I wrote a longer reply with links, but somehow it didn’t actually post; so this will be shorter and unsourced. Sorry about that.

There already was a discussion, over the course of several years, about whether to add Rust to the kernel. Linus merged rust/kernel into the mainline in 2022, and it was released in Linux 6.1. The patch that Hellwig opposed did not introduce Rust, it just added more Rust.

Hellwig also made it pretty clear that he wasn’t open to discussion. If you read the thread, there were numerous attempts to “talk things over.”

You may be right that Marcan’s posts on Mastodon added nothing productive, though I honestly think there’s some value in sharing behavior like Hellwig’s with the broader programming community. But his posts in the actual mailing list seem pretty sensible, albeit provocatively worded.

Also, in case you didn’t know, similar behavior (to Hellwig’s) led the primary Rust for Linux maintainer, Wedson Almeida Filho, to step down back in August. Marcan is correct that the anti-R4L maintainers are successfully demoralizing the R4L people.

it’s old man screaming at cloud

Not exactly – part of the point of that idiom is that the old man is powerless, and the cloud ignores him. But Hellwig is using his authority as a maintainer to make things more difficult for R4L with his “explicit NACK”.

this drama Martin is doing in social media is pretty much pointless.

Well, maybe, and if you haven’t seen it already, Linus chastised him for that. Several people have spoken up to say that Martin has done this sort of thing before.

But on the other hand, arguably it is important for people who don’t read the Linux kernel mailing list to hear when things like this happen; and if Martin hadn’t posted about it, how would we have known about it? Would The Register have written the summary that they did?

Martin isn’t even relevant! He’s just for the popcorn, like the rest of us! Free kernel development popcorn!

I’m not sure why he phrased things that way, because he was a maintainer of ARM/APPLE, which relies on R4L, until he decided to step down following Linus’s reprimand. So no, he wasn’t just an outside observer.

…do those changes proposed by the project affect the stable branch now?

Not sure which changes you mean, exactly, but the rust/kernel folder in the patch set does indeed already exist in the stable branch.

But…that’s exactly what’s happening. Rust is already in the kernel, with both Linus’s and GKH’s approval. CH is trying to singlehandedly reject any use of Rust in any part of the kernel where he has maintainer status. That’s pretty specific to R4L.

I didn’t use the word “personal”, but it’s inherently somewhat personal in that it’s one person trying to fight back against a decision that Linus and GKH have both endorsed (to put Rust in the kernel). “Crusade” is strong wording, but so is “I will do anything I can to stop this.” That’s far beyond simply “prioritizing [other] things.”

Hector Martin isn’t claiming that Hellwig’s crusade is against Rust, but against R4L. The problem is that the R4L project has always been about Rust in the kernel. “Don’t bring new languages into the kernel” is a crusade against R4L.

Do you take this sentence seriously, or not?

I will do everything I can do to stop this.

As far as I can tell, “this” here refers to literally any Rust code that isn’t constrained within a specific driver. That does indeed seem like a full-on attempt to stop the R4L project entirely.

He does appear to have a real technical concern regarding maintainability.

“Appear” is doing some heavy lifting there. Opponents of the R4L project always couch their objections in technical concerns. For what it’s worth, I can’t actually find any concerns of merit or substance in that particular thread, although navigating mailing list threads is honestly pretty error-prone, so I may have missed it.