Kernel panic in dovecot-ee-lmtp on Debian 8

[Timo Sirainen]

On 25 Apr 2016, at 13:48, Tobi <tobster at brain-force.ch> wrote:
> 
> Hi list
> 
> I just realized that that I don not receive all mails in my mailbox
> (running dovecot-ee 2.2.23.1-1 on Debian 8). On my frontend servers
> (running postfix) the queue fills up with mails that cannot be delivered
> via lmtp to my backend servers. The error message on the frontend is
> "lost connection with backend while sending data"
> When I checked the logs on the backend server I found upon every
> delivery attempt kernel panics
> 
> Apr 25 12:33:36 mbox1 dovecot: lmtp(REDACTED): Panic: epoll_ctl(del, 18)
> failed: Bad file descriptor
> Apr 25 12:33:36 mbox1 dovecot: lmtp(REDACTED): Error: Raw backtrace:

Can you get a core dump and gdb backtrace? See http://dovecot.org/bugreport.html#coredumps

> /usr/lib/dovecot/libdovecot-sieve.so.0(program_client_run+0xe8)
> [0x7faa17d3b308] ->
> /usr/lib/dovecot/modules/sieve/lib90_sieve_extprograms_plugin.so(+0x45b8) [0x7faa15d855b8]
> ->
> /usr/lib/dovecot/libdovecot-sieve.so.0(sieve_interpreter_continue+0x7c)
> [0x7faa17cfa2ac] ->
> 
> the weird thing is that this is not concerning all incoming mails. From
> time to time the frontends can deliver messages to my backends. I just
> tested it with a mail from work. It arrived via a frontend that has
> other mails in queue that could not be delivered so far.
> 
> Does anyone have an idea where I could look for the root cause of this
> panic messages?

Looks like somehow caused by sieve extprograms.