all: require Linux kernel version 2.6.32

[OneOfOne]

The last version of 2.6.23(.17) was released on February 2008 src.
The current CentOS LTS (v7) uses kernel 3.10 src.
Debian's minimum is 3.16 src.

A quick search shows lot of random issues that could have been avoided by supported a slightly newer kernel.

This is a request to bump the minimum required kernel version to at least 3.10.

[mvdan]

I support this change. Other GOOS variants fairly regularly drop support for older versions, and Linux 2.x hasn't had any upstream support at all since 2016 (2.6.32 got extended by Ubuntu/RHEL, other 2.x versions went EOL by 2012). Supporting dozens of Linux versions at once adds cost to maintenance and code complexity, makes testing more difficult, etc.

Worth noting that Debian Stretch, now "oldstable", has long-term support until mid-2022, and is on Linux 3.16 like you say. The actual stable release is on Linux 4.19, which is supported by upstream until 2024.

Similarly, CentOS v7 using Linux 3.10 is supported until 2024. So it seems like we could consider another bump sometime after.

[andrius4669]

glibc now also requires at least 3.2 version since 2.27 (announcement) for all architectures, including x86 ones.
The only issue I can imagine at the moment is old kernels used in OpenVZ VPSes, but they're starting becoming a problem for newer debian versions already.
One I have is currently running "2.6.32-042stab134.7" and debian stretch works on it (uses glibc 2.24), however updating to jessie is not possible due to its use of glibc 2.28.
For non-x86 architectures this shouldn't be an issue, which was also possibly the reason (or at least was part of) why glibc delayed their requirement for 3.2 kernel only for x86 architectures (they required 3.2 kernel in 2.25 version on other architectures).

[networkimprov]

@ianlancetaylor perhaps this should be a proposal?

[ianlancetaylor]

Thanks, moved into proposal process.

[rsc]

This proposal has been added to the active column of the proposals project
and will now be reviewed at the weekly proposal review meetings.
— rsc for the proposal review group

[rsc]

glibc requires 3.2. CentOS apparently requires 3.10.
What are we thinking of changing the minimum to?

And what are the benefits of bumping the minimum?
The link in the top comment is a search for [kernel 2.6.23] in the issue tracker.
Not all of them are bugs in 2.6.23 kernels.

Is there code we will be able to delete, like when we dropped XP?
Would we make Go binaries crash at startup if running on an old kernel?

[rsc]

We are still trying to understand this change, specifically
the exact details (which version? do we take the time to check kernel version and crash at startup on old kernels?)
and benefits (which code can be simplified or deleted?).

Any thoughts?