Squid problem: "ipcache_create_dnsserver: fork: (35) Operation would block"

I run Squid 1.0.9 on an Digital Unix (ex-OSF1) 4.0 machine. When I 'kill
-HUP' Squid to reread the configuration file, most of the time (but not
always) I get this:

[11/Sep/1996:10:20:27 +0200] ipcache.c:1053: ipcacheOpenServers:
Starting 5 'dns_server' processes
[11/Sep/1996:10:20:27 +0200] ipcache.c:256: ipcache_create_dnsserver:
 fork: (35) Operation would block
[11/Sep/1996:10:20:27 +0200] ipcache.c:1057: ipcacheOpenServers:
WARNING: Cannot run 'dnsserver' process.
[11/Sep/1996:10:20:27 +0200] ipcache.c:1058: Fallling
back to the blocking version.

I have to 'kill -INT' Squid and restart it to have the DNS servers :-(

More facts:

- Squid exhibit this behaviour since at least version 1.0 (we upgrade
regularly but it doesn't affect the bug),
- I manage another cache on an Alpha with the same version of Digital
Unix and of Squid. It never has the problem (its load is much lower). So
I cannot do extensive tests because the only machine with the symptoms is
an important server which I cannot stop at will,
- the manual page on fork does not list EWOULDBLOCK "Operation would
block" as a possible result (EAGAIN and ENOMEM are the only ones).
Received on Wed Sep 11 1996 - 02:46:00 MDT