Linux kernel 6.1 was released almost in mid-December and it is being adopted by some of the distributions’ newer versions, like Manjaro 22.0 “Sikaris”, the latest Arch Linux ISO, and some others. Now, the Linux kernel team is developing Linux kernel 6.2, which is expected to be released in late February with one week delay since Torvalds expects an 8th release candidate as well; the sixth release candidate is now available for testing.
Linux kernel 6.2 rc6 announcement
Linux kernel 6.2 rc6 arrives with a smaller changelog compared to usual release candidates, bringing mostly bug fixes for the bugs that were still existing in the fifth release candidate. There are many bug fixes related to networking, especially the netfilter and netlink packages, alongside some fixes in the x86 platform. There are a couple of bug fixes for DRM and AMD GPU drivers as well. Linus Torvalds, the developer of the Linux kernel said,
« Here we are, one week later, and rc6 is out.
It’s suspiciously small, but who am I to look a gift horse in the mouth? I’ll take it and hope it’s not an aberration, but instead a sign that 6.2 is shaping up nicely. Call me optimistic, call me naive, but let’s enjoy it and hope the trend continues.
The diffstat looks pretty normal too, with various driver fixes (networking, gpu, i2c and x86 platform drivers stand out) and netfilter fixes leading the pack. But there’s the usual arch updates, random filesystem fixes, and misc other things going on too. The shortlog is appended for people who want to scan through the detailed overview.
I’ve already mentioned this a couple of times earlier: despite rc6 being nice and small, I expect to drag 6.2 out to an rc8 just because of the time lost to the holidays. But I’ll be much happier if we can *keep* the remaining rc’s nice and small. Ok? »
General changes
Linux kernel 6.2 improves the Rust implementation which was introduced in Linux kernel 6.1. The initial support lacked some of the needed features, thus it was not in a really usable shape. With Linux kernel 6.2, Rust will be more practical on Linux.
On the other hand, the split lock detector is receiving a new option to disable the feature. With the release of the Linux kernel, the developers have implemented a feature that slows down badly behaving applications in split locks. However, some of the non-maintained applications and games stuck with this punishment; for example, God of War on Linux became a slideshow because of this punishment system. Now, users can disable this thing by using the split_lock_mitigate option. When it is set to 0, it will no longer punish the bad-behaving application or the user who wants to peacefully play some games.
CPU/memory-related changes
Linux kernel 6.2 brings the Call Depth Tracking mitigation option for Retbleed vulnerability for Intel Skylake CPUs which reduces the performance penalty of the IBRS (Indirect Branch Restricted Speculation) technique but is not as safe as IBRS. On the other hand, Linux kernel 6.2 will enable IBT (Indirect Branch Tracking) by default, which affects Intel’s Tigerlake and newer CPUs. Intel’s SGX Async Exit Notification feature, AEX Notify, and TGS guest support are landing on Linux kernel 6.2 and will be further securing the Intel CPUs as well.
Intel
Intel’s In-Field Scan feature which will help system administrators detect faulty CPU cores was introduced in Linux kernel 5.19. However, it was not working properly. Now, Intel engineers have fixed the issues and it will be available in kernel 6.2. Going on with the news from Intel, the Intel On Demand platform, which is basically a pay-to-unlock and subscription-model hardware is receiving some improvements, including rebranding from Software Defined Silicon and some low-level changes as well.
The Alder Lake and Raptor Lake processors are receiving new updates for HWP (hardware P-states) in order to better calibrate the resulting frequencies on hybrid CPUs.
AMD
Look at the AMD side on changes in Linux kernel 6.2, the company has brought patches for its automatic IBRS feature for Zen 4 CPUs, which we previously mentioned as having a big impact on Intel CPUs for Spectre v2 protection. AMD’s approach is hardware-based; when it is enabled, it resources automatically across privilege-level transitions. Developers can use the spectre_v2=autoibrs option in the kernel to enable it.
AMD has also delivered QoS refinement patches for Slow Memory Bandwidth Allocation (SMBA) with CXL memory and Bandwidth Monitoring Event Configuration (BMEC), which will be available in Genoa processors. Additionally, there are many new metrics in performance monitoring events for new Zen 4-based processors, including L1 and L2 cache activity, branch prediction, and many more for diagnosing performance bottlenecks.
Other
There are some nice improvements for Arm-based systems as well. Linux kernel 6.2 brings support for Arm CoreSight PMU architecture and its Nvidia variation, in addition to the support for dynamic shadow call stacks for switching between the SCS feature and CPU’s pointer authentication function. Additionally, FPDT support lands for boot-time profiling and Arm Scalable Vector Extensions v2.1 instructions are available.
Linux kernel 6.2 brings RISC-V processors to support non-volatile memory devices. It now also supports ftrace in 32-bit RISC-V architecture alongside some other small improvements. Ampere Altra processors, on the other hand, will be able to deliver the sensor data for temperatures, power, and voltages, in addition to boot status and error monitoring information of SMpro co-processors in Linux. AmpareOne core, which is based on Arm, also received a security patch for Spectre-BHB vulnerability.
Apple Silicon is receiving treatment with Linux kernel 6.2 as well. With the new release, Apple Silicon CPU frequency scaling driver will be updated for both M1 and M2 chips. Support M1 series chips are also being mainlined with Linux kernel 6.2, moving away from the downstream Asahi Linux kernel.
GPU-related changes
There are a couple of big changes in Linux kernel Direct Rendering Manager. With Linux kernel 6.2, Intel Arc Graphics will no longer be treated as “experimental”. It also delivers initial accelerated support for Nvidia RTX 3000 series GPUs. AMD on the other hand is enabling new IP blocks and adding DCN2.1 secure display support while fixing problems while building DCN display code on Arm systems. There are some other minor improvements in DRM as well.
Intel
Intel drm-intel-next driver is receiving refactoring in the display code. The drm-intel-gt-next driver has also been updated for memory management improvements and some other small changes. With the treatment change in the Intel i915 driver, Mesa 23.0 for Vulcan can be able able to deliver performance metrics for Intel Arc Graphics. Furthermore, Intel is making its preparations for bringing Meteor Lake integrated graphics support, which will be the series of CPUs that will be introduced in 2023. There are 5 GPU IDs added for Meteor Lake, but they are disabled as expected.
AMD
AMDGPU driver is now enabling the DCN (Display Core Next) support for Arm-based systems on Linux kernel 6.2. There are also many other changes in the driver such as a fix for Vega 10 GPUs’ fans RPMs, Secure Display support for DCN 2.1 driver, and more.
Nvidia
The Nouveau driver for Nvidia graphics cards is receiving many improvements since Nvidia decided to open-source its GPU kernel drivers earlier this year. However, the improvements on kernel 6.2 mostly consist of preparation work for making use of the open-source drivers from Nvidia and some bug fixes. Additionally, it supports OpenGL on the GPUs with Ampere architecture in Mesa 23.0, and it will be possible with Linux kernel 6.2.
File system changes
There are many changes in file system options in Linux kernel 6.2 as well. The RAID5 and RAID6 operations in Btrfs, which were not recommended due to their instability, are currently being repaired. The file system also receives the Reserve Flush Emergency feature, which was understood it was necessary when Facebook’s data centers had problems. Kernel 6.2 will also enable async discard by default.
EXT4 file system also received minor fixes. F2FS, on the other hand, receives atomic replace and per-block age-based extent cache features. exFAT receives some treatments, which improve the performance while creating files and directories, especially on systems with low-performance CPUs. SquashFS now supports IDMAPPED mounts as well.
NTFS3 kernel driver now has the option to hide the files and folders which begin with a dot in addition to a case-insensitive option. One more option in the NTFS3 driver is the windows_names; which makes the folder and file names compatible with Windows operating system by disallowing some special characters and names.
NFSv2, which is a network-optimized file system, now can be removed with the NFSD_V2 option since it was built in the ’80s and was replaced with v3 and v4 already.
Virtualization changes
There are not many changes in the virtualization in Linux kernel 6.2. KVM now has SMM support in x86 and x86_64 systems and has some improvements Hyper-V. The new Intel CPU instructions are also being introduced to guest systems and it receives some fixes and optimizations. Intel TDX KVM, on the other hand, reaches v10 by receiving 108 patches.
Other hardware changes
The networking subsystem is to receive some big improvements like 800 Gbps network support, which is currently in the preparation stage. The TCP kernel code can now handle Proactive Load Balancing across switch links. The subsystem also brings support for several new hardware alongside bridging MAC Authentication Bypass support, improving the TUN network driver’s speed; from 10 Mbps to 10 Gbps.
The sound subsystem receives numerous new hardware support alongside the Intel DSP overhaul and minor improvements in the Intel AVS code.
The Compute Express Link 2.0+ (CXL) subsystem receiving enablement work and CXL 1.x versions are receiving some new functionalities, including Restricted CXL Host topologies, commands for CXL Persistent Memory Security, cache flushing API, and more. A new feature, HID-BPF, that will help with creating workarounds for the devices that do not properly confirm HID specifications will be available in kernel 6.2.
Intel’s Gaudi2 AI accelerators now provide information about faults via a user-space API and allow hard resets on the hardware. Additionally, Linux kernel 6.2 now supports Gaud2 PCU revision 2 as well.
USB and Thunderbolt interfaces are being updated as well, with many small changes. The USB driver drops support for some older hardware in Linux kernel 6.2 and brings wake-on-connect and wake-on-disconnect features for the USB4 interface.
Finally, interestingly enough, the Floppy driver is updated to fix the memory leak issue in the initialization process, which was a problem since the release of Linux kernel 5.11.
Other changes
- Multiple compression stream support for ZRAM on user space
- Support for ChromeOS Human Presence Sensor
- Corsair HX1500i PSU sensor support through USB
- Sensor support for many Asus motherboards
- Support for Sony DualShock 4 controller in the new HID driver
- Depreciation of SLOB allocator
- New dedicated VFS POSIX Active Control Lists API
- Many new device support in HWMON
- New additions to the supported touchscreens
Download Linux kernel 6.2 rc6
You can download and compile the release candidate of Linux kernel 6.2 for testing by following the link below. However, you should avoid installing this release on a mission-critical system since it is not in a stable state yet.
Click here to download the Linux kernel 6.2 rc6
Previous release candidates
Linux kernel 6.2 rc5
Linux kernel 6.2 rc5 announcement is a bit interesting since Linus Torvalds admits his fault of expectation of going back to “normal” after the holidays. However, it seems like it is not the case. Because of this issue, Torvalds expects an 8th release candidate for Linux kernel 6.2, which means the final release will be one week late.
This week’s release candidate includes many fixes as usual, the fixes are a bit focused on btrfs, WiFi, ARM support, a couple of Bluetooth fixes, USB fixes, and more. You can see the full change log in the announcement. Linus Torvalds, the developer of the Linux kernel said,
« Ok, so I thought we were back to normal after the winter holidays at rc4. Now, a week later, I think I was mistaken – we have fairly sizable rc5, so I suspect there was still pent up testing and fixes
from people being off.Anyway, I am expecting to do an rc8 this release regardless, just because we effectively had a lost week or two in the early rc’s, so a sizable rc5 doesn’t really worry me. I do hope we’re done with the release candidates growing, though.
Anyway, there’s a bit of everything in rc5: various driver updates (gpu, rdma, networking, tty, usb..), some architecture updates (mostly loongarch and arm64), some filesystem updates, some core networking, and tooling.
The shortlog is appended as usual. Nothing particularly odd stands out to me. »
Linux kernel 6.2 rc4
Linux kernel 6.2 rc4 is a rather “normal” release since almost everyone returned from the winter holidays, which affected the development. This week’s release candidate has many changes all over the kernel, including perf tool improvements, ASoC driver fixes, AMD GPU DRM driver patches, NVMe improvements, XFS patches, and with slightly more fixes in networking due to a higher number of changes in RxRPC.
Linus Torvalds, the developer of the Linux kernel said,
« It’s Sunday afternoon in some parts of the world, and since I’m going to spend the rest of the day on airports and flights, that’s good enough for me.
So here’s another -rc release, this time with pretty much everybody back from winter holidays, and so things should be back to normal. And you can see that in the size, this is pretty much bang in the middle of a regular rc size for this time in the merge window.
The stats look fairly normal too, perhaps with a slight emphasis on networking that was playing catch-up after the holidays. But there’s various changes all over – scan the appended shortlog for a taste of what has been going on. »
Linux kernel 6.2 rc3
After a dull week of development due to the holidays, Linus Torvalds said that things are starting to look a lot more normal now. The third release candidate brings are a couple of fixes in the DRM drivers of AMD and Intel, the btrfs file system, and the wireless network drivers. You can find the full change log in the Linux kernel 6.2 rc3 announcement. Linus Torvalds, the developer of the Linux kernel said,
« Here we are, another week done, and things are starting to look a lot more normal after that very quiet holiday week that made rc2 so very small.
Nothing in particular here stands out: the bulk of this is driver fixes (networking, gpu, block, virtio – but also usb, fbdev, rdma etc, so a little bit of everything). That is as should be, and just matches where the bulk of the code is.
Outside of the various driver fixes, we’ve got core networking, some filesystem fixes (btrfs, cifs, f2fs and nfs), and some perf tooling work.
With the rest being mostly selftests and documentation.
The shortlog is below, plase do give it a good test, and holler if you find anything. »
Linux kernel 6.2 rc2
The second release candidate for the Linux kernel is a bit dull since that week was covered by the Christmas holiday and New Year’s Eve. Linux kernel 6.2 rc2 fixes some problems in AMD Ryzen 6000 and newer laptops and their S0ix idle behavior with setting Microsoft GUID path being default from now on, instead of AMD GUID. The AMD GUID was causing problems because of the OEM’s incorrect utilization.
Linus Torvalds states that there are some bug fixes in KVM and NVMe, in addition to some work on i915 DRM; those three cover almost all of the changes in Linux kernel 6.2 rc2. Linus Torvalds, developer of the Linux kernel said,
« So the week started so slow due to the holidays that I thought I might not have any reason to do an rc2 at all, but by the end of the week I did end up getting a smattering of pull requests, so here we are. It’s tiny, even smaller than usual for an rc2, and honestly, I’d expect that trend to continue for rc3. A lot of people are still off for another week on a well-deserved winter holiday, and so I suspect things will continue to be fairly quiet.
Anyway, last week saw mainly some nvme fixes, some i915 drm work, and some kvm fixes (and kvm testing fixes). See below for the full shortlog, and if you’re not still in a food coma from the holidays, please do give this all a good testing. »
Linux kernel 6.2 rc1
Linus Torvalds, developer of the Linux kernel said,
« So it’s Christmas Day here, but it’s also Sunday afternoon two weeks after the 6.2 merge window opened. So holidays or not, the kernel development show must go on.
Thanks to a lot of people sending their pull requests early, I got much of the merge window work done before the holidays started in earnest, and mostly before my pre-xmas travel. So despite flight delays, missed connections, and the resulting airport hotel excursions, the merge window mostly went smoothly, and there was no reason to delay rc1.
That said, realistically I expect most people to be on vacation for at least another week, so I wouldn’t be surprised if we end up with a delayed final release due to the season. But it’s too early to worry about that yet, we’ll just have to see how it goes.
Also, 6.2 looks like it’s a bigger release (certainly bigger than 6.1 was). The summary below is, as usual, just my merge log: we’ve got about 13.5k commits from ~1800 people in total in this merge window, which is actually not that far off the total size of the whole 6.1 release. But let’s hope that despite the size, and despite the likely
slow start of the post-merge-window calming down period, we’ll have a smooth release.And in the meantime, Merry Christmas and a Happy New Year to all (replace as appropriate with whatever holiday, if any, you are celebrating). »
Frequently asked questions
What is the most recent Linux kernel?
Currently, the most recent Linux kernel version is 6.1. The 6.2 version is expected to be released in the middle of February 2023.
How do you check the installed Linux kernel version?
You can check the Linux kernel version of your system with three different methods. You can simply use uname -r command to quickly check the Linux kernel version. You can also use cat /proc/version to check the version from a file. Installing the neofetch application is also an option to check the kernel version and it provides additional information about the other packages installed as well.
Can the Linux kernel be customized?
Yes, the Linux kernel can be customized. You can customize the Linux kernel by enabling or disabling specific options, and even adding new functionalities. But it’s a complicated process; you can check online guides about customizing the Linux kernel.
Is it legal to edit the Linux kernel?
Yes, it is legal to edit the Linux kernel since it is under General Public License.
Is the Linux kernel open source?
Yes, the Linux kernel is an open-source project.
Who developed the Linux kernel?
Linus Torvalds has developed and still developing the Linux kernel.
Does Linus Torvalds still work on Linux?
Yes, Linus Torvalds still works on developing the Linux kernel.
What is the Linux kernel written in?
Linux kernel code is written in the standard C programming language.