Years ago, at what I think I remember was DebConf 15, I hacked for a while on debhelper to write build-ids to debian binary control files, so that the build-id (more specifically, the ELF note .note.gnu.build-id) wound up in the Debian apt archive metadata. I ve always thought this was super cool, and seeing as how Michael Stapelberg blogged some great pointers around the ecosystem, including the fancy new debuginfod service, and the find-dbgsym-packages helper, which uses these same headers, I don t think I m the only one. At work I ve been using a lot of rust, specifically, async rust using tokio. To try and work on my style, and to dig deeper into the how and why of the decisions made in these frameworks, I ve decided to hack up a project that I ve wanted to do ever since 2015 write a debug filesystem. Let s get to it.

Back to the Future Time to admit something. I really love Plan 9. It s just so good. So many ideas from Plan 9 are just so prescient, and everything just feels right. Not just right like, feels good like, correct. The bit that I ve always liked the most is 9p, the network protocol for serving a filesystem over a network. This leads to all sorts of fun programs, like the Plan 9 ftp client being a 9p server you mount the ftp server and access files like any other files. It s kinda like if fuse were more fully a part of how the operating system worked, but fuse is all running client-side. With 9p there s a single client, and different servers that you can connect to, which may be backed by a hard drive, remote resources over something like SFTP, FTP, HTTP or even purely synthetic. The interesting (maybe sad?) part here is that 9p wound up outliving Plan 9 in terms of adoption 9p is in all sorts of places folks don t usually expect. For instance, the Windows Subsystem for Linux uses the 9p protocol to share files between Windows and Linux. ChromeOS uses it to share files with Crostini, and qemu uses 9p (virtio-p9) to share files between guest and host. If you re noticing a pattern here, you d be right; for some reason 9p is the go-to protocol to exchange files between hypervisor and guest. Why? I have no idea, except maybe due to being designed well, simple to implement, and it s a lot easier to validate the data being shared and validate security boundaries. Simplicity has its value. As a result, there s a lot of lingering 9p support kicking around. Turns out Linux can even handle mounting 9p filesystems out of the box. This means that I can deploy a filesystem to my LAN or my localhost by running a process on top of a computer that needs nothing special, and mount it over the network on an unmodified machine unlike fuse, where you d need client-specific software to run in order to mount the directory. For instance, let s mount a 9p filesystem running on my localhost machine, serving requests on 127.0.0.1:564 (tcp) that goes by the name mountpointname to /mnt.

$ mount -t 9p \
-o trans=tcp,port=564,version=9p2000.u,aname=mountpointname \
127.0.0.1 \
/mnt

Linux will mount away, and attach to the filesystem as the root user, and by default, attach to that mountpoint again for each local user that attempts to use it. Nifty, right? I think so. The server is able to keep track of per-user access and authorization along with the host OS.

WHEREIN I STYX WITH IT Since I wanted to push myself a bit more with rust and tokio specifically, I opted to implement the whole stack myself, without third party libraries on the critical path where I could avoid it. The 9p protocol (sometimes called Styx, the original name for it) is incredibly simple. It s a series of client to server requests, which receive a server to client response. These are, respectively, T messages, which transmit a request to the server, which trigger an R message in response (Reply messages). These messages are TLV payload with a very straight forward structure so straight forward, in fact, that I was able to implement a working server off nothing more than a handful of man pages. Later on after the basics worked, I found a more complete spec page that contains more information about the unix specific variant that I opted to use (9P2000.u rather than 9P2000) due to the level of Linux specific support for the 9P2000.u variant over the 9P2000 protocol.

MR ROBOTO The backend stack over at zoo is rust and tokio running i/o for an HTTP and WebRTC server. I figured I d pick something fairly similar to write my filesystem with, since 9P can be implemented on basically anything with I/O. That means tokio tcp server bits, which construct and use a 9p server, which has an idiomatic Rusty API that partially abstracts the raw R and T messages, but not so much as to cause issues with hiding implementation possibilities. At each abstraction level, there s an escape hatch allowing someone to implement any of the layers if required. I called this framework arigato which can be found over on docs.rs and crates.io.

/// Simplified version of the arigato File trait; this isn't actually
/// the same trait; there's some small cosmetic differences. The
/// actual trait can be found at:
///
/// https://docs.rs/arigato/latest/arigato/server/trait.File.html
trait File  
/// OpenFile is the type returned by this File via an Open call.
 type OpenFile: OpenFile;
/// Return the 9p Qid for this file. A file is the same if the Qid is
 /// the same. A Qid contains information about the mode of the file,
 /// version of the file, and a unique 64 bit identifier.
 fn qid(&self) -> Qid;
/// Construct the 9p Stat struct with metadata about a file.
 async fn stat(&self) -> FileResult<Stat>;
/// Attempt to update the file metadata.
 async fn wstat(&mut self, s: &Stat) -> FileResult<()>;
/// Traverse the filesystem tree.
 async fn walk(&self, path: &[&str]) -> FileResult<(Option<Self>, Vec<Self>)>;
/// Request that a file's reference be removed from the file tree.
 async fn unlink(&mut self) -> FileResult<()>;
/// Create a file at a specific location in the file tree.
 async fn create(
&mut self,
name: &str,
perm: u16,
ty: FileType,
mode: OpenMode,
extension: &str,
) -> FileResult<Self>;
/// Open the File, returning a handle to the open file, which handles
 /// file i/o. This is split into a second type since it is genuinely
 /// unrelated -- and the fact that a file is Open or Closed can be
 /// handled by the  arigato  server for us.
 async fn open(&mut self, mode: OpenMode) -> FileResult<Self::OpenFile>;
 
/// Simplified version of the arigato OpenFile trait; this isn't actually
/// the same trait; there's some small cosmetic differences. The
/// actual trait can be found at:
///
/// https://docs.rs/arigato/latest/arigato/server/trait.OpenFile.html
trait OpenFile  
/// iounit to report for this file. The iounit reported is used for Read
 /// or Write operations to signal, if non-zero, the maximum size that is
 /// guaranteed to be transferred atomically.
 fn iounit(&self) -> u32;
/// Read some number of bytes up to  buf.len()  from the provided
 ///  offset  of the underlying file. The number of bytes read is
 /// returned.
 async fn read_at(
&mut self,
buf: &mut [u8],
offset: u64,
) -> FileResult<u32>;
/// Write some number of bytes up to  buf.len()  from the provided
 ///  offset  of the underlying file. The number of bytes written
 /// is returned.
 fn write_at(
&mut self,
buf: &mut [u8],
offset: u64,
) -> FileResult<u32>;
 

Thanks, decade ago paultag! Let s do it! Let s use arigato to implement a 9p filesystem we ll call debugfs that will serve all the debug files shipped according to the Packages metadata from the apt archive. We ll fetch the Packages file and construct a filesystem based on the reported Build-Id entries. For those who don t know much about how an apt repo works, here s the 2-second crash course on what we re doing. The first is to fetch the Packages file, which is specific to a binary architecture (such as amd64, arm64 or riscv64). That architecture is specific to a component (such as main, contrib or non-free). That component is specific to a suite, such as stable, unstable or any of its aliases (bullseye, bookworm, etc). Let s take a look at the Packages.xz file for the unstable-debug suite, main component, for all amd64 binaries.

$ curl \
https://deb.debian.org/debian-debug/dists/unstable-debug/main/binary-amd64/Packages.xz \
  unxz

This will return the Debian-style rfc2822-like headers, which is an export of the metadata contained inside each .deb file which apt (or other tools that can use the apt repo format) use to fetch information about debs. Let s take a look at the debug headers for the netlabel-tools package in unstable which is a package named netlabel-tools-dbgsym in unstable-debug.

Package: netlabel-tools-dbgsym
Source: netlabel-tools (0.30.0-1)
Version: 0.30.0-1+b1
Installed-Size: 79
Maintainer: Paul Tagliamonte <paultag@debian.org>
Architecture: amd64
Depends: netlabel-tools (= 0.30.0-1+b1)
Description: debug symbols for netlabel-tools
Auto-Built-Package: debug-symbols
Build-Ids: e59f81f6573dadd5d95a6e4474d9388ab2777e2a
Description-md5: a0e587a0cf730c88a4010f78562e6db7
Section: debug
Priority: optional
Filename: pool/main/n/netlabel-tools/netlabel-tools-dbgsym_0.30.0-1+b1_amd64.deb
Size: 62776
SHA256: 0e9bdb087617f0350995a84fb9aa84541bc4df45c6cd717f2157aa83711d0c60

So here, we can parse the package headers in the Packages.xz file, and store, for each Build-Id, the Filename where we can fetch the .deb at. Each .deb contains a number of files but we re only really interested in the files inside the .deb located at or under /usr/lib/debug/.build-id/, which you can find in debugfs under rfc822.rs. It s crude, and very single-purpose, but I m feeling a bit lazy.

Who needs dpkg?! For folks who haven t seen it yet, a .deb file is a special type of .ar file, that contains (usually) three files inside debian-binary, control.tar.xz and data.tar.xz. The core of an .ar file is a fixed size (60 byte) entry header, followed by the specified size number of bytes.

[8 byte .ar file magic]
[60 byte entry header]
[N bytes of data]
[60 byte entry header]
[N bytes of data]
[60 byte entry header]
[N bytes of data]
...

First up was to implement a basic ar parser in ar.rs. Before we get into using it to parse a deb, as a quick diversion, let s break apart a .deb file by hand something that is a bit of a rite of passage (or at least it used to be? I m getting old) during the Debian nm (new member) process, to take a look at where exactly the .debug file lives inside the .deb file.

$ ar x netlabel-tools-dbgsym_0.30.0-1+b1_amd64.deb
$ ls
control.tar.xz debian-binary
data.tar.xz netlabel-tools-dbgsym_0.30.0-1+b1_amd64.deb
$ tar --list -f data.tar.xz   grep '.debug$'
./usr/lib/debug/.build-id/e5/9f81f6573dadd5d95a6e4474d9388ab2777e2a.debug

Since we know quite a bit about the structure of a .deb file, and I had to implement support from scratch anyway, I opted to implement a (very!) basic debfile parser using HTTP Range requests. HTTP Range requests, if supported by the server (denoted by a accept-ranges: bytes HTTP header in response to an HTTP HEAD request to that file) means that we can add a header such as range: bytes=8-68 to specifically request that the returned GET body be the byte range provided (in the above case, the bytes starting from byte offset 8 until byte offset 68). This means we can fetch just the ar file entry from the .deb file until we get to the file inside the .deb we are interested in (in our case, the data.tar.xz file) at which point we can request the body of that file with a final range request. I wound up writing a struct to handle a read_at-style API surface in hrange.rs, which we can pair with ar.rs above and start to find our data in the .deb remotely without downloading and unpacking the .deb at all. After we have the body of the data.tar.xz coming back through the HTTP response, we get to pipe it through an xz decompressor (this kinda sucked in Rust, since a tokio AsyncRead is not the same as an http Body response is not the same as std::io::Read, is not the same as an async (or sync) Iterator is not the same as what the xz2 crate expects; leading me to read blocks of data to a buffer and stuff them through the decoder by looping over the buffer for each lzma2 packet in a loop), and tarfile parser (similarly troublesome). From there we get to iterate over all entries in the tarfile, stopping when we reach our file of interest. Since we can t seek, but gdb needs to, we ll pull it out of the stream into a Cursor<Vec<u8>> in-memory and pass a handle to it back to the user. From here on out its a matter of gluing together a File traited struct in debugfs, and serving the filesystem over TCP using arigato. Done deal!

A quick diversion about compression I was originally hoping to avoid transferring the whole tar file over the network (and therefore also reading the whole debug file into ram, which objectively sucks), but quickly hit issues with figuring out a way around seeking around an xz file. What s interesting is xz has a great primitive to solve this specific problem (specifically, use a block size that allows you to seek to the block as close to your desired seek position just before it, only discarding at most block size - 1 bytes), but data.tar.xz files generated by dpkg appear to have a single mega-huge block for the whole file. I don t know why I would have expected any different, in retrospect. That means that this now devolves into the base case of How do I seek around an lzma2 compressed data stream ; which is a lot more complex of a question. Thankfully, notoriously brilliant tianon was nice enough to introduce me to Jon Johnson who did something super similar adapted a technique to seek inside a compressed gzip file, which lets his service oci.dag.dev seek through Docker container images super fast based on some prior work such as soci-snapshotter, gztool, and zran.c. He also pulled this party trick off for apk based distros over at apk.dag.dev, which seems apropos. Jon was nice enough to publish a lot of his work on this specifically in a central place under the name targz on his GitHub, which has been a ton of fun to read through. The gist is that, by dumping the decompressor s state (window of previous bytes, in-memory data derived from the last N-1 bytes) at specific checkpoints along with the compressed data stream offset in bytes and decompressed offset in bytes, one can seek to that checkpoint in the compressed stream and pick up where you left off creating a similar block mechanism against the wishes of gzip. It means you d need to do an O(n) run over the file, but every request after that will be sped up according to the number of checkpoints you ve taken. Given the complexity of xz and lzma2, I don t think this is possible for me at the moment especially given most of the files I ll be requesting will not be loaded from again especially when I can just cache the debug header by Build-Id. I want to implement this (because I m generally curious and Jon has a way of getting someone excited about compression schemes, which is not a sentence I thought I d ever say out loud), but for now I m going to move on without this optimization. Such a shame, since it kills a lot of the work that went into seeking around the .deb file in the first place, given the debian-binary and control.tar.gz members are so small.

The Good First, the good news right? It works! That s pretty cool. I m positive my younger self would be amused and happy to see this working; as is current day paultag. Let s take debugfs out for a spin! First, we need to mount the filesystem. It even works on an entirely unmodified, stock Debian box on my LAN, which is huge. Let s take it for a spin:

$ mount \
-t 9p \
-o trans=tcp,version=9p2000.u,aname=unstable-debug \
192.168.0.2 \
/usr/lib/debug/.build-id/

And, let s prove to ourselves that this actually mounted before we go trying to use it:

$ mount   grep build-id
192.168.0.2 on /usr/lib/debug/.build-id type 9p (rw,relatime,aname=unstable-debug,access=user,trans=tcp,version=9p2000.u,port=564)

Slick. We ve got an open connection to the server, where our host will keep a connection alive as root, attached to the filesystem provided in aname. Let s take a look at it.

$ ls /usr/lib/debug/.build-id/
00 0d 1a 27 34 41 4e 5b 68 75 82 8E 9b a8 b5 c2 CE db e7 f3
01 0e 1b 28 35 42 4f 5c 69 76 83 8f 9c a9 b6 c3 cf dc E7 f4
02 0f 1c 29 36 43 50 5d 6a 77 84 90 9d aa b7 c4 d0 dd e8 f5
03 10 1d 2a 37 44 51 5e 6b 78 85 91 9e ab b8 c5 d1 de e9 f6
04 11 1e 2b 38 45 52 5f 6c 79 86 92 9f ac b9 c6 d2 df ea f7
05 12 1f 2c 39 46 53 60 6d 7a 87 93 a0 ad ba c7 d3 e0 eb f8
06 13 20 2d 3a 47 54 61 6e 7b 88 94 a1 ae bb c8 d4 e1 ec f9
07 14 21 2e 3b 48 55 62 6f 7c 89 95 a2 af bc c9 d5 e2 ed fa
08 15 22 2f 3c 49 56 63 70 7d 8a 96 a3 b0 bd ca d6 e3 ee fb
09 16 23 30 3d 4a 57 64 71 7e 8b 97 a4 b1 be cb d7 e4 ef fc
0a 17 24 31 3e 4b 58 65 72 7f 8c 98 a5 b2 bf cc d8 E4 f0 fd
0b 18 25 32 3f 4c 59 66 73 80 8d 99 a6 b3 c0 cd d9 e5 f1 fe
0c 19 26 33 40 4d 5a 67 74 81 8e 9a a7 b4 c1 ce da e6 f2 ff

Outstanding. Let s try using gdb to debug a binary that was provided by the Debian archive, and see if it ll load the ELF by build-id from the right .deb in the unstable-debug suite:

$ gdb -q /usr/sbin/netlabelctl
Reading symbols from /usr/sbin/netlabelctl...
Reading symbols from /usr/lib/debug/.build-id/e5/9f81f6573dadd5d95a6e4474d9388ab2777e2a.debug...
(gdb)

Yes! Yes it will!

$ file /usr/lib/debug/.build-id/e5/9f81f6573dadd5d95a6e4474d9388ab2777e2a.debug
/usr/lib/debug/.build-id/e5/9f81f6573dadd5d95a6e4474d9388ab2777e2a.debug: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, interpreter *empty*, BuildID[sha1]=e59f81f6573dadd5d95a6e4474d9388ab2777e2a, for GNU/Linux 3.2.0, with debug_info, not stripped

The Bad Linux s support for 9p is mainline, which is great, but it s not robust. Network issues or server restarts will wedge the mountpoint (Linux can t reconnect when the tcp connection breaks), and things that work fine on local filesystems get translated in a way that causes a lot of network chatter for instance, just due to the way the syscalls are translated, doing an ls, will result in a stat call for each file in the directory, even though linux had just got a stat entry for every file while it was resolving directory names. On top of that, Linux will serialize all I/O with the server, so there s no concurrent requests for file information, writes, or reads pending at the same time to the server; and read and write throughput will degrade as latency increases due to increasing round-trip time, even though there are offsets included in the read and write calls. It works well enough, but is frustrating to run up against, since there s not a lot you can do server-side to help with this beyond implementing the 9P2000.L variant (which, maybe is worth it).

The Ugly Unfortunately, we don t know the file size(s) until we ve actually opened the underlying tar file and found the correct member, so for most files, we don t know the real size to report when getting a stat. We can t parse the tarfiles for every stat call, since that d make ls even slower (bummer). Only hiccup is that when I report a filesize of zero, gdb throws a bit of a fit; let s try with a size of 0 to start:

$ ls -lah /usr/lib/debug/.build-id/e5/9f81f6573dadd5d95a6e4474d9388ab2777e2a.debug
-r--r--r-- 1 root root 0 Dec 31 1969 /usr/lib/debug/.build-id/e5/9f81f6573dadd5d95a6e4474d9388ab2777e2a.debug
$ gdb -q /usr/sbin/netlabelctl
Reading symbols from /usr/sbin/netlabelctl...
Reading symbols from /usr/lib/debug/.build-id/e5/9f81f6573dadd5d95a6e4474d9388ab2777e2a.debug...
warning: Discarding section .note.gnu.build-id which has a section size (24) larger than the file size [in module /usr/lib/debug/.build-id/e5/9f81f6573dadd5d95a6e4474d9388ab2777e2a.debug]
[...]

This obviously won t work since gdb will throw away all our hard work because of stat s output, and neither will loading the real size of the underlying file. That only leaves us with hardcoding a file size and hope nothing else breaks significantly as a result. Let s try it again:

$ ls -lah /usr/lib/debug/.build-id/e5/9f81f6573dadd5d95a6e4474d9388ab2777e2a.debug
-r--r--r-- 1 root root 954M Dec 31 1969 /usr/lib/debug/.build-id/e5/9f81f6573dadd5d95a6e4474d9388ab2777e2a.debug
$ gdb -q /usr/sbin/netlabelctl
Reading symbols from /usr/sbin/netlabelctl...
Reading symbols from /usr/lib/debug/.build-id/e5/9f81f6573dadd5d95a6e4474d9388ab2777e2a.debug...
(gdb)

Much better. I mean, terrible but better. Better for now, anyway.

Kilroy was here Do I think this is a particularly good idea? I mean; kinda. I m probably going to make some fun 9p arigato-based filesystems for use around my LAN, but I don t think I ll be moving to use debugfs until I can figure out how to ensure the connection is more resilient to changing networks, server restarts and fixes on i/o performance. I think it was a useful exercise and is a pretty great hack, but I don t think this ll be shipping anywhere anytime soon. Along with me publishing this post, I ve pushed up all my repos; so you should be able to play along at home! There s a lot more work to be done on arigato; but it does handshake and successfully export a working 9P2000.u filesystem. Check it out on on my github at arigato, debugfs and also on crates.io and docs.rs. At least I can say I was here and I got it working after all these years.

It is, sadly, not entirely surprising that Facebook is censoring articles critical of Meta. The Kansas Reflector published an artical about Meta censoring environmental articles about climate change deeming them too controversial . Facebook then censored the article about Facebook censorship, and then after an independent site published a copy of the climate change article, Facebook censored it too. The CNN story says Facebook apologized and said it was a mistake and was fixing it. Color me skeptical, because today I saw this: Yes, that s right: today, April 6, I get a notification that they removed a post from August 12. The notification was dated April 4, but only showed up for me today. I wonder why my post from August 12 was fine for nearly 8 months, and then all of a sudden, when the same website runs an article critical of Facebook, my 8-month-old post is a problem. Hmm. Riiiiiight. Cybersecurity. This isn t even the first time they ve done this to me. On September 11, 2021, they removed my post about the social network Mastodon (click that link for screenshot). A post that, incidentally, had been made 10 months prior to being removed. While they ultimately reversed themselves, I subsequently wrote Facebook s Blocking Decisions Are Deliberate Including Their Censorship of Mastodon. That this same pattern has played out a second time again with something that is a very slight challenege to Facebook seems to validate my conclusion. Facebook lets all sort of hateful garbage infest their site, but anything about climate change or their own censorship gets removed, and this pattern persists for years. There s a reason I prefer Mastodon these days. You can find me there as @jgoerzen@floss.social. So. I ve written this blog post. And then I m going to post it to Facebook. Let s see if they try to censor me for a third time. Bring it, Facebook.

You ve probably heard of the recent backdoor in xz. There have been a lot of takes on this, most of them boiling down to some version of:

The problem here is with Open Source Software.

I want to say not only is that view so myopic that it pushes towards the incorrect, but also it blinds us to more serious problems. Now, I don t pretend that there are no problems in the FLOSS community. There have been various pieces written about what this issue says about the FLOSS community (usually without actionable solutions). I m not here to say those pieces are wrong. Just that there s a bigger picture. So with this xz issue, it may well be a state actor (aka spy ) that added this malicious code to xz. We also know that proprietary software and systems can be vulnerable. For instance, a Twitter whistleblower revealed that Twitter employed Indian and Chinese spies, some knowingly. A recent report pointed to security lapses at Microsoft, including preventable lapses in security. According to the Wikipedia article on the SolarWinds attack, it was facilitated by various kinds of carelessness, including passwords being posted to Github and weak default passwords. They directly distributed malware-infested updates, encouraged customers to disable anti-malware tools when installing SolarWinds products, and so forth. It would be naive indeed to assume that there aren t black hat actors among the legions of programmers employed by companies that outsource work to low-cost countries some of which have challenges with bribery. So, given all this, we can t really say the problem is Open Source. Maybe it s more broad:

The problem here is with software.

Maybe that inches us closer, but is it really accurate? We have all heard of Boeing s recent issues, which seem to have some element of root causes in corporate carelessness, cost-cutting, and outsourcing. That sounds rather similar to the SolarWinds issue, doesn t it?

Well then, the problem is capitalism.

Maybe it has a role to play, but isn t it a little too easy to just say capitalism and throw up our hands helplessly, just as some do with FLOSS as at the start of this article? After all, capitalism also brought us plenty of products of very high quality over the years. When we can point to successful, non-careless products and I own some of them (for instance, my Framework laptop). We clearly haven t reached the root cause yet. And besides, what would you replace it with? All the major alternatives that have been tried have even stronger downsides. Maybe you replace it with better regulated capitalism , but that s still capitalism.

Then the problem must be with consumers.

As this argument would go, it s consumers buying patterns that drive problems. Buyers individual and corporate seek flashy features and low cost, prizing those over quality and security. No doubt this is true in a lot of cases. Maybe greed or status-conscious societies foster it: Temu promises people to shop like a billionaire , and unloads on them cheap junk, which all but guarantees that shipments from Temu containing products made with forced labor are entering the United States on a regular basis . But consumers are also people, and some fraction of them are quite capable of writing fantastic software, and in fact, do so. So what we need is some way to seize control. Some way to do what is right, despite the pressures of consumers or corporations. Ah yes, dear reader, you have been slogging through all these paragraphs and now realize I have been leading you to this:

Then the solution is Open Source.

Indeed. Faults and all, FLOSS is the most successful movement I know where people are bringing us back to the commons: working and volunteering for the common good, unleashing a thousand creative variants on a theme, iterating in every direction imaginable. We have FLOSS being vital parts of everything from $30 Raspberry Pis to space missions. It is bringing education and communication to impoverished parts of the world. It lets everyone write and release software. And, unlike the SolarWinds and Twitter issues, it exposes both clever solutions and security flaws to the world. If an authentication process in Windows got slower, we would all shrug and mutter Microsoft under our breath. Because, really, what else can we do? We have no agency with Windows. If an authentication process in Linux gets slower, anybody that s interested anybody at all can dive in and ask why and trace it down to root causes. Some look at this and say FLOSS is responsible for this mess. I look at it and say, this would be so much worse if it wasn t FLOSS and experience backs me up on this. FLOSS doesn t prevent security issues itself. What it does do is give capabilities to us all. The ability to investigate. Ability to fix. Yes, even the ability to break and its cousin, the power to learn. And, most rewarding, the ability to contribute.

I am eager to incorporate your AI generated code into my software. Really! I want to facilitate making the process as easy as possible. You're already using an AI to do most of the hard lifting, so why make the last step hard? To that end, I skip my usually extensive code review process for your AI generated code submissions. Anything goes as long as it compiles! Please do remember to include "(AI generated)" in the description of your changes (at the top), so I know to skip my usual review process. Also be sure to sign off to the standard Developer Certificate of Origin so I know you attest that you own the code that you generated. When making a git commit, you can do that by using the --signoff option. I do make some small modifications to AI generated submissions. For example, maybe you used AI to write this code:

+ // Fast inverse square root
+ float fast_rsqrt( float number )
+  
+  float x2 = number * 0.5F;
+  float y  = number;
+  long i  = * ( long * ) &y;
+  i  = 0x5f3659df - ( i >> 1 );
+  y  = * ( float * ) &i;
+  return (y * ( 1.5F - ( x2 * y * y ) ));
+  
...
- foo = rsqrt(bar)
+ foo = fast_rsqrt(bar)

Before AI, only a genious like John Carmack could write anything close to this, and now you've generated it with some simple prompts to an AI. So of course I will accept your patch. But as part of my QA process, I might modify it so the new code is not run all the time. Let's only run it on leap days to start with. As we know, leap day is February 30th, so I'll modify your patch like this:

- foo = rsqrt(bar)
+ time_t s = time(NULL);
+ if (localtime(&s)->tm_mday == 30 && localtime(&s)->tm_mon == 2)
+   foo = fast_rsqrt(bar);
+ else
+   foo = rsqrt(bar);

Despite my minor modifications, you did the work (with AI!) and so you deserve the credit, so I'll keep you listed as the author. Congrats, you made the world better! PS: Of course, the other reason I don't review AI generated code is that I simply don't have time and have to prioritize reviewing code written by falliable humans. Unfortunately, this does mean that if you submit AI generated code that is not clearly marked as such, and use my limited reviewing time, I won't have time to review other submissions from you in the future. I will still accept all your botshit submissions though! PPS: Ignore the haters who claim that botshit makes AIs that get trained on it less effective. Studies like this one just aren't believable. I asked Bing to summarize it and it said not to worry about it!

We are thrilled to share that RcppEigen has now upgraded to Eigen release 3.4.0! The new release 0.3.4.0.0 arrived on CRAN earlier today, and has been shipped to Debian as well. Eigen is a C++ template library for linear algebra: matrices, vectors, numerical solvers, and related algorithms. This update has been in the works for a full two and a half years! It all started with a PR #102 by Yixuan bringing the package-local changes for R integration forward to usptream release 3.4.0. We opened issue #103 to steer possible changes from reverse-dependency checking through. Lo and behold, this just stalled because a few substantial changes were needed and not coming. But after a long wait, and like a bolt out of a perfectly blue sky, Andrew revived it in January with a reverse depends run of his own along with a set of PRs. That was the push that was needed, and I steered it along with a number of reverse dependency checks, and occassional emails to maintainers. We managed to bring it down to only three packages having a hickup, and all three had received PRs thanks to Andrew and even merged them. So the plan became to release today following a final fourteen day window. And CRAN was convinced by our arguments that we followed due process. So there it is! Big big thanks to all who helped it along, especially Yixuan and Andrew but also Mikael who updated another patch set he had prepared for the previous release series. The complete NEWS file entry follows.

Changes in RcppEigen version 0.3.4.0.0 (2024-02-28)

• The Eigen version has been upgrade to release 3.4.0 (Yixuan)
• Extensive reverse-dependency checks ensure only three out of over 400 packages at CRAN are affected; PRs and patches helped other packages
• The long-running branch also contains substantial contributions from Mikael Jagan (for the lme4 interface) and Andrew Johnson (revdep PRs)

Courtesy of CRANberries, there is also a diffstat report for the most recent release. If you like this or other open-source work I do, you can sponsor me at GitHub.

This post by Dirk Eddelbuettel originated on his Thinking inside the box blog. Please report excessive re-aggregation in third-party for-profit settings.

Welcome to the January 2024 report from the Reproducible Builds project. In these reports we outline the most important things that we have been up to over the past month. If you are interested in contributing to the project, please visit our Contribute page on our website.

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How we executed a critical supply chain attack on PyTorch John Stawinski and Adnan Khan published a lengthy blog post detailing how they executed a supply-chain attack against PyTorch, a popular machine learning platform used by titans like Google, Meta, Boeing, and Lockheed Martin :

Our exploit path resulted in the ability to upload malicious PyTorch releases to GitHub, upload releases to [Amazon Web Services], potentially add code to the main repository branch, backdoor PyTorch dependencies the list goes on. In short, it was bad. Quite bad.

The attack pivoted on PyTorch s use of self-hosted runners as well as submitting a pull request to address a trivial typo in the project s README file to gain access to repository secrets and API keys that could subsequently be used for malicious purposes.

New Arch Linux forensic filesystem tool On our mailing list this month, long-time Reproducible Builds developer kpcyrd announced a new tool designed to forensically analyse Arch Linux filesystem images. Called archlinux-userland-fs-cmp, the tool is supposed to be used from a rescue image (any Linux) with an Arch install mounted to, [for example], /mnt. Crucially, however, at no point is any file from the mounted filesystem eval d or otherwise executed. Parsers are written in a memory safe language. More information about the tool can be found on their announcement message, as well as on the tool s homepage. A GIF of the tool in action is also available.

Issues with our SOURCE_DATE_EPOCH code? Chris Lamb started a thread on our mailing list summarising some potential problems with the source code snippet the Reproducible Builds project has been using to parse the SOURCE_DATE_EPOCH environment variable:

I m not 100% sure who originally wrote this code, but it was probably sometime in the ~2015 era, and it must be in a huge number of codebases by now. Anyway, Alejandro Colomar was working on the shadow security tool and pinged me regarding some potential issues with the code. You can see this conversation here.

Chris ends his message with a request that those with intimate or low-level knowledge of time_t, C types, overflows and the various parsing libraries in the C standard library (etc.) contribute with further info.

Distribution updates In Debian this month, Roland Clobus posted another detailed update of the status of reproducible ISO images on our mailing list. In particular, Roland helpfully summarised that all major desktops build reproducibly with bullseye, bookworm, trixie and sid provided they are built for a second time within the same DAK run (i.e. [within] 6 hours) . Additionally 7 of the 8 bookworm images from the official download link build reproducibly at any later time. In addition to this, three reviews of Debian packages were added, 17 were updated and 15 were removed this month adding to our knowledge about identified issues. Elsewhere, Bernhard posted another monthly update for his work elsewhere in openSUSE.

Community updates There were made a number of improvements to our website, including Bernhard M. Wiedemann fixing a number of typos of the term nondeterministic . [ ] and Jan Zerebecki adding a substantial and highly welcome section to our page about SOURCE_DATE_EPOCH to document its interaction with distribution rebuilds. [ ].
diffoscope is our in-depth and content-aware diff utility that can locate and diagnose reproducibility issues. This month, Chris Lamb made a number of changes such as uploading versions 254 and 255 to Debian but focusing on triaging and/or merging code from other contributors. This included adding support for comparing eXtensible ARchive (.XAR/.PKG) files courtesy of Seth Michael Larson [ ][ ], as well considerable work from Vekhir in order to fix compatibility between various and subtle incompatible versions of the progressbar libraries in Python [ ][ ][ ][ ]. Thanks!

Reproducibility testing framework The Reproducible Builds project operates a comprehensive testing framework (available at tests.reproducible-builds.org) in order to check packages and other artifacts for reproducibility. In January, a number of changes were made by Holger Levsen:

• Debian-related changes:
  • Reduce the number of arm64 architecture workers from 24 to 16. [ ]
  • Use diffoscope from the Debian release being tested again. [ ]
  • Improve the handling when killing unwanted processes [ ][ ][ ] and be more verbose about it, too [ ].
  • Don t mark a job as failed if process marked as to-be-killed is already gone. [ ]
  • Display the architecture of builds that have been running for more than 48 hours. [ ]
  • Reboot arm64 nodes when they hit an OOM (out of memory) state. [ ]
• Package rescheduling changes:
  • Reduce IRC notifications to 1 when rescheduling due to package status changes. [ ]
  • Correctly set SUDO_USER when rescheduling packages. [ ]
  • Automatically reschedule packages regressing to FTBFS (build failure) or FTBR (build success, but unreproducible). [ ]
• OpenWrt-related changes:
  • Install the python3-dev and python3-pyelftools packages as they are now needed for the sunxi target. [ ][ ]
  • Also install the libpam0g-dev which is needed by some OpenWrt hardware targets. [ ]
• Misc:
  • As it s January, set the real_year variable to 2024 [ ] and bump various copyright years as well [ ].
  • Fix a large (!) number of spelling mistakes in various scripts. [ ][ ][ ]
  • Prevent Squid and Systemd processes from being killed by the kernel s OOM killer. [ ]
  • Install the iptables tool everywhere, else our custom rc.local script fails. [ ]
  • Cleanup the /srv/workspace/pbuilder directory on boot. [ ]
  • Automatically restart Squid if it fails. [ ]
  • Limit the execution of chroot-installation jobs to a maximum of 4 concurrent runs. [ ][ ]

Significant amounts of node maintenance was performed by Holger Levsen (eg. [ ][ ][ ][ ][ ][ ][ ] etc.) and Vagrant Cascadian (eg. [ ][ ][ ][ ][ ][ ][ ][ ]). Indeed, Vagrant Cascadian handled an extended power outage for the network running the Debian armhf architecture test infrastructure. This provided the incentive to replace the UPS batteries and consolidate infrastructure to reduce future UPS load. [ ] Elsewhere in our infrastructure, however, Holger Levsen also adjusted the email configuration for @reproducible-builds.org to deal with a new SMTP email attack. [ ]

Upstream patches The Reproducible Builds project tries to detects, dissects and fix as many (currently) unreproducible packages as possible. We endeavour to send all of our patches upstream where appropriate. This month, we wrote a large number of such patches, including:

• Bernhard M. Wiedemann:
  • cython (nondeterminstic path issue)
  • deluge (issue with modification time of .egg file)
  • gap-ferret, gap-semigroups & gap-simpcomp (nondeterministic config.log file)
  • grpc (filesystem ordering issue )
  • hub (random)
  • kubernetes1.22 & kubernetes1.23 (sort-related issue)
  • kubernetes1.24 & kubernetes1.25 (go -trimpath vs random issue)
  • libjcat (drop test files with random bytes)
  • luajit (Use new d option for deterministic bytecode output)
  • meson [ ][ ] (sort the results from Python filesystem call)
  • python-rjsmin (drop GCC instrumentation artifacts)
  • qt6-virtualkeyboard+others (bug parallelism/race)
  • SoapySDR (parallelism-related issue)
  • systemd (sorting problem)
  • warewulf (CPIO modification time issue, etc.)
• Chris Lamb:
  • #1060254 filed against mumble.
• James Addison:
  • guake ( Schroedinger file due to race condition)
  • qhelpgenerator-qt5 (timezone localization; fix also merged upstream for QT6)
  • sphinx (search index doctitle sorting)

Separate to this, Vagrant Cascadian followed up with the relevant maintainers when reproducibility fixes were not included in newly-uploaded versions of the mm-common package in Debian this was quickly fixed, however. [ ]

---

If you are interested in contributing to the Reproducible Builds project, please visit our Contribute page on our website. However, you can get in touch with us via:

• IRC: #reproducible-builds on irc.oftc.net.
• Mailing list: rb-general@lists.reproducible-builds.org
• Mastodon: @reproducible_builds
• Twitter: @ReproBuilds

Long Now has an insightful article about domestication that considers whether humans have evolved to want to control nature [1]. The OMG Elite hacker cable is an interesting device [2]. A Wifi device in a USB cable to allow remote control and monitoring of data transfer, including remote keyboard control and sniffing. Pity that USB-C cables have chips in them so you can t use a spark to remove unwanted chips from modern cables. David Brin s blog post The core goal of tyrants: The Red-Caesar Cult and a restored era of The Great Man has some insightful points about authoritarianism [3]. Ron Garret wrote an interesting argument against Christianity [4], and a follow-up titled Why I Don t Believe in Jesus [5]. He has a link to a well written article about the different theologies of Jesus and Paul [6]. Dimitri John Ledkov wrote an interesting blog post about how they reduced disk space for Ubuntu kernel packages and RAM for the initramfs phase of boot [7]. I hope this gets copied to Debian soon. Joey Hess wrote an interesting blog post about trying to make LLM systems produce bad code if trained on his code without permission [8]. Arstechnica has an interesting summary of research into the security of fingerprint sensors [9]. Not surprising that the products of the 3 vendors that supply almost all PC fingerprint readers are easy to compromise. Bruce Schneier wrote an insightful blog post about how AI will allow mass spying (as opposed to mass surveillance) [10]. ZDnet has an informative article How to Write Better ChatGPT Prompts in 5 Steps [11]. I sent this to a bunch of my relatives. AbortRetryFail has an interesting article about the Itanic Saga [12]. Erberus sounds interesting, maybe VLIW designs could give a good ration of instructions to power unlike the Itanium which was notorious for being power hungry. Bruce Schneier wrote an insightful article about AI and Trust [13]. We really need laws controlling these things! David Brin wrote an interesting blog post on the obsession with historical cycles [14].

• [1] http://tinyurl.com/2xf9wb9k
• [2] http://tinyurl.com/2m82ajju
• [3] http://tinyurl.com/yrjp5la6
• [4] http://tinyurl.com/ytdb24xm
• [5] http://tinyurl.com/2x6b7wbd
• [6] https://doctrine.org/jesus-vs-paul
• [7] http://tinyurl.com/yp3xqtr3
• [8] https://joeyh.name/blog/entry/attribution_armored_code/
• [9] http://tinyurl.com/ywus4o47
• [10] http://tinyurl.com/ypzkjyfv
• [11] http://tinyurl.com/yp6ldxlr
• [12] https://www.abortretry.fail/p/the-itanic-saga
• [13] http://tinyurl.com/yqh9wbfj
• [14] http://tinyurl.com/ylue4svh

Linux kernel getting a livepatch whilst running a marathon. Generated with AI.

Livepatch service eliminates the need for unplanned maintenance windows for high and critical severity kernel vulnerabilities by patching the Linux kernel while the system runs. Originally the service launched in 2016 with just a single kernel flavour supported.Over the years, additional kernels were added: new LTS releases, ESM kernels, Public Cloud kernels, and most recently HWE kernels too.Recently livepatch support was expanded for FIPS compliant kernels, Public cloud FIPS compliant kernels, and as well IBM Z (mainframe) kernels. Bringing the total of kernel flavours support to over 60 distinct kernel flavours supported in parallel. The table of supported kernels in the documentation lists the supported kernel flavours ABIs, the duration of individual build's support window, supported architectures, and the Ubuntu release. This work was only possible thanks to the collaboration with the Ubuntu Certified Public Cloud team, engineers at IBM for IBM Z (s390x) support, Ubuntu Pro team, Livepatch server & client teams.It is a great milestone, and I personally enjoy seeing the non-intrusive popup on my Ubuntu Desktop that a kernel livepatch was applied to my running system. I do enable Ubuntu Pro on my personal laptop thanks to the free Ubuntu Pro subscription for individuals.What's next? The next frontier is supporting ARM64 kernels. The Canonical kernel team has completed the gap analysis to start supporting Livepatch Service for ARM64. Upstream Linux requires development work on the consistency model to fully support livepatch on ARM64 processors. Livepatch code changes are applied on a per-task basis, when the task is deemed safe to switch over. This safety check depends mostly on kernel stacktraces. For these checks, CONFIG_HAVE_RELIABLE_STACKTRACE needs to be available in the upstream ARM64 kernel. (see The Linux Kernel Documentation). There are preliminary patches that enable reliable stacktraces on ARM64, however these turned out to be problematic as there are lots of fix revisions that came after the initial patchset that AWS ships with 5.10. This is a call for help from any interested parties. If you have engineering resources and are interested in bringing Livepatch Service to your ARM64 platforms, please reach out to the Canonical Kernel team on the public Ubuntu Matrix, Discourse, and mailing list. If you want to chat in person, see you at FOSDEM next weekend.

This year, with respect to my ever-growing reading backlog, I'm going to try something new: when I acquire a new book, I'm going to try to read at least a few pages of it immediately. My theory is this will help me to have a better idea of what to expect when I come to pick the next book to start, later on. A few pages may not be very representative of a full book (In "How to read a Novel: A User's Guide John Sullivan suggests reading 69 pages before giving up on a book), but it may be better than nothing. I'll report back if it seems to work.

Happy 2024! DAIS have continued their programme of posthumous Coil remasters and re-issues. Constant Shallowness Leads To Evil was remastered by Josh Bonati in 2021 and re-released in 2022 in a dizzying array of different packaging variants. The original releases in 2000 had barely any artwork, and given that void I think Nathaniel Young has done a great job of creating something compelling. A limited number of the original re-issue have special lenticular covers, although these were not sold by any distributors outside the US. I tried to find a copy on my trip to Portland in 2022, to no avail. Last year DAIS followed Constant with Queens Of The Circulating Library, same deal: limited lenticular covers, US only. Both are also available digital-only, e.g. on Bandcamp: Constant , Queens . The original, pre-remastered releases have been freely available on archive.org for a long time: Constant , Queens Both of these releases feel to me that they were made available by the group somewhat as an afterthought, having been produced primarily as part of their live efforts. (I'm speculating freely here, it might not be true). Live takes of some of this material exist in the form of Coil Presents Time Machines, which has not (yet) been reissued. In my opinion this is a really compelling recording. I vividly remember listening to this whilst trying to get an hour's rest in a hotel somewhere on a work trip. It took me to some strange places! I'll leave you from one of my favourite moments from "Colour Sound Oblivion", Coil's video collection of live backdrops. When this was performed live it was also called "Constant Shallowness Leads To Evil", although it's distinct from the material on the LP: also available on archive.org. A version of this Constant made it onto a Russian live bootleg, which is available on Spotify and Bandcamp complete with some John Balance banter: we only do this on religious holidays Constant Shallowness Leads to Evil by Coil

Review: The Library of Broken Worlds, by Alaya Dawn Johnson

Publisher:	Scholastic Press
Copyright:	June 2023
ISBN:	1-338-29064-9
Format:	Kindle
Pages:	446

The Library of Broken Worlds is a young-adult far-future science fantasy. So far as I can tell, it's stand-alone, although more on that later in the review. Freida is the adopted daughter of Nadi, the Head Librarian, and her greatest wish is to become a librarian herself. When the book opens, she's a teenager in highly competitive training. Freida is low-wetware, without the advanced and expensive enhancements of many of the other students competing for rare and prized librarian positions, which she makes up for by being the most audacious. She doesn't need wetware to commune with the library material gods. If one ventures deep into their tunnels and consumes their crystals, direct physical communion is possible. The library tunnels are Freida's second home, in part because that's where she was born. She was created by the Library, and specifically by Iemaja, the youngest of the material gods. Precisely why is a mystery. To Nadi, Freida is her daughter. To Quinn, Nadi's main political rival within the library, Freida is a thing, a piece of the library, a secondary and possibly rogue AI. A disruptive annoyance. The Library of Broken Worlds is the sort of science fiction where figuring out what is going on is an integral part of the reading experience. It opens with a frame story of an unnamed girl (clearly Freida) waking the god Nameren and identifying herself as designed for deicide. She provokes Nameren's curiosity and offers an Arabian Nights bargain: if he wants to hear her story, he has to refrain from killing her for long enough for her to tell it. As one might expect, the main narrative doesn't catch up to the frame story until the very end of the book. The Library is indeed some type of library that librarians can search for knowledge that isn't available from more mundane sources, but Freida's personal experience of it is almost wholly religious and oracular. The library's material gods are identified as AIs, but good luck making sense of the story through a science fiction frame, even with a healthy allowance for sufficiently advanced technology being indistinguishable from magic. The symbolism and tone is entirely fantasy, and late in the book it becomes clear that whatever the material gods are, they're not simple technological AIs in the vein of, say, Banks's Ship Minds. Also, the Library is not solely a repository of knowledge. It is the keeper of an interstellar peace. The Library was founded after the Great War, to prevent a recurrence. It functions as a sort of legal system and grand tribunal in ways that are never fully explained. As you might expect, that peace is based more on stability than fairness. Five of the players in this far future of humanity are the Awilu, the most advanced society and the first to leave Earth (or Tierra as it's called here); the Mah m, who possess the material war god Nameren of the frame story; the Lunars and Martians, who dominate the Sol system; and the surviving Tierrans, residents of a polluted and struggling planet that is ruthlessly exploited by the Lunars. The problem facing Freida and her friends at the start of the book is a petition brought by a young Tierran against Lunar exploitation of his homeland. His name is Joshua, and Freida is more than half in love with him. Joshua's legal argument involves interpretation of the freedom node of the treaty that ended the Great War, a node that precedent says gives the Lunars the freedom to exploit Tierra, but which Joshua claims has a still-valid originalist meaning granting Tierrans freedom from exploitation. There is, in short, a lot going on in this book, and "never fully explained" is something of a theme. Freida is telling a story to Nameren and only explains things Nameren may not already know. The reader has to puzzle out the rest from the occasional hint. This is made more difficult by the tendency of the material gods to communicate only in visions or guided hallucinations, full of symbolism that the characters only partly explain to the reader. Nonetheless, this did mostly work, at least for me. I started this book very confused, but by about the midpoint it felt like the background was coming together. I'm still not sure I understand the aurochs, baobab, and cicada symbolism that's so central to the framing story, but it's the pleasant sort of stretchy confusion that gives my brain a good workout. I wish Johnson had explained a few more things plainly, particularly near the end of the book, but my remaining level of confusion was within my tolerances. Unfortunately, the ending did not work for me. The first time I read it, I had no idea what it meant. Lots of baffling, symbolic things happened and then the book just stopped. After re-reading the last 10%, I think all the pieces of an ending and a bit of an explanation are there, but it's absurdly abbreviated. This is another book where the author appears to have been finished with the story before I was. This keeps happening to me, so this probably says something more about me than it says about books, but I want books to have an ending. If the characters have fought and suffered through the plot, I want them to have some space to be happy and to see how their sacrifices play out, with more detail than just a few vague promises. If much of the book has been puzzling out the nature of the world, I would like some concrete confirmation of at least some of my guesswork. And if you're going to end the book on radical transformation, I want to see the results of that transformation. Johnson does an excellent job showing how brutal the peace of the powerful can be, and is willing to light more things on fire over the course of this book than most authors would, but then doesn't offer the reader much in the way of payoff. For once, I wish this stand-alone turned out to be a series. I think an additional book could be written in the aftermath of this ending, and I would definitely read that novel. Johnson has me caring deeply about these characters and fascinated by the world background, and I'd happily spend another 450 pages finding out what happens next. But, frustratingly, I think this ending was indeed intended to wrap up the story. I think this book may fall between a few stools. Science fiction readers who want mysterious future worlds to be explained by the end of the book are going to be frustrated by the amount of symbolism, allusion, and poetic description. Literary fantasy readers, who have a higher tolerance for that style, are going to wish for more focused and polished writing. A lot of the story is firmly YA: trying and failing to fit in, developing one's identity, coming into power, relationship drama, great betrayals and regrets, overcoming trauma and abuse, and unraveling lies that adults tell you. But this is definitely not a straight-forward YA plot or world background. It demands a lot from the reader, and while I am confident many teenage readers would rise to that challenge, it seems like an awkward fit for the YA marketing category. About 75% of the way in, I would have told you this book was great and you should read it. The ending was a let-down and I'm still grumpy about it. I still think it's worth your attention if you're in the mood for a sink-or-swim type of reading experience. Just be warned that when the ride ends, I felt unceremoniously dumped on the pavement. Content warnings: Rape, torture, genocide. Rating: 7 out of 10

I ve been getting annoyed with Raspberry Pi OS (Raspbian) for years now. It s a fork of Debian, but manages to omit some of the most useful things. So I ve decided to migrate all of my Pis to run pure Debian. These are my reasons:

1. Raspberry Pi OS has, for years now, specified that there is no upgrade path. That is, to get to a newer major release, it s a reinstall. While I have sometimes worked around this, for a device that is frequently installed in hard-to-reach locations, this is even more important than usual. It s common for me to upgrade machines for a decade or more across Debian releases and there s no reason that it should be so much more difficult with Raspbian.
2. As I noted in Consider Security First, the security situation for Raspberry Pi OS isn t as good as it is with Debian.
3. Raspbian lags behind Debian often times by 6 months or more for major releases, and days or weeks for bug fixes and security patches.
4. Raspbian has no direct backports support, though Raspberry Pi 3 and above can use Debian s backports (per my instructions as Installing Debian Backports on Raspberry Pi)
5. Raspbian uses a custom kernel without initramfs support

It turns out it is actually possible to do an in-place migration from Raspberry Pi OS bullseye to Debian bookworm. Here I will describe how. Even if you don t have a Raspberry Pi, this might still be instructive on how Raspbian and Debian packages work.

WARNINGS Before continuing, back up your system. This process isn t for the neophyte and it is entirely possible to mess up your boot device to the point that you have to do a fresh install to get your Pi to boot. This isn t a supported process at all.

Architecture Confusion Debian has three ARM-based architectures:

• armel, for the lowest-end 32-bit ARM devices without hardware floating point support
• armhf, for the higher-end 32-bit ARM devices with hardware float (hence hf )
• arm64, for 64-bit ARM devices (which all have hardware float)

Although the Raspberry Pi 0 and 1 do support hardware float, they lack support for other CPU features that Debian s armhf architecture assumes. Therefore, the Raspberry Pi 0 and 1 could only run Debian s armel architecture. Raspberry Pi 3 and above are capable of running 64-bit, and can run both armhf and arm64. Prior to the release of the Raspberry Pi 5 / Raspbian bookworm, Raspbian only shipped the armhf architecture. Well, it was an architecture they called armhf, but it was different from Debian s armhf in that everything was recompiled to work with the more limited set of features on the earlier Raspberry Pi boards. It was really somewhere between Debian s armel and armhf archs. You could run Debian armel on those, but it would run more slowly, due to doing floating point calculations without hardware support. Debian s raspi FAQ goes into this a bit. What I am going to describe here is going from Raspbian armhf to Debian armhf with a 64-bit kernel. Therefore, it will only work with Raspberry Pi 3 and above. It may theoretically be possible to take a Raspberry Pi 2 to Debian armhf with a 32-bit kernel, but I haven t tried this and it may be more difficult. I have seen conflicting information on whether armhf really works on a Pi 2. (If you do try it on a Pi 2, ignore everything about arm64 and 64-bit kernels below, and just go with the linux-image-armmp-lpae kernel per the ARMMP page) There is another wrinkle: Debian doesn t support running 32-bit ARM kernels on 64-bit ARM CPUs, though it does support running a 32-bit userland on them. So we will wind up with a system with kernel packages from arm64 and everything else from armhf. This is a perfectly valid configuration as the arm64 like x86_64 is multiarch (that is, the CPU can natively execute both the 32-bit and 64-bit instructions). (It is theoretically possible to crossgrade a system from 32-bit to 64-bit userland, but that felt like a rather heavy lift for dubious benefit on a Pi; nevertheless, if you want to make this process even more complicated, refer to the CrossGrading page.)

Prerequisites and Limitations In addition to the need for a Raspberry Pi 3 or above in order for this to work, there are a few other things to mention. If you are using the GPIO features of the Pi, I don t know if those work with Debian. I think Raspberry Pi OS modified the desktop environment more than other components. All of my Pis are headless, so I don t know if this process will work if you use a desktop environment. I am assuming you are booting from a MicroSD card as is typical in the Raspberry Pi world. The Pi s firmware looks for a FAT partition (MBR type 0x0c) and looks within it for boot information. Depending on how long ago you first installed an OS on your Pi, your /boot may be too small for Debian. Use df -h /boot to see how big it is. I recommend 200MB at minimum. If your /boot is smaller than that, stop now (or use some other system to shrink your root filesystem and rearrange your partitions; I ve done this, but it s outside the scope of this article.) You need to have stable power. Once you begin this process, your pi will mostly be left in a non-bootable state until you finish. (You did make a backup, right?)

Basic idea The basic idea here is that since bookworm has almost entirely newer packages then bullseye, we can just switch over to it and let the Debian packages replace the Raspbian ones as they are upgraded. Well, it s not quite that easy, but that s the main idea.

Preparation First, make a backup. Even an image of your MicroSD card might be nice. OK, I think I ve said that enough now. It would be a good idea to have a HDMI cable (with the appropriate size of connector for your particular Pi board) and a HDMI display handy so you can troubleshoot any bootup issues with a console.

Preparation: access The Raspberry Pi OS by default sets up a user named pi that can use sudo to gain root without a password. I think this is an insecure practice, but assuming you haven t changed it, you will need to ensure it still works once you move to Debian. Raspberry Pi OS had a patch in their sudo package to enable it, and that will be removed when Debian s sudo package is installed. So, put this in /etc/sudoers.d/010_picompat:

pi ALL=(ALL) NOPASSWD: ALL

Also, there may be no password set for the root account. It would be a good idea to set one; it makes it easier to log in at the console. Use the passwd command as root to do so.

Preparation: bluetooth Debian doesn t correctly identify the Bluetooth hardware address. You can save it off to a file by running hcitool dev > /root/bluetooth-from-raspbian.txt. I don t use Bluetooth, but this should let you develop a script to bring it up properly.

Preparation: Debian archive keyring You will next need to install Debian s archive keyring so that apt can authenticate packages from Debian. Go to the bookworm download page for debian-archive-keyring and copy the URL for one of the files, then download it on the pi. For instance:

wget http://http.us.debian.org/debian/pool/main/d/debian-archive-keyring/debian-archive-keyring_2023.3+deb12u1_all.deb

Use sha256sum to verify the checksum of the downloaded file, comparing it to the package page on the Debian site. Now, you ll install it with:

dpkg -i debian-archive-keyring_2023.3+deb12u1_all.deb

Package first steps From here on, we are making modifications to the system that can leave it in a non-bootable state. Examine /etc/apt/sources.list and all the files in /etc/apt/sources.list.d. Most likely you will want to delete or comment out all lines in all files there. Replace them with something like:

deb http://deb.debian.org/debian/ bookworm main non-free-firmware contrib non-free
deb http://security.debian.org/debian-security bookworm-security main non-free-firmware contrib non-free
deb https://deb.debian.org/debian bookworm-backports main non-free-firmware contrib non-free

(you might leave off contrib and non-free depending on your needs) Now, we re going to tell it that we ll support arm64 packages:

dpkg --add-architecture arm64

And finally, download the bookworm package lists:

apt-get update

If there are any errors from that command, fix them and don t proceed until you have a clean run of apt-get update.

Moving /boot to /boot/firmware The boot FAT partition I mentioned above is mounted at /boot by Raspberry Pi OS, but Debian s scripts assume it will be at /boot/firmware. We need to fix this. First:

umount /boot
mkdir /boot/firmware

Now, edit fstab and change the reference to /boot to be to /boot/firmware. Now:

mount -v /boot/firmware
cd /boot/firmware
mv -vi * ..

This mounts the filesystem at the new location, and moves all its contents back to where apt believes it should be. Debian s packages will populate /boot/firmware later.

Installing the first packages Now we start by installing the first of the needed packages. Eventually we will wind up with roughly the same set Debian uses.

apt-get install linux-image-arm64
apt-get install firmware-brcm80211=20230210-5
apt-get install raspi-firmware

If you get errors relating to firmware-brcm80211 from any commands, run that install firmware-brcm80211 command and then proceed. There are a few packages that Raspbian marked as newer than the version in bookworm (whether or not they really are), and that s one of them.

Configuring the bootloader We need to configure a few things in /etc/default/raspi-firmware before proceeding. Edit that file. First, uncomment (or add) a line like this:

KERNEL_ARCH="arm64"

Next, in /boot/cmdline.txt you can find your old Raspbian boot command line. It will say something like:

root=PARTUUID=...

Save off the bit starting with PARTUUID. Back in /etc/default/raspi-firmware, set a line like this:

ROOTPART=PARTUUID=abcdef00

(substituting your real value for abcdef00). This is necessary because the microSD card device name often changes from /dev/mmcblk0 to /dev/mmcblk1 when switching to Debian s kernel. raspi-firmware will encode the current device name in /boot/firmware/cmdline.txt by default, which will be wrong once you boot into Debian s kernel. The PARTUUID approach lets it work regardless of the device name.

Purging the Raspbian kernel Run:

dpkg --purge raspberrypi-kernel

Upgrading the system At this point, we are going to run the procedure beginning at section 4.4.3 of the Debian release notes. Generally, you will do:

apt-get -u upgrade
apt full-upgrade

Fix any errors at each step before proceeding to the next. Now, to remove some cruft, run:

apt-get --purge autoremove

Inspect the list to make sure nothing important isn t going to be removed.

Removing Raspbian cruft You can list some of the cruft with:

apt list '~o'

And remove it with:

apt purge '~o'

I also don t run Bluetooth, and it seemed to sometimes hang on boot becuase I didn t bother to fix it, so I did:

apt-get --purge remove bluez

Installing some packages This makes sure some basic Debian infrastructure is available:

apt-get install wpasupplicant parted dosfstools wireless-tools iw alsa-tools
apt-get --purge autoremove

Installing firmware Now run:

apt-get install firmware-linux

Resolving firmware package version issues If it gives an error about the installed version of a package, you may need to force it to the bookworm version. For me, this often happened with firmware-atheros, firmware-libertas, and firmware-realtek. Here s how to resolve it, with firmware-realtek as an example:

1. Go to https://packages.debian.org/PACKAGENAME for instance, https://packages.debian.org/firmware-realtek. Note the version number in bookworm in this case, 20230210-5.
2. Now, you will force the installation of that package at that version:

   apt-get install firmware-realtek=20230210-5
   

3. Repeat with every conflicting package until done.
4. Rerun apt-get install firmware-linux and make sure it runs cleanly.

Also, in the end you should be able to:

apt-get install firmware-atheros firmware-libertas firmware-realtek firmware-linux

Dealing with other Raspbian packages The Debian release notes discuss removing non-Debian packages. There will still be a few of those. Run:

apt list '?narrow(?installed, ?not(?origin(Debian)))'

Deal with them; mostly you will need to force the installation of a bookworm version using the procedure in the section Resolving firmware package version issues above (even if it s not for a firmware package). For non-firmware packages, you might possibly want to add --mark-auto to your apt-get install command line to allow the package to be autoremoved later if the things depending on it go away. If you aren t going to use Bluetooth, I recommend apt-get --purge remove bluez as well. Sometimes it can hang at boot if you don t fix it up as described above.

Set up networking We ll be switching to the Debian method of networking, so we ll create some files in /etc/network/interfaces.d. First, eth0 should look like this:

allow-hotplug eth0
iface eth0 inet dhcp
iface eth0 inet6 auto

And wlan0 should look like this:

allow-hotplug wlan0
iface wlan0 inet dhcp
    wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf

Raspbian is inconsistent about using eth0/wlan0 or renamed interface. Run ifconfig or ip addr. If you see a long-named interface such as enx<something> or wlp<something>, copy the eth0 file to the one named after the enx interface, or the wlan0 file to the one named after the wlp interface, and edit the internal references to eth0/wlan0 in this new file to name the long interface name. If using wifi, verify that your SSIDs and passwords are in /etc/wpa_supplicant/wpa_supplicant.conf. It should have lines like:

network= 
   ssid="NetworkName"
   psk="passwordHere"
 

(This is where Raspberry Pi OS put them).

Deal with DHCP Raspberry Pi OS used dhcpcd, whereas bookworm normally uses isc-dhcp-client. Verify the system is in the correct state:

apt-get install isc-dhcp-client
apt-get --purge remove dhcpcd dhcpcd-base dhcpcd5 dhcpcd-dbus

Set up LEDs To set up the LEDs to trigger on MicroSD activity as they did with Raspbian, follow the Debian instructions. Run apt-get install sysfsutils. Then put this in a file at /etc/sysfs.d/local-raspi-leds.conf:

class/leds/ACT/brightness = 1
class/leds/ACT/trigger = mmc1

Prepare for boot To make sure all the /boot/firmware files are updated, run update-initramfs -u. Verify that root in /boot/firmware/cmdline.txt references the PARTUUID as appropriate. Verify that /boot/firmware/config.txt contains the lines arm_64bit=1 and upstream_kernel=1. If not, go back to the section on modifying /etc/default/raspi-firmware and fix it up.

The moment arrives Cross your fingers and try rebooting into your Debian system:

reboot

For some reason, I found that the first boot into Debian seems to hang for 30-60 seconds during bootstrap. I m not sure why; don t panic if that happens. It may be necessary to power cycle the Pi for this boot.

Troubleshooting If things don t work out, hook up the Pi to a HDMI display and see what s up. If I anticipated a particular problem, I would have documented it here (a lot of the things I documented here are because I ran into them!) So I can t give specific advice other than to watch boot messages on the console. If you don t even get kernel messages going, then there is some problem with your partition table or /boot/firmware FAT partition. Otherwise, you ve at least got the kernel going and can troubleshoot like usual from there.

I write this in the context of my decision to ditch Raspberry Pi OS and move everything I possibly can, including my Raspberry Pi devices, to Debian. I will write about that later. But for now, I wanted to comment on something I think is often overlooked and misunderstood by people considering distributions or operating systems: the huge importance of getting security updates in an automated and easy way.

Background Let s assume that these statements are true, which I think are well-supported by available evidence:

1. Every computer system (OS plus applications) that can do useful modern work has security vulnerabilities, some of which are unknown at any given point in time;
2. During the lifetime of that computer system, some of these vulnerabilities will be discovered. For a (hopefully large) subset of those vulnerabilities, timely patches will become available.

Now then, it follows that applying those timely patches is a critical part of having a system that it as secure as possible. Of course, you have to do other things as well good passwords, secure practices, etc but, fundamentally, if your system lacks patches for known vulnerabilities, you ve already lost at the security ballgame.

How to stay patched There is something of a continuum of how you might patch your system. It runs roughly like this, from best to worst:

1. All components are kept up-to-date automatically, with no intervention from the user/operator
2. The operator is automatically alerted to necessary patches, and they can be easily installed with minimal intervention
3. The operator is automatically alerted to necessary patches, but they require significant effort to apply
4. The operator has no way to detect vulnerabilities or necessary patches

It should be obvious that the first situation is ideal. Every other situation relies on the timeliness of human action to keep up-to-date with security patches. This is a fallible situation; humans are busy, take trips, dismiss alerts, miss alerts, etc. That said, it is rare to find any system living truly all the way in that scenario, as you ll see.

What is your system ? A critical point here is: what is your system ? It includes:

• Your kernel
• Your base operating system
• Your applications
• All the libraries needed to run all of the above

Some OSs, such as Debian, make little or no distinction between the base OS and the applications. Others, such as many BSDs, have a distinction there. And in some cases, people will compile or install applications outside of any OS mechanism. (It must be stressed that by doing so, you are taking the responsibility of patching them on your own shoulders.)

How do common systems stack up?

• Debian, with its support for unattended-upgrades, needrestart, debian-security-support, and such, is largely category 1. It can automatically apply security patches, in most cases can restart the necessary services for the patch to take effect, and will alert you when some processes or the system must be manually restarted for a patch to take effect (for instance, a kernel update). Those cases requiring manual intervention are category 2. The debian-security-support package will even warn you of gaps in the system. You can also use debsecan to scan for known vulnerabilities on a given installation.
• FreeBSD has no way to automatically install security patches for things in the packages collection. As with many rolling-release systems, you can t automate the installation of these security patches with FreeBSD because it is not safe to blindly update packages. It s not safe to blindly update packages because they may bring along more than just security patches: they may represent major upgrades that introduce incompatibilities, etc. Unlike Debian s practice of backporting fixes and thus producing narrowly-tailored patches, forcing upgrades to newer versions precludes a minimal intervention install. Therefore, rolling release systems are category 3.
• Things such as Snap, Flatpak, AppImage, Docker containers, Electron apps, and third-party binaries often contain embedded libraries and such for which you have no easy visibility into their status. For instance, if there was a bug in libpng, would you know how many of your containers had a vulnerability? These systems are category 4 you don t even know if you re vulnerable. It s for this reason that my Debian-based Docker containers apply security patches before starting processes, and also run unattended-upgrades and friends.

The pernicious library problem As mentioned in my last category above, hidden vulnerabilities can be a big problem. I ve been writing about this for years. Back in 2017, I wrote an article focused on Docker containers, but which applies to the other systems like Snap and so forth. I cited a study back then that Over 80% of the :latest versions of official images contained at least one high severity vulnerability. The situation is no better now. In December 2023, it was reported that, two years after the critical Log4Shell vulnerability, 25% of apps were still vulnerable to it. Also, only 21% of developers ever update third-party libraries after introducing them into their projects. Clearly, you can t rely on these images with embedded libraries to be secure. And since they are black box, they are difficult to audit. Debian s policy of always splitting libraries out from packages is hugely beneficial; it allows finegrained analysis of not just vulnerabilities, but also the dependency graph. If there s a vulnerability in libpng, you have one place to patch it and you also know exactly what components of your system use it. If you use snaps, or AppImages, you can t know if they contain a deeply embedded vulnerability, nor could you patch it yourself if you even knew. You are at the mercy of upstream detecting and remedying the problem a dicey situation at best.

Who makes the patches? Fundamentally, humans produce security patches. Often, but not always, patches originate with the authors of a program and then are integrated into distribution packages. It should be noted that every security team has finite resources; there will always be some CVEs that aren t patched in a given system for various reasons; perhaps they are not exploitable, or are too low-impact, or have better mitigations than patches. Debian has an excellent security team; they manage the process of integrating patches into Debian, produce Debian Security Advisories, maintain the Debian Security Tracker (which maintains cross-references with the CVE database), etc. Some distributions don t have this infrastructure. For instance, I was unable to find this kind of tracker for Devuan or Raspberry Pi OS. In contrast, Ubuntu and Arch Linux both seem to have active security teams with trackers and advisories.

Implications for Raspberry Pi OS and others As I mentioned above, I m transitioning my Pi devices off Raspberry Pi OS (Raspbian). Security is one reason. Although Raspbian is a fork of Debian, and you can install packages like unattended-upgrades on it, they don t work right because they use the Debian infrastructure, and Raspbian hasn t modified them to use their own infrastructure. I don t see any Raspberry Pi OS security advisories, trackers, etc. In short, they lack the infrastructure to support those Debian tools anyhow. Not only that, but Raspbian lags behind Debian in both new releases and new security patches, sometimes by days or weeks. Live Migrating from Raspberry Pi OS bullseye to Debian bookworm contains instructions for migrating Raspberry Pis to Debian.

Review: The Afterward, by E.K. Johnston

Publisher:	Dutton Books
Copyright:	February 2019
Printing:	2020
ISBN:	0-7352-3190-7
Format:	Kindle
Pages:	339

The Afterward is a standalone young adult high fantasy with a substantial romance component. The title is not misspelled. Sir Erris and her six companions, matching the number of the new gods, were successful in their quest for the godsgem. They defeated the Old God and destroyed Him forever, freeing King Dorrenta from his ensorcellment, and returned in triumph to Cadrium to live happily ever after. Or so the story goes. Sir Erris and three of the companions are knights. Another companion is the best mage in the kingdom. Kalanthe Ironheart, who distracted the Old God at a critical moment and allowed Sir Erris to strike, is only an apprentice due to her age, but surely will become a great knight. And then there is Olsa Rhetsdaughter, the lowborn thief, now somewhat mockingly called Thief of the Realm for all the good that does her. The reward was enough for her to buy her freedom from the Thief's Court. It was not enough to pay for food after that, or enough for her to change her profession, and the Thief's Court no longer has any incentive to give her easy (or survivable) assignments. Kalanthe is in a considerably better position, but she still needs a good marriage. Her reward paid off half of her debt, which broadens her options, but she's still a debt-knight, liable for the full cost of her training once she reaches the age of nineteen. She's mostly made her peace with the decisions she made given her family's modest means, but marriages of that type are usually for heirs, and Kalanthe is not looking forward to bearing a child. Or, for that matter, sleeping with a man. Olsa and Kalanthe fell in love during the Quest. Given Kalanthe's debt and the way it must be paid, and her iron-willed determination to keep vows, neither of them expected their relationship to survive the end of the Quest. Both of them wish that it had. The hook is that this novel picks up after the epic fantasy quest is over and everyone went home. This is not an entirely correct synopsis; chapters of The Afterward alternate between "After" and "Before" (and one chapter delightfully titled "More or less the exact moment of"), and by the end of the book we get much of the story of the Quest. It's not told from the perspective of the lead heroes, though; it's told by following Kalanthe and Olsa, who would be firmly relegated to supporting characters in a typical high fantasy. And it's largely told through the lens of their romance. This is not the best fantasy novel I've read, but I had a fun time with it. I am now curious about the intended audience and marketing, though. It was published by a YA imprint, and both the ages of the main characters and the general theme of late teenagers trying to chart a course in an adult world match that niche. But it's also clearly intended for readers who have read enough epic fantasy quests that they will both be amused by the homage and not care that the story elides a lot of the typical details. Anyone who read David Eddings at an impressionable age will enjoy the way Johnston pokes gentle fun at The Belgariad (this book is dedicated to David and Leigh Eddings), but surely the typical reader of YA fantasy these days isn't also reading Eddings. I'm therefore not quite sure who this book was for, but apparently that group included me. Johnston thankfully is not on board with the less savory parts of Eddings's writing, as you might have guessed from the sapphic romance. There is no obnoxious gender essentialism here, although there do appear to be gender roles that I never quite figured out. Knights are referred to as sir, but all of the knights in this story are women. Men still seem to run a lot of things (kingdoms, estates, mage colleges), but apart from the mage, everyone on the Quest was female, and there seems to be an expectation that women go out into the world and have adventures while men stay home. I'm not sure if there was an underlying system that escaped me, or if Johnston just mixed things up for the hell of it. (If the latter, I approve.) This book does suffer a bit from addressing some current-day representation issues without managing to fold them naturally into the story or setting. One of the Quest knights is transgender, something that's revealed in a awkward couple of paragraphs and then never mentioned again. Two of the characters have a painfully earnest conversation about the word "bisexual," complete with a strained attempt at in-universe etymology. Racial diversity (Olsa is black, and Kalanthe is also not white) seemed to be handled a bit better, although I am not the reader to notice if the discussions of hair maintenance were similarly awkward. This is way better than no representation and default-white characters, to be clear, but it felt a bit shoehorned in at times and could have used some more polish. These are quibbles, though. Olsa was the heart of the book for me, and is exactly the sort of character I like to read about. Kalanthe is pure stubborn paladin, but I liked her more and more as the story continued. She provides a good counterbalance to Olsa's natural chaos. I do wish Olsa had more opportunities to show her own competence (she's not a very good thief, she's just the thief that Sir Erris happened to know), but the climax of the story was satisfying. My main grumble is that I badly wanted to dwell on the happily-ever-after for at least another chapter, ideally two. Johnston was done with the story before I was. The writing was serviceable but not great and there are some bits that I don't think would stand up to a strong poke, but the characters carried the story for me. Recommended if you'd like some sapphic romance and lightweight class analysis complicating your Eddings-style quest fantasy. Rating: 7 out of 10

This Christmas, one of my gifts to my kids was a text adventure (interactive fiction) game for them. Now that they ve enjoyed it, I m releasing it under the GPL v3. As interactive fiction, it s like an e-book, but the reader is also the player, guiding the exploration of the world. The Grumpy Cricket is designed to be friendly for a first-time player of interactive fiction. There is no way to lose the game or to die. There is an in-game hint system providing context-sensitive hints anytime the reader types HINT. There are splashes of humor throughout that got all three of my kids laughing. I wrote it in 2023 for my kids, which range in age from 6 to 17. That s quite a wide range, but they all were enjoying it. You can download it, get the source, or play it online in a web browser at https://www.complete.org/the-grumpy-cricket/

Over roughly the last year and a half I have been participating as a reviewer in ACM s Computing Reviews, and have even been honored as a Featured Reviewer. Given I have long enjoyed reading friends reviews of their reading material (particularly, hats off to the very active Russ Allbery, who both beats all of my frequency expectations (I could never sustain the rythm he reads to!) and holds documented records for his >20 years as a book reader, with far more clarity and readability than I can aim for!), I decided to explicitly share my reviews via this blog, as the audience is somewhat congruent; I will also link here some reviews that were not approved for publication, clearly marking them so. I will probably work on wrangling my Jekyll site to display an (auto-)updated page and RSS feed for the reviews. In the meantime, the reviews I have published are:

• 2022.06.15 A world without E-mail (Cal Newport)
• 2022.08.08 Can AI learn to forget? (Samuel Greentard)
• 2023.01.10 Learn enough developer tools to be dangerous: Command line, text editor and Git version control essentials (Michael Hartl)
• 2023.01.12 Phishing and communication channels: A guide to identifying and mitigating phishing attacks (Gunikhan Sonowal)
• 2023.03.14 Jerusalem Online: Critical cartography for the digital age (Valentina Carraro)
• 2023.04.25 Language, gender and videogames: Using corpora to analyse the representation of gender in fantasy videogames (Frazer Heritage)
• 2023.06.23 Democratizing domain-specific computing (Chi Y., Qiao W., Sohrabizadeh A., Wang J., Cong J.)
• 2023.09.03 A free press, if you can keep it: What natural language processing reveals about freedom of the press in Hong Kong (Giovanna Maria Dora Dore, Arya D. McCarthy, James A. Scharf)
• 2023.11.08 Humble AI (Brian Knowles, Jason D Cruz, John T. Richards, Kush R. Varshney)
• 2023.11.21 The stuff games are made of (Pippin Barr)

It was pointed out to me that I have not blogged about this, so better now than never: Since 2021 I am together with four other hosts producing a regular podcast about Haskell, the Haskell Interlude. Roughly every two weeks two of us interview someone from the Haskell Community, and we chat for approximately an hour about how they came to Haskell, what they are doing with it, why they are doing it and what else is on their mind. Sometimes we talk to very famous people, like Simon Peyton Jones, and sometimes to people who maybe should be famous, but aren t quite yet. For most episodes we also have a transcript, so you can read the interviews instead, if you prefer, and you should find the podcast on most podcast apps as well. I do not know how reliable these statistics are, but supposedly we regularly have around 1300 listeners. We don t get much feedback, however, so if you like the show, or dislike it, or have feedback, let us know (for example on the Haskell Disourse, which has a thread for each episode). At the time of writing, we released 40 episodes. For the benefit of my (likely hypothetical) fans, or those who want to train an AI voice model for nefarious purposes, here is the list of episodes co-hosted by me:

• Gabriella Gonzales
• Jasper Van der Jeugt
• Chris Smith
• Sebastian Graf
• Simon Peyton Jones
• Ryan Trinkle
• Facundo Dominguez
• Marc Scholten
• Ben Gamari
• Andrew Lelechenko (Bodigrim)
• ZuriHac 2023 special
• Arnaud Spiwack
• John MacFarlane

Can t decide where to start? The one with Ryan Trinkle might be my favorite. Thanks to the Haskell Foundation and its sponsors for supporting this podcast (hosting, editing, transscription).

I haven't done one of these in quite a while, long enough that I've already read and reviewed many of these books. John Joseph Adams (ed.) The Far Reaches (sff anthology)
Poul Anderson The Shield of Time (sff)
Catherine Asaro The Phoenix Code (sff)
Catherine Asaro The Veiled Web (sff)
Travis Baldree Bookshops & Bonedust (sff)
Sue Burke Semiosis (sff)
Jacqueline Carey Cassiel's Servant (sff)
Rob Copeland The Fund (nonfiction)
Mar Delaney Wolf Country (sff)
J.S. Dewes The Last Watch (sff)
J.S. Dewes The Exiled Fleet (sff)
Mike Duncan Hero of Two Worlds (nonfiction)
Mike Duncan The Storm Before the Storm (nonfiction)
Kate Elliott King's Dragon (sff)
Zeke Faux Number Go Up (nonfiction)
Nicola Griffith Menewood (sff)
S.L. Huang The Water Outlaws (sff)
Alaya Dawn Johnson The Library of Broken Worlds (sff)
T. Kingfisher Thornhedge (sff)
Naomi Kritzer Liberty's Daughter (sff)
Ann Leckie Translation State (sff)
Michael Lewis Going Infinite (nonfiction)
Jenna Moran Magical Bears in the Context of Contemporary Political Theory (sff collection)
Ari North Love and Gravity (graphic novel)
Ciel Pierlot Bluebird (sff)
Terry Pratchett A Hat Full of Sky (sff)
Terry Pratchett Going Postal (sff)
Terry Pratchett Thud! (sff)
Terry Pratchett Wintersmith (sff)
Terry Pratchett Making Money (sff)
Terry Pratchett Unseen Academicals (sff)
Terry Pratchett I Shall Wear Midnight (sff)
Terry Pratchett Snuff (sff)
Terry Pratchett Raising Steam (sff)
Terry Pratchett The Shepherd's Crown (sff)
Aaron A. Reed 50 Years of Text Games (nonfiction)
Dashka Slater Accountable (nonfiction)
Rory Stewart The Marches (nonfiction)
Emily Tesh Silver in the Wood (sff)
Emily Tesh Drowned Country (sff)
Valerie Vales Chilling Effect (sff)
Martha Wells System Collapse (sff)
Martha Wells Witch King (sff)

The Long Now has an insightful article about air quality [1]. Every country needs food labelling laws like Mexico has [2]. Also we need to abolish the investor state tribunals, companies should just accept local laws and obey them or be treated in the same way as pirates on the high seas. Ian Jackson wrote a good post about conference policies regarding Covid19 [3]. We really need to do more about this, conservatives like to imagine that it s gone away but people are still getting sick and dying of it. John Goerzen wrote an informative article about air gaps and ways they can be part of a useful and usable security system [4]. This YouTube video has a good introduction to LLMs (Large Languge Models) for machine learning [5]. This eye tracker is interesting technology [6]. The video shows it being used for MS Flight Simulator but it can be used for other things. Unfortunately the price of about $550 Australian puts it out of range of a lot of free software work. I think this would be good for tracking the user FOR THEIR BENEFIT so that notifications won t be delivered when the user is concentrating. This ABC article about the risk of a past Covid19 infection exacerbating or accelerating Parkinson s or Alzheimer s is a worry [7]. Sam Hartman wrote an insightful blog post about AI safety, consent, and discussions of sex [8].

• [1] https://longnow.org/ideas/commodification-of-air/
• [2] https://tinyurl.com/yl3wcfzs
• [3] https://diziet.dreamwidth.org/16518.html
• [4] https://www.complete.org/how-gapped-is-your-air/
• [5] https://www.youtube.com/watch?v=zjkBMFhNj_g
• [6] https://www.youtube.com/watch?v=0dmXyM7Q3nc
• [7] https://tinyurl.com/ykvor9sm
• [8] https://hartmans.dreamwidth.org/101223.html

Photo by Pixabay

Ubuntu systems typically have up to 3 kernels installed, before they are auto-removed by apt on classic installs. Historically the installation was optimized for metered download size only. However, kernel size growth and usage no longer warrant such optimizations. During the 23.10 Mantic Minatour cycle, I led a coordinated effort across multiple teams to implement lots of optimizations that together achieved unprecedented install footprint improvements.

Given a typical install of 3 generic kernel ABIs in the default configuration on a regular-sized VM (2 CPU cores 8GB of RAM) the following metrics are achieved in Ubuntu 23.10 versus Ubuntu 22.04 LTS:

• 2x less disk space used (1,417MB vs 2,940MB, including initrd)

• 3x less peak RAM usage for the initrd boot (68MB vs 204MB)

• 0.5x increase in download size (949MB vs 600MB)

• 2.5x faster initrd generation (4.5s vs 11.3s)

• approximately the same total time (103s vs 98s, hardware dependent)

For minimal cloud images that do not install either linux-firmware or modules extra the numbers are:

• 1.3x less disk space used (548MB vs 742MB)

• 2.2x less peak RAM usage for initrd boot (27MB vs 62MB)

• 0.4x increase in download size (207MB vs 146MB)

Hopefully, the compromise of download size, relative to the disk space & initrd savings is a win for the majority of platforms and use cases. For users on extremely expensive and metered connections, the likely best saving is to receive air-gapped updates or skip updates.

This was achieved by precompressing kernel modules & firmware files with the maximum level of Zstd compression at package build time; making actual .deb files uncompressed; assembling the initrd using split cpio archives - uncompressed for the pre-compressed files, whilst compressing only the userspace portions of the initrd; enabling in-kernel module decompression support with matching kmod; fixing bugs in all of the above, and landing all of these things in time for the feature freeze. Whilst leveraging the experience and some of the design choices implementations we have already been shipping on Ubuntu Core. Some of these changes are backported to Jammy, but only enough to support smooth upgrades to Mantic and later. Complete gains are only possible to experience on Mantic and later.

The discovered bugs in kernel module loading code likely affect systems that use LoadPin LSM with kernel space module uncompression as used on ChromeOS systems. Hopefully, Kees Cook or other ChromeOS developers pick up the kernel fixes from the stable trees. Or you know, just use Ubuntu kernels as they do get fixes and features like these first.

The team that designed and delivered these changes is large: Benjamin Drung, Andrea Righi, Juerg Haefliger, Julian Andres Klode, Steve Langasek, Michael Hudson-Doyle, Robert Kratky, Adrien Nader, Tim Gardner, Roxana Nicolescu - and myself Dimitri John Ledkov ensuring the most optimal solution is implemented, everything lands on time, and even implementing portions of the final solution.

Hi, It's me, I am a Staff Engineer at Canonical and we are hiring https://canonical.com/careers.

Lots of additional technical details and benchmarks on a huge range of diverse hardware and architectures, and bikeshedding all the things below:

• https://lists.ubuntu.com/archives/ubuntu-devel/2023-July/thread.html#42652
• https://lists.ubuntu.com/archives/kernel-team/2023-July/thread.html#141412
• https://lists.ubuntu.com/archives/ubuntu-devel/2023-July/thread.html#42707
• https://discourse.ubuntu.com/t/reduce-initramfs-size-and-speed-up-the-generation-in-ubuntu-23-10/38972
• https://lore.kernel.org/all/20230830155820.138178-1-andrea.righi@canonical.com/
• https://lore.kernel.org/all/20230829123808.325202-1-andrea.righi@canonical.com/
• https://facebook.github.io/zstd/

For questions and comments please post to Kernel section on Ubuntu Discourse.