My eyes feel like a kaleidoscope after less than 20 minutes of reading! On Thu, Dec 10, 2015 at 8:38 PM, Michael Havens wrote: > thank you so much Jerry. That was quite helpful. made me realize that I > was getting in way over my head! So now I am reading one of the resources > . > > On Thu, Dec 10, 2015 at 6:30 PM, Jerry Snitselaar > wrote: > >> On Thu Dec 10 15, Michael Havens wrote: >> >>> I want to see why my kernel panics (if it does) so I was lead to: >>> [1]https://help.ubuntu.com/lts/serverguide/kernel-crash-dump.html >>> sudo cat /etc/default/kdump-tools>> USE_KDUMP=1 >>> Will the above line append USE_KDUMP=1 to kdump-tools. >>> -- >>> :-)~MIKE~(-: >>> >>> References >>> >>> 1. https://help.ubuntu.com/lts/serverguide/kernel-crash-dump.html >>> >> >> I've never played with it on Ubuntu. >> >> You will need the crashkernel parameter on the boot line so memory >> gets set aside to the kdump kernel memory image. >> >> Also you will need to reboot, so it builds the image if you haven't >> already done so (according to that page, Red Hat/Fedora does the same >> thing). >> >> You will probably need to install debug symbols for the kernel in >> question. Not sure how that is done for Ubuntu. >> >> It doesn't look like it explains it on that page, but look to see if >> there is a kdump.conf file in /etc, that will probably need to be >> modified to suit your system. >> >> Once you have it up and running, when the system panics it will >> jump to the kdump kernel, bring that up, harvest an image of the >> memory, then reboot the system and come up again on the regular >> kernel. >> >> Then you would go to /var/crash or wherever it is configured to >> place the vmcore file, and then: >> >> crash /boot/System-map-for-kernel >> /lib/modules/debug/lib/modules/kernel-rel/vmlinux vmcore >> >> The vmlinux part would be whatever location it installed the kernel image >> which still has >> debug symbols not stripped. >> >> Some commands: >> >> bt - prints backtrace of the current process >> bt -a - prints backtrace for processes on all cpus >> bt -f - prints the contents of the stack with the backtrace >> >> help - will list available commands and help command, will print >> out detailed help for the commands. >> >> log - dumps the in memory system log (what you would normally see >> with dmesg command) >> >> set # - set focus to certain pid >> set -c # - set focus to certain cpu >> dis function-name - provides disassembled code for the function given >> >> mod - load symbols for a module >> >> rd - read contents of memory >> struct - display a struct, (with address provided as well dumps out >> formatted struct with values) >> >> >> Unless you are familiar with kernel internals and assembly code, what >> you'll probably want is to: >> >> set scroll off >> log >> >> And look at the end of the log to find the message where it paniced, >> and post those contents somewhere. If it is a distro kernel your best >> bet will be contacting those folks. >> >> Jerry >> >> --------------------------------------------------- >>> PLUG-discuss mailing list - PLUG-discuss@lists.phxlinux.org >>> To subscribe, unsubscribe, or to change your mail settings: >>> http://lists.phxlinux.org/mailman/listinfo/plug-discuss >>> >> >> --------------------------------------------------- >> PLUG-discuss mailing list - PLUG-discuss@lists.phxlinux.org >> To subscribe, unsubscribe, or to change your mail settings: >> http://lists.phxlinux.org/mailman/listinfo/plug-discuss >> > > > > -- > :-)~MIKE~(-: > -- :-)~MIKE~(-: