They say no one is using these older LTS kernels, but I’m running into them all the time on Android devices. I don’t know if the vendors are taking advantage of those updates, but they’re definitely choosing the LTS kernels for their BSPs at release time.
choosing LTS certainly, but backport improvement and delivering updates, most probably never
which is kinda the point of LTS right? or does LTS for kernel mean additional things?
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HWE is just a much newer upstream base. I’ve had issues with their HWE line (6.2 base) but then I’ve had issues with their Generic line (5.15 base) so while newer isn’t always better, older isn’t better either.
Cut from 6(!) years to 2 years. I had no idea the support stretched as far back as 6 years. 2 still seems totally reasonable, especially given all the work put into backwards compatibility in the kernel already.
Sorry for my dumb question but what is the difference between the Linux kernel at kernel.org and say the Linux kernal at Ubuntu.org? It is just different maintainers?
For example I believe the LTS version of Ubuntu runs for 5 years and you can pay for Pro support and get 10 years on their ESM version, if I understand correctly you can keep the same kernel version though the duration.
The Ubuntu kernel is downstream from the actual kernel.org version. Ubuntu just handles support of it for Ubuntu. Kernel.org are the original implementers.
Linus Torvolds and the folks at kernel.org work to continually improve the kernel and ready it for each release cycle.
Ubuntu and other distro maintainers take that work and make sure that they are shipping to you a compiled kernel(s) that dependably works with all other software on their distribution.
The other two answers are correct but missing one maker thing: many major distributions apply patches to the kernel before distributing. So there are very slight modifications.
On your final note, it’s not really the same kernel version throughout, and at times they have bumped up major upstream kernel versions mid-LTS, but even disregarding that, they are constantly applying security patches (think of it as minor version increments with bugfixes from the future).
So sure, you’re running kernel 5.15.0 on Ubuntu LTS 22.04, but maybe you started at 5.15.0-36 and after a few months of incremental upgrades you’ll be running 5.15.0-85.
RIP 22.04 LTS. I have like 20+ servers running this.
Pretty sure Ubuntu LTS is completely unaffected by this.
Correct. They regularly freeze and maintain their own kernel, merging patches in as needed.
5.15.0-83.94-generic
5.15.0 (mainline kennel version at the point it was frozen)
83.94 (Canonical’s version numbering with newer upstream patches merged in over time)
generic (Canonical maintains several specialized flavors of kernel for different needs)They’ve recently put out a “HWE” flavor which just starts at a much newer point in the upstream kernel. I’m not sure what the point is in maintaining the 5.15 and the 6.2 flavors side-by-side.
Sources:
https://ubuntu.com/kernel
https://people.canonical.com/~kernel/info/kernel-version-map.html
