On 05/01/2026 17:14 EET Washington Odhiambo via dovecot <dovecot@dovecot.org> wrote:
On Mon, Jan 5, 2026 at 5:55 PM Aki Tuomi <aki.tuomi@open-xchange.com> wrote:
On 05/01/2026 16:44 EET Washington Odhiambo via dovecot < dovecot@dovecot.org> wrote:
Can someone please give simple steps to make dovecot to coredump on Debian 12? After reading this: https://doc.dovecot.org/2.4.2/developers/debugging.html#coredumps - I am still not able to get it to work. I have been running dovecot from git (yes, I know I shouldn't!) until I updated today and then it would be killed by signal 11.
I have so far installed the release versions and all is fine, but I'd like to ensure that in the future, I have the coredump working.
-- Best regards, Odhiambo WASHINGTON, Nairobi,KE +254 7 3200 0004/+254 7 2274 3223 In an Internet failure case, the #1 suspect is a constant: DNS. "Oh, the cruft.", egrep -v '^$|^.*#' ¯\_(ツ)_/¯ :-) [How to ask smart questions: http://www.catb.org/~esr/faqs/smart-questions.html] Can someone please give simple steps to make dovecot to coredump on Debian 12? After reading this: [1] https://doc.dovecot.org/2.4.2/developers/debugging.html#coredumps
I am still not able to get it to work. I have been running dovecot from git (yes, I know I shouldn't!) until I updated today and then it would be killed by signal 11. I have so far installed the release versions and all is fine, but I'd like to ensure that in the future, I have the coredump working.
I would recommend installing systemd-coredump. Usually the trick with getting coredumps is fs.suid_dumpable=2, and if it's login process, setting
service imap-login { chroot = }
to disable chrooting. systemd-coredump however usually works quite nicely.
Aki
Can you please simplify these steps further?
Do I have to add fs.suid_dumpable=2 to /etc/sysctl.conf and then do sysctl -p? Then what next? I installed systemd-coredump. Then what next? Reading through the details was taking all my time. That's why I opted to install the release versions (manually, actually) then ask for the simplified steps to get the coredumps.
If you can help me with that, then I can recompile the git versions and obtain the coredump.
What was happening was the usual login failure - for both POP3 and IMAP4. Authentication was succeeding but dovecot crashed immediately after and wasn't able to get to the mailbox. I interacted with the daemons from CLI and both just threw me out. 'doveadm log errors' showed they were killed by signal 11, but nothing else much. That's what led me to consider the coredump path.
-- Best regards, Odhiambo WASHINGTON, Nairobi,KE +254 7 3200 0004/+254 7 2274 3223 In an Internet failure case, the #1 suspect is a constant: DNS. "Oh, the cruft.", egrep -v '^$|^.*#' ¯\_(ツ)_/¯ :-) [How to ask smart questions: http://www.catb.org/~esr/faqs/smart-questions.html] On Mon, Jan 5, 2026 at 5:55PM Aki Tuomi <[1]aki.tuomi@open-xchange.com> wrote:
> On 05/01/2026 16:44 EET Washington Odhiambo via dovecot <[2]dovecot@dovecot.org> wrote: > > > Can someone please give simple steps to make dovecot to coredump on Debian > 12? > After reading this: > [3]https://doc.dovecot.org/2.4.2/developers/debugging.html#coredumps - I am > still not able to get it to work. > I have been running dovecot from git (yes, I know I shouldn't!) until I > updated today and then it would be killed by signal 11. > > I have so far installed the release versions and all is fine, but I'd like > to ensure that in the future, I have the coredump working. > > -- > Best regards, > Odhiambo WASHINGTON, > Nairobi,KE > +254 7 3200 0004/+254 7 2274 3223 > In an Internet failure case, the #1 suspect is a constant: DNS. > "Oh, the cruft.", egrep -v '^$|^.*#' -\_(Tu)_/- :-) > [How to ask smart questions: > [4]http://www.catb.org/~esr/faqs/smart-questions.html] > Can someone please give simple steps to make dovecot to coredump on Debian > 12? > After reading > this: [1][5]https://doc.dovecot.org/2.4.2/developers/debugging.html#coredumps > - I am still not able to get it to work. > I have been running dovecot from git (yes, I know I shouldn't!) until I > updated today and then it would be killed by signal 11. > I have so far installed the release versions and all is fine, but I'd like > to ensure that in the future, I have the coredump working. > -- I would recommend installing systemd-coredump. Usually the trick with getting coredumps is fs.suid_dumpable=2, and if it's login process, setting service imap-login { chroot = } to disable chrooting. systemd-coredump however usually works quite nicely. AkiCan you please simplify these steps further? Do I have to add fs.suid_dumpable=2 to /etc/sysctl.conf and then do sysctl -p? Then what next? I installed systemd-coredump. Then what next? Reading through the details was taking all my time. That's why I opted to install the release versions (manually, actually) then ask for the simplified steps to get the coredumps. If you can help me with that, then I can recompile the git versions and obtain the coredump. What was happening was the usual login failure - for both POP3 and IMAP4. Authentication was succeeding but dovecot crashed immediately after and wasn't able to get to the mailbox. I interacted with the daemons from CLI and both just threw me out. 'doveadm log errors' showed they were killed by signal 11, but nothing else much. That's what led me to consider the coredump path.
Best regards, Odhiambo WASHINGTON, Nairobi,KE
Did you check coredumpctl? Also make sure sysctl kernel.core_pattern points to systemd-coredump and you have fs.suid_dumpable=2.
Aki