Hanging imapd-process

[Patrick Scharrenberg]

Hi!

I've got some troubles with my cyrus imapd.
I'm running version 2.1.18-1 on a debian sarge system.

First all works fine and in opposite to uwimapd I had before it is
*really* fast.

But after a while there are some folders I can't write to any more.
Imapd gives the following error message:

  cyrus/imapd[15009]: IOERROR: locking header for user.<mailboxname>:
Interrupted system call

A "lsof | grep <mailboxname>" shows me that there is one imapd (with pid
12138) still accessing this folder, also when there's no open client.
As you can see from my processtable 12xxx is an old process. All other
imapd-processes have much higher pids.

  643 ?        Ss     0:01 /usr/sbin/cyrmaster -d
  658 ?        S      0:00  \_ notifyd
12138 ?        S      0:00  \_ imapd -s -U 30
16491 ?        S      0:00  \_ imapd -s -U 30
16492 ?        S      0:00  \_ imapd -s -U 30
16493 ?        S      0:00  \_ imapd -s -U 30
[...]

A "netstat -an" on the server-side shows that there is still one
established connection.
On the client-side there's not.

I have to say that the imap-serve is behind a netfilter-firewall in a
private-adress-network.
I'm using DNAT to forward port 993 to the imap-server.
On the firewall the "hanging" connection is not shown.

So, whats going wrong here?
When I kill this pid all is fine again.

I'm using Thunderbird v1.0.x, v1.5 and Squirrelmail as client.


Patrick