dovecot - Jul 2009 - Fatal: listen(143) failed: Interrupted system call

Hello,
we found dovecot down on one of our servers, with this error in the log:

dovecot: 2009-07-14 04:05:04 Warning: SIGHUP received - reloading
configuration
dovecot: 2009-07-14 04:05:04 Error: Temporary failure in creating login
processes, slowing down for now
dovecot: 2009-07-14 04:05:04 Fatal: listen(143) failed: Interrupted
system call

we can reproduce this error with this tight loop:

while date ; do kill -HUP $(cat /var/run/dovecot/master.pid) ; sleep 15s
; done

after a while dovecot dies with the above error message.

We are using

# dovecot --version
1.0.15

in particular, Debian package with version "1:1.0.15-2.3" .

This started since yesterday, when we upgraded to the latest Debian
Lenny point release.

The situation is rather problematic, and we'd like to here from you if
there something we can do to fix it; if there's something you'd like us
to do, just ask :)

Thanks in advance,
Sandro

On Tue, 2009-07-14 at 14:52 +0200, Sandro Tosi wrote:
> dovecot: 2009-07-14 04:05:04 Warning: SIGHUP received - reloading
> configuration
> dovecot: 2009-07-14 04:05:04 Error: Temporary failure in creating login
> processes, slowing down for now
Does it say elsewhere why this temporary failure happened?
> dovecot: 2009-07-14 04:05:04 Fatal: listen(143) failed: Interrupted
> system call
> 
> we can reproduce this error with this tight loop:
> 
> while date ; do kill -HUP $(cat /var/run/dovecot/master.pid) ; sleep 15s
> ; done
Yeah. listen() can be made to fail by sending a signal at the same time
it's running. But if a signal is sent only once every 15 seconds, that's
a bit strange.. If you run

strace -tt -p `pidof dovecot`

what does it say between the last two HUPs before failing?
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