5.4.2 kernel update feasibility

[deadlysyn]

Distribution (run cat /etc/os-release):

NAME="Pop!_OS"
VERSION="20.04 LTS"
ID=pop
ID_LIKE="ubuntu debian"
PRETTY_NAME="Pop!_OS 20.04 LTS"
VERSION_ID="20.04"
HOME_URL="https://pop.system76.com"
SUPPORT_URL="https://support.system76.com"
BUG_REPORT_URL="https://github.com/pop-os/pop/issues"
PRIVACY_POLICY_URL="https://system76.com/privacy"
VERSION_CODENAME=focal
UBUNTU_CODENAME=focal
LOGO=distributor-logo-pop-os 

Related Application and/or Package Version (run apt policy $PACKAGE NAME):

Linux monolith 5.4.0-7642-generic #46~1598628707~20.04~040157c-Ubuntu SMP Fri Aug 28 18:02:16 UTC  x86_64 x86_64 x86_64 GNU/Linux

Issue/Bug Description:

Noticed local circleci builds were failing. It looks like it's go/kernel compat issue vs circleci. Go runtime errors out suggesting upgrade to 5.4.2+ kernel.

Steps to reproduce (if you know):

In a circleci project I:

circleci config process .circleci/config.yml > .circleci/local-config.yml
circleci local execute -c .circleci/local-config.yml --job build
...
runtime: mlock of signal stack failed: 12
runtime: increase the mlock limit (ulimit -l) or
runtime: update your kernel to 5.3.15+, 5.4.2+, or 5.5+
fatal error: mlock failed

But (rebooted after change, even tried passing --ulimit directly into docker container):

❯ ulimit -l
unlimited

❯ grep memlock /etc/security/limits.conf     
me                soft    memlock         unlimited
me                hard    memlock         unlimited

Expected behavior:

Go 1.14+ runtime calls proceed without ulimt errors.

Other Notes:

I know this is not a "bug" per se, but wondered if 5.4.2+ kernel update was feasible.

TIA.

[deadlysyn]

First thought was "if you want new, just enable proposed updates" but I don't see 5.4.2 there either. Perhaps that means it's a bigger deal than I thought. :-)

[jacobgkau]

Pop!_OS 20.10, which will most likely be released near the end of next month, should include kernel version 5.8.

If you want to try a newer kernel version sooner, you can try following the instructions on the Ubuntu wiki here to install a mainline kernel version: https://wiki.ubuntu.com/Kernel/MainlineBuilds

Please keep in mind that a newer/mainline kernel version is not something we would officially support, since we haven't tested it at all and it does not include our modifications. Looking at your output:

runtime: increase the mlock limit (ulimit -l) or
runtime: update your kernel to 5.3.15+, 5.4.2+, or 5.5+

I would suggest trying to increase the mlock limit instead of changing your kernel version.

This message rang a bell, and I believe it's a workaround for an issue that is already fixed via an Ubuntu patch in the kernel anyway. There is some discussion about that here:

golang/go#37436
golang/go#35777

[deadlysyn]

Thanks for the quick response to an odd question. :-)

I thought I'd raised mlock (ulimit -l) but might have done it wrong. This came even after having:

❯ ulimit -l
unlimited

❯ grep memlock /etc/security/limits.conf     
me                soft    memlock         unlimited
me                hard    memlock         unlimited

Regardless, it sounds like the best option at this point is waiting a month for the official release of 20.10... thanks for the good news and links to reading material!