untracked child process (PID XXXXX) exited with exit code 120

My guess would be that the postmaster in your container is running with
PID=1.
The unexpected process was probably started by docker entrypoint before it
did exec postgres [...].
As a result, this subprocess became a direct child of the postmaster and we
got the problem.

The most common solution is to avoid running postmaster with PID=1.
There are two options available:
1. dumb-init
2. start container using "docker run --init [...]"

On Thu, 7 May 2026 at 19:37, Torsten Krah <krah.tm@gmail.com> wrote:

Hi,

I am running PostgreSQL 18.3 (Debian 18.3-1.pgdg13+1) (docker image)
and found this in my database logs the other day:

2026-05-07 18:39:13.947 CEST [1] LOG: untracked child process (PID 33254)
exited with exit code 120
2026-05-07 18:39:13.947 CEST [1] LOG: terminating any other active server
processes
2026-05-07 18:39:14.077 CEST [1] LOG: all server processes terminated;
reinitializing

Anyone an idea about that untracked child process and what exit code
120 of that process would mean / want to tell me?

Thanks.

Torsten

PS: I used https://www.postgresql.org/search/ , but was unsuccessful so
far to get any hints on this, but maybe I just did not find the correct
question yet ;).

--
Regards,
--
Alexander Kukushkin

Am Donnerstag, dem 07.05.2026 um 19:51 +0200 schrieb Alexander
Kukushkin:

My guess would be that the postmaster in your container is running
with
PID=1.
The unexpected process was probably started by docker entrypoint
before it
did exec postgres [...].
As a result, this subprocess became a direct child of the postmaster
and we
got the problem.

The most common solution is to avoid running postmaster with PID=1.
There are two options available:
1. dumb-init
2. start container using "docker run --init [...]"

My /docker-entrypoint-initdb.d is empty and I did not customize the
default entrypoint or command to run (there was a ready to use data dir
/ volume, so it just skipped initialization on start), so I am not sure
what else should have been started, but I know, just guesswork here.

Between starting the pod initially:

16:52:28.317

and the time the untracked process did fail:

18:39:13.947

nearly 2 hours passed, ah too bad I will never know what PID 120 was.

Yes, the postgres image postgres:18-trixie does run the postgres
process with PID=1:

postgres 1 0.0 0.2 4443124 139360 ? Ss May06 0:27 postgres

Using kubernetes as runtime, there is no "--init" option and e.g. tini
is not in the image - if is is a problem running postgres with pid=1,
could e.g. tini be added to the image (if so, do you know where to
address this?) and used as default entrypoint (I know I can build one
myself and extend that image to provide tini, but I would prefer just
to use the upstream image as-is)?

kind regards

Torsten

Torsten Krah <krah.tm@gmail.com> writes:

Yes, the postgres image postgres:18-trixie does run the postgres
process with PID=1:

That's just insane. You should file a bug with whoever supplies
that image.

regards, tom lane

https://github.com/docker-library/postgres/issues/1349

Someone already did, unfortunately they denied that request ... it seems I
have to build my own image or use another one.

Thanks anyway, I can work with that and fix it.

kind regards

Torsten