A system in the field stopped responding. nicinfo would stay send blocked forever, same for ifconfig.

12297   1 roc/boot/io-pkt-v4  21r SIGWAITINFO      484K   19M  4096(516K)*
   12297   2 roc/boot/io-pkt-v4 100r MUTEX            484K   19M  8192(132K) 
   12297   3 roc/boot/io-pkt-v4 100r RECEIVE          484K   19M  4096(132K) 
   12297   4 roc/boot/io-pkt-v4  21r RECEIVE          484K   19M  4096(132K) 
   12297   5 roc/boot/io-pkt-v4  11r MUTEX            484K   19M  4096(132K) 
   12297   6 roc/boot/io-pkt-v4  21r CONDVAR          484K   19M  4096(132K) 
   12297   7 roc/boot/io-pkt-v4 100r MUTEX            484K   19M  4096(132K) 
   12297   8 roc/boot/io-pkt-v4  11r RECEIVE          484K   19M  4096(132K) 
            libc.so.3          @b0300000             468K   12K
            devnp-e1000.so     @b8200000             180K  4096
            lsm-qnet.so        @b822e000             172K   40K
            /dev/mem           @40100000 (fdd80000)        128K
            /dev/mem           @40120000 (fdde0000)        128K

A 3 seconde trace showed no interrupt at all.  Only thread is active.

Any pointers?