[Ksummit-2012-discuss] [ATTEND] kernel core dump and "dying breath"

Cong Wang xiyou.wangcong at gmail.com
Fri Jun 22 02:58:36 UTC 2012

On 06/22/2012 01:20 AM, Tim Bird wrote:
> For embedded, where the kernel loads into identical memory locations
> every time, I've wondered if there couldn't be some trivial way
> to preserve the log buffer position across the boot, and have each
> boot append it's messages starting where the last one left off.
> So a dmesg would show messages from the current and last (and
> possibly even previous) boots.  It wouldn't be difficult to
> find the start positions (to determine which messages go with
> which invocations).

I think this is true on x86 too, at least on a specific machine the 
memory location of kernel is always the same (unless pass different 
cmdline, of course).

I remember someone from Red Hat submitted a patchset to implement what 
you described above (I need to dig the email archives to find the link), 
to make machines that don't have NVRAM still be able to store the dmesg 
across a reboot.

As James Bottomley mentioned in this thread, NVRAM becomes more popular 
today, but I still haven't seen any x86 machines with NVRAM available so 
far. :(


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