So, the difference between 4.19.19-188.8.131.52.xcpng8.1 and 4.19.19-184.108.40.206.xcpng8.1 is two patches meant to reduce the performance overhead of the CROSSTalk vulnerability mitigations.
So, assuming from @delaf's test results that one of those patches introduced the memory leak, I have built
Now here are the tests that you can do:Reproduce @delaf's findings by running kernel-4.19.19-220.127.116.11.xcpng8.1: no more memory leaks? Test this kernel I built with patch 53 disabled: https://nextcloud.vates.fr/index.php/s/YXWCSEwo8SWkfAZ Test this kernel I built with patch 62 disabled: https://nextcloud.vates.fr/index.php/s/arj5YfdrkjMKbBy
If one of the patches is the cause of the memory leak, then one of the last two should still cause a memory leak and the other one not.