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Date:      Thu, 26 Sep 2002 10:35:47 -0700 (PDT)
From:      al <bsdal@otterhole.ods.org>
To:        freebsd-gnats-submit@FreeBSD.org
Subject:   kern/43396: repeatable kernel panic in if_xl.c:xl_newbuf:MCLGET
Message-ID:  <200209261735.g8QHZlGu016682@www.freebsd.org>

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>Number:         43396
>Category:       kern
>Synopsis:       repeatable kernel panic in if_xl.c:xl_newbuf:MCLGET
>Confidential:   no
>Severity:       critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Thu Sep 26 10:40:08 PDT 2002
>Closed-Date:
>Last-Modified:
>Originator:     al
>Release:        4.7-RC Sep 24
>Organization:
>Environment:
FreeBSD XXXX 4.7-RC FreeBSD 4.7-RC #12: Tue Sep 24 13:30:20 EDT 2002 
 YYYY@XXXX:/play/obj/usr/src/sys/XXXX  i386 (not Generic)
xl0: <3Com 3c905C-TX Fast Etherlink XL> port 0xb800-0xb87f mem
  0xf2800000-0xf280007f irq 9 at device 11.0 on pci2
>Description:
While running ping sweeps of a corporate network the host panics.
Panic does not occur while doing anything else, panic did not occur
2 or 3 months ago running same program under older version of -STABLE.

Problem has been around for at least a few weeks as I pointed to this
problem a while back runinng an earlier -STABLE
 http://docs.freebsd.org/cgi/getmsg.cgi?\
  fetch=109403+0+archive/2002/freebsd-stable/20020915.freebsd-stable

Might be related to http://www.FreeBSD.org/cgi/query-pr.cgi?pr=kern/30952

kgdb says panic occurs at
#6  0xc02a129c in xl_newbuf (sc=0xc1a5c000, c=0xc1a5c194) at /usr/src/sys/pci/if_xl.c:1727
1727            MCLGET(m_new, M_DONTWAIT);
kgdb) print m_new
$3 = (struct mbuf *) 0xc0e6f000
(kgdb) print m_new->m_hdr.mh_flags
$4 = 2
(kgdb) print m_new->m_hdr.mh_type
$5 = 1
(kgdb) print m_new->m_hdr.mh_len
$6 = 98
(kgdb) print m_new->m_hdr.mh_data
$7 = 0xc0e6f02c "" 

In the networking area, the kernel has IPF built-in (for Security),
and loads the kernel module for IPFW and DUMMYNET (for traffic shaping)
(come to think of it, a few months ago DUMMYNET was not being used,
 so I could check if the problem occurs without IPFW and DUMMYNET)
See above listed freebsd-stable posting for dmesg output.
>How-To-Repeat:
The bash script which can reliably generate panics generates
ping requests with an alias source address and a payload string
which includes the destination address.  The ping requests are
sent using individual instances of the ping command, due to the
unique payload.  The script forks about 1000 or 1500 pings, then
waits for them all to complete, then sends another 1000 or so.
After sending about about 1.2 million pings, the panic occurs,
although this could be coincidence, as it will sometimes occur
shortly after a reboot when picking up the scan where it left off
after the panic, but sometimes will continue on without problem.
The panic will always occur before the script completes, it is
repeatable.
>Fix:
      
>Release-Note:
>Audit-Trail:
>Unformatted:

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