First blog post (after restarting blogging) is out!

In which I explore the use of kprobes in the middle of a function and reveal that I am not, in fact, very good at reading assembly code... 😅

https://blog.tohojo.dk/2023/04/netfilter-packet-drop-attribution-using-bpf.html

@kernellogger
Yeah, nice work, and thanks for the prodding 😊

I'm hereby announcing my intent to take up blogging again! 😀

https://blog.tohojo.dk/2023/04/its-not-dead-its-resting.html

@kernellogger
I know what you mean! Skipping plumbers myself this year for this reason. I think you could probably present remotely? 🤔

Bugbot status update: it's now able to monitor lore lists and start tracking threads as bugs based on an arbitrary query. E.g. you can mention "bugbot engage" in a thread and the entire thread will be converted to a bugzilla bug (if the email of the person issuing this command matches a bugzilla account with "editbugs" group membership). Any subsequent messages in the thread will be automatically added to the bug as new comments. Any comments posted on the bug via bugzilla interface will be sent to original recipients.

Now working on the other direction -- bugs added in bugzilla will be converted to mailing list threads and sent to proper maintainers (based on certain conditions, e.g. a "bugbot" flag needs to be set to "on" and the cf_subsystem custom field needs to match the corresponding MAINTAINERS entry). Should be done tomorrow, at which point I'll be looking for early testers. :)

The recordings from last week's "Understanding latency" webinar are out. Featuring yours truly for a short bit on #BPF on the second day, and lots of great speakers for the rest of the event!

https://www.understandinglatency.com/recordings-2023

@kernellogger
Who ever said cat herding was a waste of time? 😆 how else are we going to get all the proud roaming felines to pay attention to what's important? 😅

I'll be speaking at this webinar on latency on March 6-8:

https://www.understandinglatency.com/

The organisers were even kind enough to make me a fancy graphics to attach to this post! 😃

Released version 1.3.0 of xdp-tools today!

This release includes three new utilities (xdp-bench, xdp-monitor and xdp-trafficgen) as well as frags support for libxdp and refcounting for XSK sockets!

Get it while it's hot off the press! 😃 #linux #XDP #BPF

https://github.com/xdp-project/xdp-tools/releases/tag/v1.3.0

@kernellogger
Nah, but your general point is still valid - test with upstream, folks! 🙂

@kernellogger
In this particular case I think that all Canonical did with their kernel was "have a working build environment", though... :/

(He's talking about the libxdp dispatcher, which works fine on upstream kernels. I know that because I wrote it 😅)

@ljs @LWN Yup, agreed! I read (almost) everything LWN puts out and it's consistently well-written and informative. Really impressive!

Excellent coverage (as always) from @LWN of the discussions around #BPF API stability in the #Linux kernel

https://lwn.net/SubscriberLink/921088/1946095baf6289a7/

Because it has to be repeated again and again: We need to drastically reduce the number of cars to solve our problems.

Flent is featured in LWN! 😲🤩
https://lwn.net/Articles/920121/

I'm gonna keep posting this until one of you fucking boosts it

@ljs @joel_linux RCU is simply broken down into three parts:

• grace periods
• quiescent states
• synchronization

A quiescent state is a time or action that guarantees all grace periods that were running at the time of the synchronization have finished (but you do not care about grace periods that started after synchronization).

If a link list protected by disabling preemption, then the grace period is when preemption is disabled, and the quiescent state is when all CPUs have scheduled. So you can remove an item from the link list (where all readers must have preemption disabled to read it), and then wait for all CPUs to schedule which guarantees nothing has access to the item, where you are now free to delete it without worrying that something is reading it.

That’s the simple case. There’s more complex cases, but it all comes down to the three parts above.

@larsmb
I use my reMarkable tablet for that, which I think is of a similar size (and also e-ink)? Works well enough - the text is a bit smaller than it would be in print, but it's legible enough, for me at least :)

FACTS ABOUT MASTODON

If you are curious about leaving the cooked turkey site and going to the elephant site, here are some important tips:

1. It sucks. But then, so does every site.

2. You can still shitpost. Take great glee.

3. Picking your server instance is super important.

Ideally you should start at a large instance, and leave because it's full of white suburban NIMBY reactionaries who joined in November because they were promised 0 uncomfortable experiences in their lives and lash out whenever this turns out not to be the case.

Then you move to a smaller server where suddenly you can't talk to your friends because the admin of your instance is feuding with the admin of their instance. Then you wait a month before you can move again.

In this regard, the feudal structure of Mastodon instances is very like early 2000s message boards, whenever the admin got drunk and deleted the site.

4. You can work around the feudalism by running Mastodon yourself. It's the size of a mastodon and costs a fortune.

You can run Pleroma, which is smaller, and is also favoured by Nazis by unfortunate historical accident. Pleroma is perfectly good software that fulfils a need for something smaller than Mastodon, but also the devs are definitely not Nazis but are the other ten guys at the table.

There was a hilarious moment where the guy behind Spinster was so obnoxious he got kicked out of Pleroma and started his own fork called Soapbox/Rebased. He is now known as Soapbox Terf.

The nice people went to Pleroma fork Akkoma, which Soapbox Terf calls the "tr***y server", a review I understand they were delighted by. Try that.

There's also Misskey, which is a bit weird and Japanese, and supports cat ears right there in the protocol.

5. Any bozo who complains about your posts with assertions about the Fediverse that assume it all runs on the rules of mastodon.social is one of the suburban NIMBYs and invariably joined in November. Block and don't look back.

6. If anyone annoys you about your posting, you can improve their feed for them by blocking them from ever seeing your posts. The blocking tools are marvellous.

7. There are NO QUOTE TWEETS on Mastodon and anyone who wants QUOTE TWEETS is an invader, pollutant and corrupting influence despoiling the suburban vistas of Mastodon who only wants quote tweets so they can wreak EVIL.

So quote-tweeting is well supported in Akkoma and Misskey (and forks thereof), is in the Treehouse fork of Mastodon, and will be coming to more Fediverse software soon.

8. In Mastodon, Eugen Rochko has achieved the creation of something greater than himself. And he will *never forgive it*.

9. The Fediverse interprets Website Boy as damage and routes around him.

10. Mastodon is yet another demonstration that worse is better. So come onto Mastodon, and *be* that worse.
====
EDIT: this post is attracting some very dumb reply guys. Consider *not* posting debate club fatuity.

Are you someone who has a simple fix for something in the Linux kernel, but haven't bothered submitting a patch because you find the email workflow daunting? Can be a bugfix, spelling correction, anything at all.

If so, I want to talk to you! I have tools that simplify this process quite a bit, but I need more feedback from people who aren't long-term Linux maintainers.

Please reach out, either via here or by emailing mricon@kernel.org.