panic on one cpu leaves others running...

Robert Watson rwatson at
Thu Apr 8 09:23:04 PDT 2004

On Thu, 8 Apr 2004, Brian F. Feldman wrote:

> Robert Watson <rwatson at> wrote:
> > 
> > panic: m 0 so->so_rcv.sb_cc 17
> > at line 860 in file ../../../kern/uipc_socket.c
> What made you receive that panic?  I remember having that exact panic
> (sb_cc size being a little different, obviously) months ago... and
> having it disappear.  Did you have networking out from Giant where it
> shouldn't have yet been? ;) 

This is running without Giant over most of the network stack.  However,
I'm still working on tracking down the source of the problem -- I'm
beginning to wonder if it's not an existing race opened up by releasing
locks in areas where only memory allocations required sleeping would have
opened the race previously.  I got this panic during local UNIX domain
socket IPC between the sshd bits.  I suspect what's going on, but need to
look in more detail, is that something is messed up relating to control
mbufs -- I.e., ancillary data transfer.  If you're interested in taking a
look at the current work-in-progress, take a look at the rwatson_netperf
branch in perforce, or at:

I can also add you to the CC list for new patch versions if you like.
Pretty shortly, I'll be sending them to arch@ instead, but I need to
resolve a few problems in socket locking (including this one).

Robert N M Watson             FreeBSD Core Team, TrustedBSD Projects
robert at      Senior Research Scientist, McAfee Research

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

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