freebsd 7.0-RELEASE BUG ping: sendto: No buffer space available

[Yony Yossef]

Hi All,
 
I'm facing a temporary network hang on my interfaces following a flood
ping/stress udp test.
 
I'm running a netperf UDP test which is giving results but does not return
to the shell.
client output:
 
UDP UNIDIRECTIONAL SEND TEST from fe80::202:c9ff:fe02:e1fe%mtnic0
(fe80::202:c9ff:fe02:e1fe) port 0 AF_INET6 to fe80::202:c9ff:fe02:e1f4%mt 
nic0 (fe80::202:c9ff:fe02:e1f4) port 0 AF_INET6 
Socket  Message  Elapsed      Messages 
Size    Size     Time         Okay Errors   Throughput 
bytes   bytes    secs            #      #   10^6bits/sec 

 32768    1472   10.02      547428 1694280     643.60 
 32768           10.02       25089             29.50 

 
(HANG)
 
After a minute or two it returns to the shell with the following message:
shutdown_control: no response received  errno 55
 
20 minutes later (!!) the interface is working again.
 
netstat -m and vmstat -z outputs during the hang time:
 
# netstat -m
25687/6578/32265 mbufs in use (current/cache/total)
17404/2438/19842/65536 mbuf clusters in use (current/cache/total/max)
0/1024 mbuf+clusters out of packet secondary zone in use (current/cache)
2071/1369/3440/65536 4k (page size) jumbo clusters in use
(current/cache/total/max)
0/0/0/65536 9k jumbo clusters in use (current/cache/total/max)
0/0/0/3200 16k jumbo clusters in use (current/cache/total/max)
49513K/11996K/61510K bytes allocated to network (current/cache/total)
0/0/0 requests for mbufs denied (mbufs/clusters/mbuf+clusters)
0/0/0 requests for jumbo clusters denied (4k/9k/16k)
0/0/0 sfbufs in use (current/peak/max)
0 requests for sfbufs denied
0 requests for sfbufs delayed
0 requests for I/O initiated by sendfile
0 calls to protocol drain routines
You have new mail in /var/mail/root
 
# vmstat -z | grep mbuf
ITEM                     SIZE     LIMIT      USED      FREE  REQUESTS
FAILURES
mbuf_packet:              256,        0,        0,     1024,     1497,
0
mbuf:                     256,        0,    25687,     5554, 21208920,
0
mbuf_cluster:            2048,    65536,    18428,     1414,   149349,
0
mbuf_jumbo_pagesize:     4096,    65536,     2071,     1369, 17050312,
0
mbuf_jumbo_9k:           9216,    65536,        0,        0,        0,
0
mbuf_jumbo_16k:         16384,     3200,        0,        0,        0,
0
mbuf_ext_refcnt:            4,        0,        0,        0,        0,
0
 
# uname -a
FreeBSD sw260.lab.mtl.com 7.0-RELEASE FreeBSD 7.0-RELEASE #0: Mon Dec 29
11:00:24 UTC 2008
root at sw259.lab.mtl.com:/usr/obj/usr/src.dbg/sys/GENERIC.KDB  amd64
 
The fact that the interface is coming back to life without any driver
activity indicates an OS bug.
 
Thanks,
Yony