2023-07-18T06:01:31+0200 SUBDEBUG Upgrade: java-1.8.0-openjdk-1:1.8.0.372.b07-6.fc37.x86_64 2023-07-18T06:01:32+0200 SUBDEBUG Upgraded: java-1.8.0-openjdk-1:1.8.0.362.b09-2.fc37.x86_64 The systems that had those freezes ( 2 atm ) have in common: Xen VM 1 cpu core > 2 GB ram active java apps same CPU Freeze message after rebooting with 100% cpu load while system is stuck freezes started today ~24 after the upgrade system had a 90+-1 day uptime before, and YEARS in this vm setup before those 90 Days ( which was the upgrade date of the fedora os ) as soon, as we changed the vm's to 2 cpu cores, freezing was gone. no hints in journal and/or /v/l/messages ( which sometimes survives hard reboots better than the system journal). Possibilities: a) it has nothing to do with java/update at all b) it has to do with the java 1.8 update, as java apps are running constantly. c) someone messes with the system via network ( kernel dos? ) Please keep this bugreport open for tracking. IF something changes, we get more infos, we will add those here.
After three weeks of java update in action, servers with a lot of java activity just freeze or crash. i.e. today at 15:05 tomcat (java was / 2 cores) just froze without any error message and 3 hours later the entire kernel crashed with a cpu freeze in a java process. I THINK, as this happend already some years ago, the actual java code messes with the memory management and the kernel ends up in a bad state trying to work throu the mem-structures. - More memory will delay the process - more cpu cores compensate the freeze and give opportunities to fix the issue by the kernel itself.