log_check / kernel_tainted test from ubuntu_boot failed on ARM64 node starmie-kernel with 5.8 generic-64k kernel (failed with flag 512)

[Po-Hsu Lin]

Found on Focal/hwe-5.8 5.8.0-45.51~20.04.1 generic-64k, host: starmie-kernel

Though it's instead "ERROR: kernel tainted flag != 0: 512"

03/11 04:40:30 INFO |ubuntu_boo:0042| Checking kernel tainted flags in /proc/sys/kernel/tainted
03/11 04:40:30 INFO |ubuntu_boo:0046| ERROR: kernel tainted flag != 0: 512
03/11 04:40:30 INFO |ubuntu_boo:0046|
03/11 04:40:30 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 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_boot/ubuntu_boot.py", line 59, in run_once
 raise error.TestFail()
 TestFail

This flag was caused by a WARNING in the boot dmesg:
WARNING: CPU: 0 PID: 1 at arch/arm64/kernel/efi.c:28 efi_create_mapping+0x80/0x170

Which is causing failure in the log_check test.

[Po-Hsu Lin (cypressyew)]

This can be found on Groovy 5.8 generic-64k kernel on starmie-kernel as well. And it can be reproduced with the generic-64k kernel in -updates (5.8.0-44-generic-64k).

Interesting part is that this issue does not exist in 5.8 generic-arm64 kernel, just in this generic-64k kernel on this specific node.

This is triggered by the following code in efi.c:
        if (WARN_ONCE(!PAGE_ALIGNED(md->phys_addr),
                      "UEFI Runtime regions are not aligned to 64 KB -- buggy firmware?"))

[Po-Hsu Lin (cypressyew)]

Found on Xenial 4.4 with intel amd64 node spitfire, with warning pattern:
kernel: [ 0.329147] WARNING: CPU: 0 PID: 1 at /build/linux-t9uCyM/linux-4.4.0/arch/x86/events/intel/core.c:3656 intel_pmu_init+0xc48/0xe03()