For the record, Guilherme and I concluded that when dumping a kexec kernel, there may be leftover memory from the previous kernel which causes the dump to be corrupted. That was after I ran some tests that showed that when booting a 3.13.0-137, kexecing a 3.13.0-85, then dumping, the dump would contain 3.13.0-137 versions. And Guilherme confirmed that kexec was used to boot kernels once in a while during the tests.
As the test results from Guilherme include boots with kexec and without it, and the results were not consistent, the suggestion is that multiple dumps be taken only when cold booting a 3.13 kernel, using makedumpfile shipped from trusty-updates. And that those be verified with crash. Cascardo. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to makedumpfile in Ubuntu. https://bugs.launchpad.net/bugs/1785686 Title: makedumpfile not able to use compression in trusty kernel 3.13 (fallback to 'cp') Status in makedumpfile package in Ubuntu: New Bug description: When kdumping in 3.13.0-85-generic, using the sysrq trigger "echo c > /proc/sysrq-trigger", I got the following messages: The kernel version is not supported. The created dumpfile may be incomplete. check_release: Can't get the kernel version. makedumpfile Failed. * kdump-config: makedumpfile failed, falling back to 'cp' * kdump-config: saved vmcore in /var/crash/201808061812 * running makedumpfile --dump-dmesg /proc/vmcore /var/crash/201808061812/dmesg.201808061812 The kernel version is not supported. The created dumpfile may be incomplete. check_release: Can't get the kernel version. The vmcore was generated, but it is RAM-sized (in my case, 64G). Compression failed. Thanks, Guilherme ProblemType: Bug DistroRelease: Ubuntu 14.04 Package: makedumpfile 1.5.5-2ubuntu1.6 ProcVersionSignature: Ubuntu 3.13.0-85.129-generic 3.13.11-ckt36 Uname: Linux 3.13.0-85-generic x86_64 ApportVersion: 2.14.1-0ubuntu3.29 Architecture: amd64 Date: Mon Aug 6 18:32:06 2018 ProcEnviron: TERM=screen PATH=(custom, no user) XDG_RUNTIME_DIR=<set> LANG=en_US.UTF-8 SHELL=/bin/bash SourcePackage: makedumpfile UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/makedumpfile/+bug/1785686/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
