Contents
How to generate a vmcore file during a crash?
In the article Linux kernel crash simulation using kdump, I gave a brief idea as to how to generate a vmcore file during a crash or hangs. On this article, I will emphasize the analysis of a vmcore which has been generated and the tool ‘crash’ which can be used for advanced analysis.
Which is the best tool to analyze vmcore?
On this article, I will emphasize the analysis of a vmcore which has been generated and the tool ‘crash’ which can be used for advanced analysis. In a future article, I will elaborate on how to decode the detailed information given with the crash tool.
Where can I find the crash utility manual?
A good crash utility manual page can be found at people.redhat.com/anderson. Almost all info is available there. To be able to download the kernel-debuginfo package, you will need to activate the repo located at /etc/yum.repos.d
Why is vmcore not generated for a reboot?
Trigger points are not located in reboot function, this is the reason why vmcore is not generated for a reboot. The following conditions will execute a crash trigger point: If a hard lockup is detected and NMI watchdog is configured, the system will boot into the dump-capture kernel ( die_nmi () ).
What are the contents of / proc / vmcore file?
When the Kernel panics, it generates the /proc/vmcore file. Later we could use the makedumpfile utility to generate coredump using this vmcore file. What are the contents of this vmcore file? Does it contain Kernel Memory Region like Stack Area, Heap Area, Code Area and Constants? Does it also contains Process specific Information ?
Why is my vmcore missing a partial dump?
If the vmlinux file for the wrong kernel version is used then crash wont necessarily prevent it from loading. The ‘ [PARTIAL DUMP]’ tag means that some data is missing from the vmcore. In this case it is usually because the retrace-server system strips all zero pages from the vmcore in order to save space.