CC @LK4D4

@laboger Could you check CONFIG_USER_NS in your kernel config, pls?
EDIT: You obviously have it, because other tests passing.

I suppose it might be because of SeLinux rules. Could you try to disable it and rerun? Thanks!

CONFIG_USER_NS=y
I tried:
setenforce 0
getenforce
Permissive

tests still failed as before.

I set SELINUX to disabled and rebooted.
getenforce
Disabled

tests still failed as before.

I also tried a fedora21 ppc64le system and that passes with selinux enabled. Only RHEL 7.2 fails.

@laboger Can you try to run tests from root? I'll try to setup VM with rhel 7.2 myself to look at problem.
ping @mrunalp

Same failures when run as root.

@laboger Are you sure that tests names not different? Those tests should be skipped with root.

Oops sorry I wasn't expecting the failing testnames to be different and didn't look closely.

Here's my screen output:
[root@willow2 syscall]# pwd
/home/boger/golang/gitsrc/latest/go/src/syscall
[root@willow2 syscall]# go test .
--- FAIL: TestCloneNEWUSERAndRemapRootDisableSetgroups (0.00s)
exec_linux_test.go:57: Cmd failed with err fork/exec /usr/bin/whoami: invalid argument, output:
--- FAIL: TestCloneNEWUSERAndRemapRootEnableSetgroups (0.00s)
exec_linux_test.go:57: Cmd failed with err fork/exec /usr/bin/whoami: invalid argument, output:
--- FAIL: TestEmptyCredGroupsDisableSetgroups (0.00s)
exec_linux_test.go:105: fork/exec /usr/bin/whoami: invalid argument
FAIL
FAIL syscall 0.018s
[root@willow2 syscall]# pwd
/home/boger/golang/gitsrc/latest/go/src/syscall
[root@willow2 libgo]# which go
/home/boger/golang/gitsrc/latest/go/bin/go

And with gccgo, I have to hit Ctrl-C to get the output if I run as root:

root@willow2 libgo]# make syscall/check
^C--- FAIL: TestCloneNEWUSERAndRemapRootDisableSetgroups (0.00s)
testing.go:284: Cmd failed with err fork/exec /usr/bin/whoami: invalid argument, output:
--- FAIL: TestCloneNEWUSERAndRemapRootEnableSetgroups (0.00s)
testing.go:284: Cmd failed with err fork/exec /usr/bin/whoami: invalid argument, output:
/home/boger/gccgo.work/trunk/bld/../src/libgo/testsuite/gotest: line 625: kill: (7658) - No such process

The unshare system call is returning EINVAL.

So, it's bug in RHEL, which must be fixed. I'm glad that we helped with finding it :)

mount namespace isn't supported with user namespace in RHEL 7.2 as some patches haven't been backported. So, this is expected behavior for now.

@mrunalp I don't see mount namespaces in tests. Maybe without mount namespaces?

@LK4D4 Let me try that. I tried with everything in my testing.

@LK4D4 You are right. That fails as well. I am following up with RHEL engineers.

One has to enable user namespace support with a kernel boot option as it is in tech preview right now. After adding user_namespace.enable=1 as a boot option unshare -Ur works for me.

From @mrunalp's comments it sounds like this is not a Go bug.

(We could of course disable the test, if this is important to any developers on RHEL 7.2 and we can detect that case.)