ssh client sometimes hangs

$ lsb_release -rd
Description: Ubuntu 8.10
Release: 8.10
$ apt-cache policy openssh-client
openssh-client:
  Installed: 1:5.1p1-3ubuntu1
  Candidate: 1:5.1p1-3ubuntu1
  Version table:
 *** 1:5.1p1-3ubuntu1 0
        500 http://us.archive.ubuntu.com intrepid/main Packages
        100 /var/lib/dpkg/status

I have .ssh key files that I generated years ago. I copied them to ~/.ssh on my ubuntu system. Most of the time when I use ssh to run a command on another system it works fine. Once in 50 times ssh hangs locally.

This is not a network problem ... same issue happens with "localhost". E.g. if I run:

$ while :
> do ssh localhost date
> done

It will print the date a few dozen times, then the loop hangs (^C interrupts it).

I tried using strace to see what was happening. The ssh process was hung reading from a socket.
Looking back through the strace, the socket was connected to some local keyring thing.
Here are some relevent lines from strace output:

socket(PF_FILE, SOCK_STREAM, 0) = 4
fcntl(4, F_SETFD, FD_CLOEXEC) = 0
connect(4, {sa_family=AF_FILE, path="/tmp/keyring-fed2nU/ssh"}, 110) = 0
write(4, "\0\0\0\1", 4) = 4
write(4, "\v", 1) = 1
read(4, "\0\0\2h", 4) = 4
read(4, "\f\0\0\0\2\0\0\0\225\0\0\0\7ssh-rsa\0\0\0\1#\0\0\0\201"..., 616) = 616
write(3, "$K \250\310\200\247\266-\25\257\212f\226h\234\f\275a\310"..., 64) = 64
select(4, [3], NULL, NULL, NULL) = 1 (in [3])
read(3, "\34t\351\267\262/\362\315\33\r\3019\301\361dX\264\276\377"..., 8192) = 80
futex(0x7f956651f2e0, 0x81 /* FUTEX_??? */, 2147483647) = 0
futex(0x7f956651f160, 0x81 /* FUTEX_??? */, 2147483647) = 0
futex(0x7f9567385450, 0x81 /* FUTEX_??? */, 2147483647) = 0
futex(0x7f9567159590, 0x81 /* FUTEX_??? */, 2147483647) = 0
futex(0x7f95671599d0, 0x81 /* FUTEX_??? */, 2147483647) = 0

....

open("/dev/urandom", O_RDONLY) = 5
fstat(5, {st_mode=S_IFCHR|0666, st_rdev=makedev(1, 9), ...}) = 0
read(5, "\21\207y;\216\357\361\37\310\230\300\211GYpr\236a\235\t"..., 20) = 20
close(5) = 0
write(3, "\314\331H\3711\274\25\v@\201\201vG\rO\230\273d\277&8X2"..., 240) = 240
select(4, [3], NULL, NULL, NULL) = 1 (in [3])
read(3, "\234?r\352\30(\373T\277!bm\224W\30P\247\270\313\234\341"..., 8192) = 192
brk(0x7f95690d9000) = 0x7f95690d9000
brk(0x7f95690d8000) = 0x7f95690d8000
write(4, "\0\0\1\207", 4) = 4
write(4, "\r\0\0\0\225\0\0\0\7ssh-rsa\0\0\0\1#\0\0\0\201\0\300\r"..., 391) = 391
read(4, 0x7fff703fa880, 4) = ? ERESTARTSYS (To be restarted)
--- SIGINT (Interrupt) @ 0 (0) ---
+++ killed by SIGINT +++

A hung ssh process is often revived when some other outging ssh request
is initiated. Quite often the snoozy process wakes up and runs normally.
But sometimes it wakes up and reports a failed connection.