Subject: Re: kernel panic in fib_rules_lookup [2.6.27.7 vendor-patched]

From: Joe Buehler <[email-masked]>
Date: Sat, 23 Oct 2010 11:40:35 -0400

Eric Dumazet wrote:
>
> David Daney added a nudge_writes(), actually doing a "syncw"
> instruction, and this seems to be the smp_wmb() this platform should be
> using in the first place, not a pure compiler barrier (barrier()) 
>
> So Joe, you might want to change the smp_wmb() call in
> rcu_assign_pointer() by the nudge_writes() call, and see what happens...
>
>
>   

I think Daney is Cavium's Octeon LINUX guru from the posts I've seen so
he would definitely know the platform.  I'm not sure I quite understand
what you are saying but it sounds as though you are saying that smp_wb
is not doing a syncw and that sounds *totally* broken -- snycw is what
the low-level Cavium SDK uses for memory barriers all over the place.

Joe Buehler