kern/87094: 5.4 system with SMP and IPFW crashes under load (mbuf underrun)

[Chris Ulrich]

>Number:         87094
>Category:       kern
>Synopsis:       5.4 system with SMP and IPFW crashes under load (mbuf underrun)
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Fri Oct 07 21:20:08 GMT 2005
>Closed-Date:
>Last-Modified:
>Originator:     Chris Ulrich
>Release:        5.4-RELEASE-p7 / intel 386
>Organization:
University of California at Riverside
>Environment:
FreeBSD wg03 5.4-RELEASE-p7 FreeBSD 5.4-RELEASE-p7 #0: Tue Oct  4 15:57:24 PDT 2005     shock at wg04:/usr/obj/usr/src/sys/FW_NO_SMP  i386

>Description:
Firewall system running nat pumping packets between 2 intel EM interfaces.

When the system is running IPFW and has SMP turned on, the system will crash after a random (large) number of packets flow through the system.
>How-To-Repeat:
Run SMP and IPFW and natd on a 5.4 i386 system and run iperf between one interface and the other (server outside the nat interface).

After a minute or so, netstat -m will show something like:
4294266316 mbufs in use
4294737989/25600 mbuf clusters in use (current/max)
3560445 KBytes allocated to network
201 calls to protocol drain routines

After another period of time, the system will eventually reboot.  The behavior is not related to load or firewall rule changes.

>Fix:
              
>Release-Note:
>Audit-Trail:
>Unformatted: