#LinuxKernel
#Linux 6.4-rc5 is now available for public testing at https://kernel.org and Linus Torvalds says that there's "nothing particularly strange here." Happy testing!
#Linux #kernel 6.4-rc5 is out: https://lore.kernel.org/all/CAHk-%3DwifuPqAFXQQTTLkp_%2BFMzxGFHpSG-hEtZazG-46s%3DnoAw@mail.gmail.com/
```Nothing particularly strange here […]
[…] I think we're in good shape and nothing makes me think this release wouldn't be one of the nice, boring, regular ones. Yes, there are a couple of regressions being tracked, but hopefully we'll get them all.
Famous last words.
So please do test, and try to prove me wrong,
Linus``` #LinuxKernel
From the tales of "#wikipedia sometimes is a bit off":
```Real-time PREEMPT_RT patches, included into the mainline #Linux [#kernel] since version 2.6 [...]```[1]
Maybe somebody should tell the maintainers of the RT-Tree that their stuff already made it upstream ages ago. 😂
[1] https://en.wikipedia.org/wiki/Linux_kernel#Scheduling_and_preemption #LinuxKernel
New Blog Post: Some links from May 2023
https://pbarker.dev/posts/2023-05-31/some-links-may-2023/
I'm still in the process of trying out different styles of blogging to see what works for me. Today we'll be roleplaying as a link blog, but with one aggregate post covering the month of May instead of one post per link. Let me know what you think!
Topics covered: #C #LinuxKernel #Rust #Python and a grab-bag of others.
#Linux 6.3.5, 6.1.31, 5.15.114, 5.10.181, 5.4.244, 4.19.284, and 4.14.316 kernels are now available for download from https://kernel.org/
#Linux #kernel 6.3.5 is out, which among others fixes[1] the #XFS metadata corruption that can occur with earlier 6.3.y releases. It has been seen in the wild by a number of users and made the news.
[1] see https://lore.kernel.org/all/ZHKB%2FKD1yyx77fop@dread.disaster.area/ and https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-6.3.y&id=74475bc78dd993f17492844f404da41932d8b4eb #LinuxKernel
#Linux 6.4-rc4 is now available for public testing at https://kernel.org and Linus Torvalds says that "things look fairly normal." Happy testing!
#Linux #kernel 6.4-rc4 is out – about half a day earlier than usual:
https://lore.kernel.org/lkml/CAHk-=whwNMtwpMxcsdC4bysY+5E9E_wNeUz=R-iciy3DJwQ+vg@mail.gmail.com/ #LinuxKernel
```I'm traveling most of the day today, so the 6.4-rc4 release is tagged and pushed out a few hours earlier than usual.
[…]
Nothing stands out to me, but the shortlog is appended for people who want to scroll through the details.
Please do continue testing,
Linus```
The fix for the #Linux #kernel #XFS metadata corruption in 6.3.y that made the news has been found and is now queued for #LinuxKernel 6.3.5 [edit: rc is now out, release likely on Tue or Wed]:
https://lore.kernel.org/all/ZHKB%2FKD1yyx77fop@dread.disaster.area/
```A regression in 6.3.0 has been identified in XFS that causes filesystem corruption. It has been seen in the wild by a number of users […]
A reproducer for the corruption was found yesterday and, soon after than, the cause of the corruption reports was identified. […]```
Some updates ...for the curious ... :)
#linux #linuxkernel #kernel #opensource #linuxadmin #sysadmin #operatingsystem #git
"#drgn is a powerful and flexible [#Linux #kernel] debugger. With drgn, one can write scripts in python to analyze either a live system or a vmcore or a program. […] With drgn, the vmcore analysis seems like natural coding. Having the extensive collection of python libraries also helps, as we can use complex algorithms and data structures to aid with system analysis."
https://blogs.oracle.com/linux/post/enter-the-drgn #LinuxKernel
The next Portland Linux kernel meetup will be June 21st
https://www.meetup.com/portland-linux-kernel-meetup/events/293767215/
#portland #pdx #linux #linuxkernel
Interesting, the #Linux #kernel device mapper target "dm-vdo" that allows deduplication and compression is finally submitted upstream:
v1: https://lore.kernel.org/all/20230509010545.72448-1-corwin@redhat.com/
v2: https://lore.kernel.org/all/20230523214539.226387-1-corwin@redhat.com/
122 files changed, 58741 insertions(+) 🥴
```[…] The dm-vdo target provides inline deduplication, compression, zero-block elimination, and thin provisioning. A dm-vdo target can be backed by up to 256TB of storage, and can present a logical size of up to 4PB. […]``` #LinuxKernel #DeviceMapper
...and some peeking ...
#linux #linuxkernel #kernel #opensource #operatingsystemadministration
#Linux 6.3.4, 6.1.30, and 5.15.113 kernels are now available for download at https://kernel.org
```You don't want the #kernel to have a stable [driver] API: it'll kill #Linux.```
@gregkh said that a few days ago here: https://www.youtube.com/watch?v=yilvkzDrRLk&t=2464s
It's good that he's not getting tired of repeating this, as it's a slightly hidden aspect – and thus something many people easily miss. #LinuxKernel
#Linux 6.4-rc3 kernel is now available for public testing and Linus Torvalds says that "nothing really huge stands out there." Happy testing! https://lkml.org/lkml/2023/5/21/226
Fun corner cases:
If you encounter a #LinuxKernel regression when updating from #Linux v6.2.14 to v6.3.2, it's unclear if it's a mainline regression (e.g. v6.2..v6.3) or a stable-specific regression – and thus unclear who has to handle it[1].
That's because the stable team might have caused the issue with a broken backport that went into #kernel v6.3.2 – which might have hit v6.2.15 also, which was released in parallel and has many changes in common with 6.3.2.
[1] see https://docs.google.com/document/d/1Yu1QdK9PicMrkPWTHEMWlJ7AC70gXZPtpTA_oCEbKkE/edit?usp=sharing
This post authored by Paul E. McKenney, a Linux kernel subsystem maintainer, shares insights on how to contribute to the Linux kernel smoothly. The post highlights the importance of first identifying the relevant kernel subsystem and getting familiar with its maintainers. It also recommends testing patches and providing detailed explanations... https://developers.facebook.com/blog/post/2023/04/05/contributing-to-linux-kernel-the-easy-way-part-1/ #LinuxKernel #UpstreamContribution #softcorpremium
```I have two options: to pull or not to pull.```
Linus explains why he sometimes refuses to pull from #Linux #kernel subsystem trees when he is unhappy with their maintenance.
```I think the solution may be for those affected people to help Mauro & co.
Clearly the media maintenance doesn't have enough time. I'm not going to pull from a tree where I know that it then may take six *weeks* and one whole release for simple bugs to be fixed.```
https://lore.kernel.org/lkml/CAHk-%3Dwjypw2PL-w5ZBxY97SgRWd21f2V2Cuyw-ebsiTpSNQjBg@mail.gmail.com/ #LinuxKernel
...and some glean on it .... :)
#linux #research #linuxkernel #kernel #git #opensource #linuxadmin #sysadmin #operatingsystemadministration
QOTD (from LWN):
> The consequences of [...] could be severe and contribute to the ongoing CVE-number shortage [...]
Wanna know what the #Linux #kernel 6.4 brings, which is expected on June 25 or July 2?
Then check out the two @LWN articles about the big changes merged for this version now freely available:
#Linux Kernel 6.2 Reaches End of Life, Users Urged to Upgrade to Linux Kernel 6.3 https://9to5linux.com/linux-kernel-6-2-reaches-end-of-life-users-urged-to-upgrade-to-linux-kernel-6-3
#Linux 6.3.3, 6.2.16, 6.1.29, 5.15.112, 5.10.180, 5.4.243, 4.19.283, and 4.14.315 kernels are now available for download at https://kernel.org
Greg released a bunch of new stable and longterm #kernel today with the usual "must upgrade" notice.
Among them is #Linux 6.2.16, which marks the end of the 6.2.y series; users are advised switching to #LinuxKernel 6.3.y.
"Why your #Linux #kernel bug report might be ignored or is fruitless":
https://docs.google.com/document/d/1Yu1QdK9PicMrkPWTHEMWlJ7AC70gXZPtpTA_oCEbKkE/edit?usp=sharing
Feel free to leave comments.
I wonder what to do with that text[1]. Add it to the #LinuxKernel's documentation? Just publish it somewhere and keep it updated?
[1] I had a few incidents recently that made me think "such a text would be really good to have" -- and then simply started to work on in on two longer train rides.
App Summit 2023: Linux-Desktops gemeinsam auf neuen Wegen
Auf dem Linux App Summit 2023 stellten Entwickler unterschiedlicher Linux-Plattformen ihre Arbeit vor und diskutierten über neue Ansätze.
Posted v1 of a patch reworking the section about "Expectations and best practices for fixing regressions" in the #Linux #kernel's "Handling #regressions" document:
https://lore.kernel.org/linux-doc/6971680941a5b7b9cb0c2839c75b5cc4ddb2d162.1684139586.git.linux@leemhuis.info/ #LinuxKernel
Sadly the section grew somewhat, but it now covers the interaction with stable/longterm kernels better and groups the rules of thumb to make the text easier to read.
#Linux #kernel 6.4-rc2 is out:
```[…] This being rc2, it's been a fairly calm week as people are only starting to find any issues from the merge window, but it all looks fine. […]```
https://lore.kernel.org/lkml/CAHk-=wj3jDtVCi2LqyijGzut2cq=AkPrAMfF0+6gtZ1WB6ruWQ@mail.gmail.com/ #LinuxKernel
#Linux 6.4-rc2 is now available for public testing and Linus Torvalds says that "it's been a fairly calm week as people are only
starting to find any issues from the merge window, but it all looks
fine." https://lkml.org/lkml/2023/5/14/248
A cup of hot coffee ☕ and Eric Clapton's number
🎶 Got To Get Better 🎶
#life #coffee #music #linux #research #linuxadmin #sysadmin #opensource #kernel #linuxkernel
Debian 11 Linux, LMDE5 Kernel Update 5.10.179-1.
The Linux Kernel is responsible for hardware and drivers support. Note that this update will not remove your existing kernel. You will still be able to boot with the current kernel by choosing the advanced options in your boot menu.
#Linux, #LinuxKernel, #Debian, #LMDE5.
Read more here: https://www.linuxexperten.com/news/debian-11-linux-lmde5-kernel-update-510179-1
#Linux 6.3.2, 6.2.15, 6.1.28, and 5.15.111 kernels are now available for download at https://kernel.org #OpenSource #LinuxKernel
#LKML quote of the day from @torvalds on avoiding compiler warnings:
```you can make some compilers happy all of the time, and all compilers happy some of the time, but you can't make all compilers happy all of the time```
https://lore.kernel.org/all/CAHk-=whtWTqXXD29n4z0qni-xM_4OPE-6u3vw_qjkiz05BHVZg@mail.gmail.com/ #LinuxKernel #Linux #kernel
Kent submitted the #bcachefs filesystem ("a new COW fs") for review and #Linux #kernel inclusion: https://lore.kernel.org/all/20230509165657.1735798-1-kent.overstreet@linux.dev/
```Status:
Snapshots have been declared stable; […]
Erasure coding is getting really close; […]
Tons of scalabality work finished over the past year […]
```
Reminder, wenn ihr Meldungen wie "Root-Rechte für lokale Angreifer dank Lücken im #Linux-#Kernel"[1] lest, denkt immer dran:
Das ist nur die Spitze des Eisbergs.
Letztes Jahr etwa gab es über 300 Schwachstellen beim #LinuxKernel, die CVE-IDs bekommen haben[2]; und sicher Dutzende oder vermutlich eher Hunderte, die keinen bekommen haben, weil die Entwickler vieles stillschweigend beseitigen[3].
[1] https://www.heise.de/news/Luecken-im-Linux-Kernel-erlauben-lokale-Rechteausweitung-8992648.html
[2] https://www.cvedetails.com/product/47/Linux-Linux-Kernel.html
[3] https://www.heise.de/select/ct/2021/16/2117313221941668529 #paywall
Lücken im Linux-Kernel erlauben lokale Rechteausweitung | heise online
https://heise.de/-8992648 #Betriebssystem #Linux #LinuxKernel #Sicherheitslücken
Lücken im Linux-Kernel erlauben lokale Rechteausweitung
In zwei Komponenten des Linuxkernels verstecken sich Sicherheitslücken, die lokalen Angreifern eine Rootshell spendieren. Ein erster Exploit ist öffentlich.
Interesting things the #Linux #kernel's #XFS developers are doing:
```Oh, CONFIG_XFS_DEBUG=y, which means: […] We randomly chose a near block allocation strategy to use to improve code coverage, not the optimal one for IO performance. Hence the CPU usage and allocation patterns that impact IO performance are simply not predictable or reproducable from run to run. So, yeah, trying to bisect […] will not be reliable....```
https://lore.kernel.org/all/20230509071053.GE2651828@dread.disaster.area/ #LinuxKernel
Reminder: a #kernel where `uname -r` prints something like "5.15.0-71-generic" is a vendor kernel that is likely quite different from #Linux 5.15.71[1].
In case of problems with such a kernel you thus must report them to your vendor.
That's because almost all upstream #LinuxKernel developers don't care about problems in such kernels, as they might happen due to modifications the vendor applied.
[1] it in fact is likely based on a much later Linux 5.15.y release
Linus Torvalds Announces First #Linux Kernel 6.4 Release Candidate https://9to5linux.com/linus-torvalds-announces-first-linux-kernel-6-4-release-candidate
The tale of -mrtd in GCC and Clang
I'm planning to submit a rewritten section about "expectations and best practices for fixing [#Linux #kernel regressions]" in https://docs.kernel.org/process/handling-regressions.html as RFC early next week.
If you want a early look, follow this link:
https://gitlab.com/knurd42/linux/-/compare/master...docs-handling-regs-procedures-v1?from_project_id=11281838#702893b97b365e04d2e19a5428975ff6a59111c0_201_132 #LinuxKernel
```[…] case of weird hardware utilization. […] insert rows into their QuestDB database, but along with disk writes, they also observed significant disk reads. That's definitely not expected from a write-only workload, so we had to get to the bottom of this problem.[…]
As a result, we found a sub-optimal #kernel readahead behavior. […] The rest was as simple as using #madvise in our code to disable the readahead in table writers. […]```
https://questdb.io/blog/investigating-linux-phantom-disk-reads/ #Linux #LinuxKernel
Hmmm, immutable #Linux distros are currently ignored by the "How to quickly build a trimmed #LinuxKernel" text I recently added to the #kernel's documentation[1].
Is that fine for now? Or should I add a sentence or two about those?
For @fedora #silverblue at al. it seems using "ostree admin unlock --hotfix" might be the best solution when say doing a bisection.
But what's the best way for @opensuse MicroOS?
[1]https://docs.kernel.org/next/admin-guide/quickly-build-trimmed-linux.html
Andrey Konovalov updated his #Linux #kernel exploitation collection.
https://github.com/xairy/linux-kernel-exploitation/commit/5ec0dd2837113e9199b76006391ff8e50c60425c #LinuxKernel
Now freely available: The @LWN article about "The early days of Linux" from Lars Wirzenius (@liw), who "was there when Linux started":
https://lwn.net/Articles/928581/ #Linux #kernel #LinuxKernel
```I started my computer science studies at the University of Helsinki in the fall of 1988, and met Linus Torvalds, who was the other new Swedish speaking student in computer science that year. Toward the end of that first year, we had gotten access to a Unix server, and I accidentally found Usenet, […]```
Now that's a cover letter! 📚
https://lore.kernel.org/lkml/20230414225551.858160935@linutronix.de/
#linux #linuxkernel #lkml
Sadly the dry humour @corbet used at the start of the article didn't fit into above toot, hence find it here for your pleasure:
"While the [#Linux] 6.3 #kernel has gained more support for the #Rust language, it still remains true that there is little that can be done in Rust beyond the creation of a "hello world" module. That functionality was already available in C, of course, with a level of safety similar to what Rust can provide."
Werner Fischer published a new version of his #Linux Storage Stack Diagram which now covers #Kernel 6.2:
https://www.thomas-krenn.com/en/wikiEN/index.php?title=Linux_Storage_Stack_Diagram #LinuxKernel
/me wonders at what point someone will set up a job sending the output of #Linux checkpatch.pl script in reply to every #kernel patch posted to one of its development mailing lists.
https://docs.kernel.org/dev-tools/checkpatch.html #LinuxKernel
Posted v2 of my patch adding a text about "How to quickly build a trimmed #Linux #kernel" to the #LinuxKernel's documentation:
Rendered version:
objtool: Honey, I shrunk the instruction
That's the title peterz used for a patch-set that reduces the memory usage of an #Linux #kernel allyesconfig build by about 6G and also speeds it up by about 55 seconds in his testing.
https://lore.kernel.org/all/20230208171756.898991570@infradead.org/ #LinuxKernel
Trigger was Boris, as he "complained he could no longer build allyesconfig on his 32G desktop machine without having OOM terminate either objtool or chrome." 😂
TIL there's actually two hardening lists, https://lore.kernel.org/linux-hardening/ and https://lore.kernel.org/kernel-hardening/
I wonder what the difference is... looks like linux-hardening is the one listed in MAINTAINERS and used for KSPP?
To everyone :)
010101110110100101110011011010000010000001111001011011110111010100100000011000010010000001110110011001010111001001111001001000000110100001100001011100000111000001111001001000000110111001100101011101110010000001111001011001010110000101110010
#linux #research #linuxadmin #sysadmin #opensource #linuxkernel #kernel
The #LinuxKernel merge window closed, so here is a #thread about what I've been working on for #Linux 6.3 🐧
1/6🧵
Matthew Brost announced "Xe", a new #Linux #kernel #drm driver for #Intel GPUs that supports both integrated and discrete platforms starting with Tiger Lake:
https://lore.kernel.org/dri-devel/20221222222127.34560-1-matthew.brost@intel.com/ #LinuxKernel
"[…] The intention of this new driver is to have a fresh base to work from that is unencumbered by older platforms, whilst also taking the opportunity to rearchitect our driver to increase sharing across the drm subsystem […]"
Some #BPF / #eBPF highlights from the big net merge for #Linux #kernel 6.2 (see https://fosstodon.org/@kernellogger/109510720872601710 #LinuxKernel ):
- Support for user defined BPF objects: the use case is […] for example, linked lists
- bunch of BPF verifier fixes and improvements
- Lots of new BPF docs for various BPF maps
- RCU grace period chaining to BPF to wait for the completion of access from both sleepable and non-sleepable BPF progs
- support storing struct task_struct objects as kptrs in maps
Highlights of the big DRM (Direct Rendering Manager) merge for #Linux #kernel 6.2:
* the addition of the acceleration subsystem framework (merge: https://git.kernel.org/torvalds/c/795bd9bb21c694ebcee38e8026ebeac4a63929bf; docs: https://git.kernel.org/torvalds/c/8c5577a5ccc632685e65168fc6890b72a779f93a)
* support for Intels DG2 by default
* initial Ampere (Nvidia RTX 30) support in Nouveau
* support for new AMD IPs
* PAL-M support in VC4
* support for 'nomodeset' in Fbdev
For more changes see: https://git.kernel.org/torvalds/c/a594533df0f6ca391da003f43d53b336a2d23ffa #LinuxKernel
1498 files changed, 50396 insertions, 29801 deletions
The #Linux #kernel's NFSd maintainers plan to disable support for NFSv2, as can be seen by one of the changes highlighted in the commit with the NFSd updates merged for #LinuxKernel 6.2: https://git.kernel.org/torvalds/c/764822972d64e7f3e6792278ecc7a3b3c81087cd
```In furtherance of removing support for NFSv2 in a subsequent kernel release, a new Kconfig option enables server-side support for NFSv2 to be left out of a kernel build.```
Also new: Support for the ```CB_RECALL_ANY operation […] return any delegations […] low memory scenarios ```
The #Btrfs updates merged for #LinuxKernel 6.2 bring "some nice performance improvements and an update to raid56 reliability": https://git.kernel.org/torvalds/c/149c51f876322d9bfbd5e2d6ffae7aff3d794384 #linux #kernel
"[…] preparation for fscrypt […] discard=async by default for devices that support it […] implement emergency flush reserve to avoid almost all unnecessary transaction aborts due to ENOSPC […]"
Miguel merged v2 of the #rust core additions for the #LinuxKernel (aka "the first batch of changes to upstream the rest of the #Rustang support"(¹)). They showed up in #Linux-next already and it looks like he plans to submit them for inclusion in #kernel 6.2: https://lore.kernel.org/all/20221202161502.385525-1-ojeda@kernel.org/
(¹) reminder, the current Rust support is pretty basic: https://lwn.net/Articles/910762/
I've archived all my old tweets (except RTs) here:
https://vegard.github.io/twitter/
Almost everything has been tagged by subject/topic in case you are only interested in something specific.
Lots of #LinuxKernel, #Programming, #Security, #Fuzzing, #Git, etc. posts.
#introduction time!
I write JavaScript 9 to 5, but I mostly post about my contributions to #linux and #freesoftware projects.
I co-maintain #libinput and I'm a fairly active #linuxkernel hobbyist developer. Mostly adding input features and learning about graphics (DRM/KMS).
I'm also an #elementaryos user and casual contributor and I've contributed to many other projects, specially on the #GNOME and #wayland ecosystems.