syscall: TestAmbientCapsUserns test failing with operation not permitted

[LocutusOfBorg]

What version of Go are you using (go version)?

$ go version
1.13-rc2

Does this issue reproduce with the latest release?

yes

What operating system and processor architecture are you using (go env)?

Ubuntu devel, 19.10

What did you do?

trying to build the source code, I get

ok  	sync/atomic	0.047s
--- FAIL: TestAmbientCapsUserns (0.00s)
    exec_linux_test.go:667: fork/exec /tmp/gotest465803457: operation not permitted
FAIL
FAIL	syscall	0.033s

I suspect Ubuntu builders should ignore that test?

[ALTree]

Thanks for reporting this.

I doubt this is related to #12815. This look yet another variant of #30698. We already try to detect Kernel configurations that would make the test fail (CL 166460, CL 180877) but the current checks are possibly not exhaustive.

[ALTree]

Also, please note that this is not a build failure (i.e.: the code does not compile). The package compiles just fine, this is just a test failing. You can run make.bash instead of all.bash and the toolchain should be built without errors.

[LocutusOfBorg]

this is what we run...

        set -ex; \
                cd src; \
                export PATH="$(GOROOT)/bin:$$PATH"; \
                eval "$$(go tool dist env)"; \
                bash run.bash -k -no-rebuild;

[LocutusOfBorg]

interesting this fails also in pbuilder chroot configuration...

[LocutusOfBorg]

I can provide information if needed! Such as kernel configuration (Ubuntu 18.04 amd64 default one),
and steps to reproduce on a clean debian/ubuntu environment

[ALTree]

I can provide information if needed! Such as kernel configuration (Ubuntu 18.04 amd64 default one), and steps to reproduce on a clean debian/ubuntu environment

@LocutusOfBorg Yes please. It'll help with the investigation. Thanks.

[LocutusOfBorg]

on a Debian/Ubuntu system (I'm using ubuntu 18.04 LTS amd64)

pbuilder-dist sid create
pbuilder-dist sid login (remember the directory where the chroot is extracted)
pull-debian-source golang-1.13

copy the downloaded files into the chroot

go inside the chroot (the login command above does it)
cd golang-*
apt build-dep ../golang*dsc
dpkg-buildpackage

enjoy your failure!

Of course, inside the chroot you can install/play with whatever you want, install git, download stuff and so on...

[LocutusOfBorg]

inside an Ubuntu/Debian machine you probably just need to install "ubuntu-dev-tools"

[LocutusOfBorg]

This is my default kernel configuration

config-5.0.0-25-generic.txt

[longsleep]

This also fails on launchpad (see https://launchpadlibrarian.net/440240117/buildlog_ubuntu-xenial-amd64.golang-1.13_1.13-1longsleep1+xenial_BUILDING.txt.gz for example)