Fix for 5.2-BETA lockup problems

[Matt Smith]

Andre Oppermann wrote:
> Hello all,
> 
> I've found what probably is going wrong in tcp_hostcache.  The problem is me
> cutting corners (what goes around comes around...) in tcp_hc_insert when the
> bucket limit is reached.  I made the #if 0 too big and the bucket was not
> removed from the tailqueue when we hit the bucket limit.  A couple of lines
> later it is inserted again as head element which leads to an infinite loop
> either when the next lookup on the same bucket row is done, or when the
> the tcp_hc_purge function is run to timeout the entries.
> 
> Please try the attached patch which should fix it.
> 

This appears to have succesfully cured my lockup. I now have the 
original kernel config booted again with full inet6 etc and it's not 
locked up.

Regards, Matt.