cve test from ubuntu_ltp will failed to fork on B-KVM

Not sure if this has something to do with another timeout issue in controller test, the test will not get started at all:
        08/06 06:14:10 INFO |ubuntu_ltp:0088| Checking virt-what to see if we need to set LTP_TIMEOUT_MUL for memcg_test_3...
        08/06 06:14:10 INFO |ubuntu_ltp:0091| Running in VM, set timeout multiplier LTP_TIMEOUT_MUL>1 (lp:1836694) for memcg_test_3
        08/06 06:29:32 ERROR| test:0414| Exception escaping from test:
        Traceback (most recent call last):
        File "/home/ubuntu/autotest/client/shared/test.py", line 411, in _exec
        _call_test_function(self.execute, *p_args, **p_dargs)
        File "/home/ubuntu/autotest/client/shared/test.py", line 830, in _call_test_function
        raise error.UnhandledTestFail(e)
        UnhandledTestFail: Unhandled OSError: [Errno 11] Resource temporarily unavailable
        Traceback (most recent call last):
        File "/home/ubuntu/autotest/client/shared/test.py", line 823, in _call_test_function
        return func(*args, **dargs)
        File "/home/ubuntu/autotest/client/shared/test.py", line 291, in execute
        postprocess_profiled_run, args, dargs)
        File "/home/ubuntu/autotest/client/shared/test.py", line 212, in _call_run_once
        self.run_once(*args, **dargs)
        File "/home/ubuntu/autotest/client/tests/ubuntu_ltp/ubuntu_ltp.py", line 103, in run_once
        utils.run(cmd, ignore_status=True, verbose=False)
        File "/home/ubuntu/autotest/client/shared/utils.py", line 914, in run
        stderr_level=get_stderr_level(stderr_is_expected)),),
        File "/home/ubuntu/autotest/client/shared/utils.py", line 128, in __init__
        stdin=stdin)
        File "/usr/lib/python2.7/subprocess.py", line 394, in __init__
        errread, errwrite)
        File "/usr/lib/python2.7/subprocess.py", line 938, in _execute_child
        self.pid = os.fork()
        OSError: [Errno 11] Resource temporarily unavailable
~

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: linux-image-4.15.0-1039-kvm 4.15.0-1039.39
ProcVersionSignature: User Name 4.15.0-1039.39-kvm 4.15.18
Uname: Linux 4.15.0-1039-kvm x86_64
ApportVersion: 2.20.9-0ubuntu7.7
Architecture: amd64
Date: Tue Aug 6 11:51:21 2019
SourcePackage: linux-kvm
UpgradeStatus: No upgrade log present (probably fresh install)