Is socket buffer locking as questionable as it seems?

[Brian F. Feldman]

Sam Leffler <sam at errno.com> wrote:
> On Friday 03 October 2003 10:38 pm, Brian Fundakowski Feldman wrote:
> > I keep getting these panics on my SMP box (no backtrace or DDB or crash
> > dump of course, because panic() == hang to FreeBSD these days):
> > panic: receive: m == 0 so->so_rcv.sb_cc == 52
> > From what I can tell, all sorts of socket-related calls are "MP-safe"
> > and yet never even come close to locking the socket buffer.  From
> > what I can tell, the easiest way for this occur would be sbrelease()
> > being called from somewhere that it's supposed to, but doesn't, have
> > sblock().  Has anyone seen these, or a place to start looking?  Maybe
> > a way to get panics to stop hanging the machine?  TIA if anyone has
> > some enlightenment.
> 
> Haven't seen anything on my SMP test box.  As Robert has already said sockets 
> are still implicitly locked by Giant.  You need to provide more information 
> like what version you are running and what your system is doing when the 
> panic occurs.
> 
> FWIW panic does not hang for me so you might first try to figure out why 
> that's occuring.

I turned off sync on panic so maybe I'll be okay now.  That never, ever, 
worked for me starting a couple years ago and I forgot I had it disabled 
locally.  I see it immediately on boot and I couldn't tell you why; this is 
a NAT box, and a million other things.  I'm running the most current current 
I can possibly run, of course.

-- 
Brian Fundakowski Feldman                           \'[ FreeBSD ]''''''''''\
  <> green at FreeBSD.org                               \  The Power to Serve! \
 Opinions expressed are my own.                       \,,,,,,,,,,,,,,,,,,,,,,\