test_ulimit_stack_small from ubuntu_qrt_kernel_security fails on I/J/M arm64k

[Kelsey Steele]

Note: I decided to split this report into two, let's track the test_030_mmap_min failure in bug 1931393 - PHLin

Test test_ulimit_stack_small from ubuntu_qrt_kernel_security is failing on Impish / Jammy ARM64k with:

  FAIL: test_ulimit_stack_small (__main__.KernelNonSecurityTest)
  Ensure small stack limits are enforced
  ----------------------------------------------------------------------
  Traceback (most recent call last):
    File "./test-kernel-security.py", line 3020, in test_ulimit_stack_small
      self.assertShellExitIn(expected, self._unpriv_cmd(["sh", "-c", "ulimit -s 1 && /bin/true"]))
    File "/home/ubuntu/autotest/client/tmp/ubuntu_qrt_kernel_security/src/qa-regression-testing/scripts/testlib.py", line 1218, in assertShellExitIn
      self.assertIn(rc, expected, msg + result + report)
  AssertionError: Got exit code 0, expected one of 139
  Command: 'sudo', '-u', 'ubuntu', 'sh', '-c', 'ulimit -s 1 && /bin/true'
  Output:

  ----------------------------------------------------------------------
  Ran 1 test in 0.016s

This is not failing on ARM64, but failing with generic-64k flavour instead.

[Original Bug Report]
Finding two failures in test-kernel-security.py from ubuntu_qrt_kernel_security fails on impish (test_ulimit_stack_small / test_030_mmap_min). These are found on previous kernels from Impish, so not considered a regression.

hosts: generic-64k dazzle and helo-kernel

test_ulimit_stack_small (__main__.KernelNonSecurityTest)
Ensure small stack limits are enforced ... FAIL

.....

test_030_mmap_min (__main__.KernelSecurityTest)
10/22 01:49:47 ERROR| utils:0153| [stderr] Low memory allocation respects mmap_min_addr ... (arm kernel with 64K pages configured (LP:#1931393) (65536) FAIL

.....

======================================================================
FAIL: test_ulimit_stack_small (__main__.KernelNonSecurityTest)
Ensure small stack limits are enforced
----------------------------------------------------------------------
Traceback (most recent call last):
  File "./test-kernel-security.py", line 3014, in test_ulimit_stack_small
    self.assertShellExitIn(expected, self._unpriv_cmd(["sh", "-c", "ulimit -s 1 && /bin/true"]))
  File "/home/ubuntu/autotest/client/tmp/ubuntu_qrt_kernel_security/src/qa-regression-testing/scripts/testlib.py", line 1218, in assertShellExitIn
    self.assertIn(rc, expected, msg + result + report)
AssertionError: Got exit code 0, expected one of 139
Command: 'sudo', '-u', 'ubuntu', 'sh', '-c', 'ulimit -s 1 && /bin/true'
Output:

======================================================================
FAIL: test_030_mmap_min (__main__.KernelSecurityTest)
Low memory allocation respects mmap_min_addr
----------------------------------------------------------------------
Traceback (most recent call last):
  File "./test-kernel-security.py", line 285, in test_030_mmap_min
    mmap_limit = self._test_sysctl_value('vm/mmap_min_addr', wanted, "is wine or qemu-kvm-extras-static installed?")
  File "/home/ubuntu/autotest/client/tmp/ubuntu_qrt_kernel_security/src/qa-regression-testing/scripts/testlib.py", line 1269, in _test_sysctl_value
    self.assertEqual(value, expected, report)
AssertionError: /proc/sys/vm/mmap_min_addr is not 65536: 32768 (is wine or qemu-kvm-extras-static installed?)

----------------------------------------------------------------------
Ran 125 tests in 26.120s

FAILED (failures=2)

[Thadeu Lima de Souza Cascardo (cascardo)]

https://code.launchpad.net/~cascardo/qa-regression-testing/+git/qa-regression-testing/+merge/435590

[Po-Hsu Lin (cypressyew)]

Throw this back to new, as the fix above is introducing regression to older kernels and reverted.

[Andrei Gherzan (agherzan)]

I have hit this on focal:linux-hwe-5.15 and hinted referencing this bug.

https://code.launchpad.net/~canonical-kernel-team/+git/rt-hints/+merge/441339

SRU Cycle: 2023.03.20
Series: focal
Package: linux-hwe-5.15
Version: 5.15.0-70.77~20.04.1
Cloud: openstack
Instance: cpu4-ram4-disk20

[Po-Hsu Lin (cypressyew)]

Found with j-lowlatency-hwe-6.5.0-14.14.1~22.04.1 on lowlatency-64k ARM64 openstack instance.