Kernel panic reading - Can you tell what triggered it?

[D. Hugh Redelmeier]

| From: William Muriithi <william.muriithi-Re5JQEeQqe8AvxtiuMwx3w at public.gmane.org>
| 
| I am sharing this as I am not sure what triggered it and therefore
| have not figured how to fix it.  This is the third time the system has
| crashed and the system is just just running vertica.  Vertica claim
| they do not have any kernel level module - I feel like they are not
| truthful but have no evidence to prove them wrong.  If they are
| telling the truth, then RHEL6 does have a bug would like to post on
| RedHat bugzilla

Makes sense.

My default position would be to trust Vertica.

| The most interesting part:-
| 
| BUG: Bad page state in process vertica  pfn:6db6d9adbf6d47af
| page:ffff8801dfe7ae48 flags:000000000000001f count:36561488
| mapcount:-5631 mapping:ffff8801dfe7ae60 index:ffff8801dfe7ae60

I don't know what a mapcount is, but its name suggests that it ought
to be non-negative.

Googling for "mapcount negative" (no quotes) gets me mostly items
from 2006.  One exception is a Zen bug report from last month:
  <http://www.bullopensource.org/xen/bugs_reports.html#TocId09212006M>
I didn't look at it so I don't know if it is at all like your problem.

| (Tainted: G        W  ----------------  )
| Pid: 682, comm: vertica Tainted: G        W  ----------------

According to line 222 on of
  <http://www.mjmwired.net/kernel/Documentation/oops-tracing.txt>

- G means: all modules are GPL licensed, or compatibly licensed.
  In other words, not tainted by loading an off-licensed module

- W means that a warning has previously been issued by the kernel

I infer that kernel hacks wish to look at the first warning because
once a warning happens, all bets are off.


| Look like the iptables module also have issues, but I doubt RedHat
| would would look at it as the kernel claim to be tainted.

Would those be the earlier warnings that set the W taint flag?
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