not_use functions be excluded?
  [31759] math: Extra nearbyint symbols in libm.a
  [31760] math: Missing math functions
  [31764] build: _res_opcodes should be a compat symbol only
  [31765] dynamic-link: _dl_mcount_wrapper is exported without prototype
  [31766] stdio: _IO_stderr_ _IO_stdin_ _IO_stdout should be compat
    symbols
  [31768] string: Extra stpncpy symbol in libc.a
  [31770] libc: clone3 is in libc.a
  [31774] libc: Missing __isnanf128 in libc.a
  [31775] math: Missing exp10 exp10f32x exp10f64 fmod fmodf fmodf32
    fmodf32x fmodf64 in libm.a
  [31777] string: Extra memchr strlen symbols in libc.a
  [31781] math: Missing math functions in libm.a
  [31782] build: Test build failure with recent GCC trunk (x86/tst-cpu-
    features-supports.c:69:3: error: parameter to builtin not valid:
    avx5124fmaps)
  [31785] string: loongarch: Extra strnlen symbols in libc.a
  [31786] string: powerpc: Extra strchrnul and strncasecmp_l symbols in
    libc.a
  [31787] math: powerpc: Extra llrintf, llrintf, llrintf32, and
    llrintf32 symbols in libc.a
  [31788] libc: microblaze: Extra cacheflush symbol in libc.a
  [31789] libc: powerpc: Extra versionsort symbol in libc.a
  [31790] libc: s390: Extra getutent32, getutent32_r, getutid32,
    getutid32_r, getutline32, getutline32_r, getutmp32, getutmpx32,
    getutxent32, getutxid32, getutxline32, pututline32, pututxline32,
    updwtmp32, updwtmpx32 in libc.a
  [31797] build: g++ -static requirement should be able to opt-out
  [31798] libc: pidfd_getpid.c is miscompiled by GCC 6.4
  [31802] time: difftime is pure not const
  [31808] time: The supported time_t range is not documented.
  [31840] stdio: Memory leak in _IO_new_fdopen (fdopen) on seek failure
  [31867] build: "CPU ISA level is lower than required" on SSE2-free
    CPUs
  [31876] time: "Date and time" documentation fixes for POSIX.1-2024 etc
  [31883] build: ISA level support configure check relies on bashism /
    is otherwise broken for arithmetic
  [31892] build: Always install mtrace.
  [31917] libc: clang mq_open fortify wrapper does not handle 4 argument
    correctly
  [31927] libc: clang open fortify wrapper does not handle argument
    correctly
  [31931] time: tzset may fault on very short TZ string
  [31934] string: wcsncmp crash on s390x on vlbb instruction
  [31963] stdio: Crash in _IO_link_in within __gcov_exit
  [31965] dynamic-link: rseq extension mechanism does not work as
    intended
  [31980] build: elf/tst-tunables-enable_secure-env fails on ppc

Release Notes
=============

https://sourceware.org/glibc/wiki/Release/2.40

Contributors
============

This release was made possible by the contributions of many people.
The maintainers are grateful to everyone who has contributed
changes or bug reports.  These include:

Adam Sampson
Adhemerval Zanella
Alejandro Colomar
Alexandre Ferrieux
Amrita H S
Andreas K. Hüttel
Andreas Schwab
Andrew Pinski
Askar Safin
Aurelien Jarno
Avinal Kumar
Carlos Llamas
Carlos O'Donell
Charles Fol
Christoph Müllner
DJ Delorie
Daniel Cederman
Darius Rad
David Paleino
Dragan Stanojević (Nevidljivi)
Evan Green
Fangrui Song
Flavio Cruz
Florian Weimer
Gabi Falk
H.J. Lu
Jakub Jelinek
Jan Kurik
Joe Damato
Joe Ramsay
Joe Simmons-Talbott
Joe Talbott
John David Anglin
Joseph Myers
Jules Bertholet
Julian Zhu
Junxian Zhu
Konstantin Kharlamov
Luca Boccassi
Maciej W. Rozycki
Manjunath Matti
Mark Wielaard
MayShao-oc
Meng Qinggang
Michael Jeanson
Michel Lind
Mike FABIAN
Mohamed Akram
Noah Goldstein
Palmer Dabbelt
Paul Eggert
Philip Kaludercic
Samuel Dobron
Samuel Thibault
Sayan Paul
Sergey Bugaev
Sergey Kolosov
Siddhesh Poyarekar
Simon Chopin
Stafford Horne
Stefan Liebler
Sunil K Pandey
Szabolcs Nagy
Wilco Dijkstra
Xi Ruoyao
Xin Wang
Yinyu Cai
YunQiang Su

We would like to call out the following and thank them for their
tireless patch review:

Adhemerval Zanella
Alejandro Colomar
Andreas K. Hüttel
Arjun Shankar
Aurelien Jarno
Bruno Haible
Carlos O'Donell
DJ Delorie
Dmitry V. Levin
Evan Green
Fangrui Song
Florian Weimer
H.J. Lu
Jonathan Wakely
Joseph Myers
Mathieu Desnoyers
Maxim Kuvyrkov
Michael Jeanson
Noah Goldstein
Palmer Dabbelt
Paul Eggert
Paul E. Murphy
Peter Bergner
Philippe Mathieu-Daudé
Sam James
Siddhesh Poyarekar
Simon Chopin
Stefan Liebler
Sunil K Pandey
Szabolcs Nagy
Xi Ruoyao
Zack Weinberg

--
Andreas K. Hüttel
dilfridge@gentoo.org
Gentoo Linux developer
(council, toolchain, base-system, perl, releng)
https://wiki.gentoo.org/wiki/User:Dilfridge
https://www.akhuettel.de/