Panic: UDP header not in one mbuf

[Sven Willenberger]

Matthew Dillon wrote:
:I am not sure if this is the proper mailing list for this question; if
:not, please direct me accordingly.
:
:On a DragonFly 1.1-Current machine (cvsupped and built 8/19/2004) I
:receive the following output after a panic (with DDB enabled in kernel):
:
:panic: UDP header not in one mbuf
:...
:
:I have been having issues of this nature for a while - I suspect an
:issue I am having with bind (named) crashing is related to this.
:
:The machines are Supermicro 6013P-8 with dual P4 (Xeon) procs. ACPI is
:disabled, HTT is not. The machines process a decent volume (65k pieces
:daily) of email and use mimedefang/spamassassin/sendmail along with a
:local caching instance of named.
    Sven, please try this patch.  After examining the code path I found
    a hole where an embedded ip_len which is smaller then the actual
    packet survives the length test in ip_demux(), which means it can hit
    the assertion in udp_input().
						-Matt

Index: ip_demux.c
===================================================================
RCS file: /cvs/src/sys/netinet/ip_demux.c,v
retrieving revision 1.26
diff -u -r1.26 ip_demux.c
--- ip_demux.c	3 Aug 2004 00:04:13 -0000	1.26
+++ ip_demux.c	23 Aug 2004 21:21:14 -0000
<snip>

So far the patch seems to be working, machines with it have been up and 
running since applying it. Hard to say if the packet that caused the 
panic has cropped up again, but it usually would have surfaced as a 
panic within about a week.

Thanks again.