KernelNonSecurityTest.test_10_bad_syscall_returns_ENOSYS from ubuntu_qrt_kernel_security failed on Noble GCP N2D instances

[Po-Hsu Lin]

Issue found on Google N2D instances since sru-20240429 with Noble 6.8.0-32.32

KernelNonSecurityTest.test_10_bad_syscall_returns_ENOSYS failed with:
 Running 'python3 ./test-kernel-security.py -v KernelNonSecurityTest.test_10_bad_syscall_returns_ENOSYS'
 Running test: './test-kernel-security.py' distro: 'Ubuntu 24.04' kernel: '6.8.0-36.36.1 (Ubuntu 6.8.0-36.36.1-lowlatency 6.8.4)' arch: 'amd64' init: 'systemd' uid: 0/0 SUDO_USER: 'ubuntu')
 test_10_bad_syscall_returns_ENOSYS (__main__.KernelNonSecurityTest.test_10_bad_syscall_returns_ENOSYS)
 syscall(666666) returns ENOSYS (LP: #339743) ... FAIL

 ======================================================================
 FAIL: test_10_bad_syscall_returns_ENOSYS (__main__.KernelNonSecurityTest.test_10_bad_syscall_returns_ENOSYS)
 syscall(666666) returns ENOSYS (LP: #339743)
 ----------------------------------------------------------------------
 Traceback (most recent call last):
   File "/home/ubuntu/autotest/client/tmp/ubuntu_qrt_kernel_security/src/qa-regression-testing/scripts/./test-kernel-security.py", line 3036, in test_10_bad_syscall_returns_ENOSYS
     self.assertShellExitEquals(expected, self._unpriv_cmd(["./bad-syscall"]))
   File "/home/ubuntu/autotest/client/tmp/ubuntu_qrt_kernel_security/src/qa-regression-testing/scripts/testlib.py", line 1331, in assertShellExitEquals
     self.assertEqual(expected, rc, msg + result + report)
 AssertionError: 0 != -11 : Got exit code -11, expected 0
 Command: 'sudo', '-u', 'ubuntu', './bad-syscall'
 Output:

 ----------------------------------------------------------------------
 Ran 1 test in 0.187s

 FAILED (failures=1)

$ sudo -u ubuntu ./bad-syscall
Segmentation fault
$ echo $?
139

And this failure will trigger:
2024-07-08T03:47:09.719619+00:00 n-l-gen-6-8-n2dstd2-u-qrt-krn-security kernel: traps: bad-syscall[5430] general protection fault ip:5e0f965b80aa sp:7ffdf3cf71d0 error:402 in bad-syscall[5e0f965b8000+1000]

Which leads to the sut-scan failure as the "kernel: traps:" pattern was found.