Notices by Christian Brauner ?? (brauner@mastodon.social)

Replaced sudo with run0 and I'm very happy to have one less setuid binary to worry about.

#systemd #Linux

Picked back up the work for VFS {g,u}id squashing. IOW, mapping all {g,u}ids down to a single {g,u}id. Any process that doesn't have that {g,u}id but is still privileged otherwise will write to disk as the squashed {g,u}id. I just finished a draft and selftests that miraculously work.

https://web.git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git/log/?h=work.idmapped.squash

Probably "bugs galore" at this point. Needs more thinking.

#linux #kernel #vfs #filesystems

I think multi-threaded exec behavior needs to be illegal:
https://web.git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git/commit/?h=vfs-6.15.pidfs&id=3ae8576617e88a2b3cdbad6d8087be3454a4b326

de_thread() is an insult to humanity.

https://lwn.net/Articles/1010667

I want this for struct file allocations.

We've removed #reiserfs and now we're removing #sysv https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git/log/?h=vfs-6.15.sysv

The code removal continues.

#kernel #linux #fs

@osandov 🤡

@axboe @osandov This was actually the first time I ever read Phoronix comments. Immediately regretted it.

@osandov you already made it to Phoronix.
https://www.phoronix.com/news/Linux-6.14-Faster-kcore-Reads

util-linux has merged support for statmount() and listmount() to list mounts:
https://github.com/util-linux/util-linux/pull/3092#event-15865684400

This should be a nice performance improvement.

See https://brauner.io/2024/12/16/list-all-mounts.html for some details on listmount() and statmount().

#linux #kernel

I've written a post that shows how to list all mounts in all mount namespaces (all mounts on the system) using new apis we added to the #vfs this year.

https://brauner.io/2024/12/16/list-all-mounts.html

#kernel #linux #vfs

@corbet fwiw, I tend to not use it unless the message really isn't getting across.

@corbet Any specific example that triggered this?

I can probably mange to free up another 8 bytes in struct file by killing f_version and moving it into the few filesystems that care about it.

That would give us back 8 bytes for future expansions.

It's a rough draft and lacking commit messages but it should work (famous last words)...

https://github.com/brauner/linux/commits/vfs.file.f_version

#linux #kernel

I just added nine new EINVALs to the move_mount() manpage...

That commit message

kernel test robot noticed a 9.1% improvement of stress-ng.sockfd.ops_per_sec on:

commit: d9f21b3613337b55cc9d4a6ead484dca68475143 ("af_unix: Try to run GC async.")
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d9f21b3613337b55cc9d4a6ead484dca68475143

is very scary to people who remember the "pleasantness" we've already gotten out of this codepath.

I'm done writing groff.
https://github.com/brauner/man-pages-md

fyi https://fosdem.org/2024/schedule/track/kernel
happening rn.

I hadn't read that commit message until now. 😅

Hey #Linux #Kernel people. Last year we had the first #Kernel Devroom at #FOSDEM. And we're running the #Kernel Devroom for #FOSDEM in 2024 as well!

#FOSDEM 2024 is taking place over the weekend of the 3 & 4 February in Brussels, Belgium!

It is a wonderful event that's very close to my and a lot of people's hearts!

Join @rppt, Daniel Borkmann, and @stgraber, and myself and make this another great #FOSDEM!

We're very excited for your submissions!

https://lists.fosdem.org/pipermail/fosdem/2023q4/003536.html

It's wild to me that we keep putrified architectures around in #Linux for that long in the first place. And then when we finally remove it people argue for them to be put back in.

I really have a hard time understanding this.

I had one of those ia64 servers at home for about a month which I actually picked up from someone in Berlin just to fscking test copy_thread() changes in 9ba27414f2ec

https://lwn.net/Articles/950466/ #LWN #ia64