/proc/self/stack does not exist in kvm kernel, causing failures in kernel security test

[Po-Hsu Lin]

Linux larry 4.18.0-1005-kvm #5-Ubuntu SMP Thu Nov 15 20:22:03 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

# ls /proc/self/stack
ls: cannot access '/proc/self/stack': No such file or directory

Thus:
FAIL: test_095_kernel_symbols_missing_proc_self_stack (__main__.KernelSecurityTest)
kernel addresses in /proc/self/stack are zeroed out
----------------------------------------------------------------------
Traceback (most recent call last):
File "./test-kernel-security.py", line 1352, in test_095_kernel_symbols_missing_proc_self_stack
self._check_pK_files(self._095_kernel_symbols_missing_proc_self_stack, expected=expected)
File "./test-kernel-security.py", line 1199, in _check_pK_files
test_function(expected_restricted)
File "./test-kernel-security.py", line 1296, in _095_kernel_symbols_missing_proc_self_stack
'/proc/self/stack does not exist')
AssertionError: /proc/self/stack does not exist

[Po-Hsu Lin (cypressyew)]

I think it's the config was not enabled on all the KVM kernels:
# CONFIG_STACKTRACE is not set

This issue should be fixed in the QRT test suite.

[Colin Ian King (colin-king)]

..or perhaps enable that config option for those kernels?

[Po-Hsu Lin (cypressyew)]

Yeah that would be another option for maintainer to decide. Not sure if we will this debug feature for KVM kernels.

[Steve Beattie (sbeattie)]

Regardless of whether the linux-kvm maintainer decides to enable this option, the test should not fail if the option is disabled. I'll fix qrt to check for CONFIG_STACKTRACE.

Thanks!

[Steve Beattie (sbeattie)]

The qa-regression-testing side of things is fixed in commit https://git.launchpad.net/qa-regression-testing/commit/?id=b5cea2f0466f932a86fe31ac3a3ff51dcb99c95e .

Thanks!

[Thadeu Lima de Souza Cascardo (cascardo)]

By the way, on 4.19, this is now only readable by root. So, now returns EACCESS when user tries to read it.

$ cat /proc/self/stack
cat: /proc/self/stack: Permission denied

f8a00cef17206ecd1b30d3d9f99e10d9fa707aa7 proc: restrict kernel stack dumps to root

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is missing log files that will aid in diagnosing the problem. While running an Ubuntu kernel (not a mainline or third-party kernel) please enter the following command in a terminal window:

apport-collect 1805105

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

[Po-Hsu Lin (cypressyew)]

On a second thought
As this test has been corrected to cope with a kernel without CONFIG_STACKTRACE enabled.
I think this should be enough to close this bug.

If we ever need a discussion / tracking bug for enabling CONFIG_STACKTRACE or not, we can have a new bug for it.

I will close this bug.
Thanks!