Messages in this thread | | | Date | Wed, 5 Oct 2011 18:16:26 +0200 | From | Borislav Petkov <> | Subject | Re: [Patch 1/4][kernel][slimdump] Add new elf-note of type NT_NOCOREDUMP to capture slimdump |
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On Wed, Oct 05, 2011 at 12:00:38PM -0400, Valdis.Kletnieks@vt.edu wrote: > On Wed, 05 Oct 2011 11:52:17 EDT, Vivek Goyal said: > > > I am assuming that basic MCE error messages are available in kernel log. > > They're not in the kernel log if it's an MCE that causes the kernel to declare > a panic. There's some MCE's that you can retry the operation and continue, and > some that you can get away with poisoning a page, killing the process, and rest > of the system is OK. But some you really need to roll over and die because you > can't guarantee kernel integrity anymore. > > And at that point, those messages are never gonna make it to syslogd and onto > disk.
AFAICT, and for the sake of getting the MCE info, arguably one could look for log_buf in the vmcore of the old kernel and try to find the last lines in the kernel log ringbuffer. They should be the MCE error information from the do_machine_check MCE handler.
This all assuming of course we've managed to dump vmcore successfully by sidestepping the landmines :-).
-- Regards/Gruss, Boris.
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