msgstress04 test in ubuntu_ltp_syscalls failed with X-AWS

The msgstress test will failed to kill child processes, and leave many processes running after this test has finished.

10:28:07 DEBUG| [stdout] <<<test_start>>>
10:28:07 DEBUG| [stdout] tag=msgstress04 stime=1533896887
10:28:07 DEBUG| [stdout] cmdline="msgstress04"
10:28:07 DEBUG| [stdout] contacts=""
10:28:07 DEBUG| [stdout] analysis=exit
10:28:07 DEBUG| [stdout] <<<test_output>>>
10:28:08 DEBUG| [stdout] msgstress04 0 TINFO : Found 32000 available message queues
10:28:08 DEBUG| [stdout] msgstress04 0 TINFO : Using upto 16285 pids
10:28:09 DEBUG| [stdout] Fork failure in the second child of child group 188
10:28:09 DEBUG| [stdout] Fork failure in the first child of child group 189
10:28:09 DEBUG| [stdout] Fork failure in the first child of child group 190
10:28:09 DEBUG| [stdout] Fork failure in the first child of child group 191
10:28:09 DEBUG| [stdout] Fork failure in the second child of child group 192
10:28:09 DEBUG| [stdout] Fork failure in the first child of child group 193
10:28:09 DEBUG| [stdout] Fork failure in the first child of child group 194
10:28:09 DEBUG| [stdout] Fork failure in the first child of child group 195
10:28:09 DEBUG| [stdout] Fork failure in the first child of child group 205
10:28:09 DEBUG| [stdout] Fork failure in the first child of child group 237
10:28:09 DEBUG| [stdout] Fork failure in the second child of child group 274
10:28:09 DEBUG| [stdout] Fork failure in the first child of child group 275
10:28:09 DEBUG| [stdout] Fork failure in the first child of child group 276
10:28:09 DEBUG| [stdout] Fork failure in the first child of child group 285
10:28:09 DEBUG| [stdout] Fork failure in the first child of child group 286
10:28:09 DEBUG| [stdout] Fork failure in the first child of child group 287
10:28:09 DEBUG| [stdout] Fork failure in the first child of child group 288
10:28:09 DEBUG| [stdout] Fork failure in the first child of child group 289
10:28:09 DEBUG| [stdout] Fork failure in the first child of child group 290
10:28:09 DEBUG| [stdout] Fork failure in the first child of child group 298
10:28:09 DEBUG| [stdout] Fork failure in the first child of child group 299
10:28:09 DEBUG| [stdout] Fork failure in the first child of child group 301
10:28:09 DEBUG| [stdout] Fork failure in the second child of child group 294
10:28:09 DEBUG| [stdout] Fork failure in the first child of child group 226
10:28:10 DEBUG| [stdout] Fork failure in the first child of child group 335
10:28:11 DEBUG| [stdout] msgstress04 1 TFAIL : msgstress04.c:220: Child exit status = 1
10:28:11 DEBUG| [stdout] <<<execution_status>>>
10:28:11 DEBUG| [stdout] initiation_status="ok"
10:28:11 DEBUG| [stdout] duration=4 termination_type=exited termination_id=1 corefile=no
10:28:11 DEBUG| [stdout] cutime=23 cstime=14
10:28:11 DEBUG| [stdout] <<<test_end>>>
10:28:12 DEBUG| [stdout] msgstress04 1 TBROK : msgstress04.c:365: Kill failed to kill child 0

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: linux-image-4.4.0-1064-aws 4.4.0-1064.74
ProcVersionSignature: User Name 4.4.0-1064.74-aws 4.4.140
Uname: Linux 4.4.0-1064-aws x86_64
ApportVersion: 2.20.1-0ubuntu2.18
Architecture: amd64
Date: Mon Aug 13 06:32:47 2018
Ec2AMI: ami-529fb82a
Ec2AMIManifest: (unknown)
Ec2AvailabilityZone: us-west-2b
Ec2InstanceType: x1e.xlarge
Ec2Kernel: unavailable
Ec2Ramdisk: unavailable
SourcePackage: linux-aws
UpgradeStatus: No upgrade log present (probably fresh install)