From: Ben Knoble <ben.knoble@gmail.com>
Date: Fri, 22 May 2026 17:46:06 GMT
Subject: Re: I discovered a minor issue with `git fetch`.
Message-ID: <65A1122B-D57C-4789-8C2A-E6330B6992AF@gmail.com>
In-Reply-To: <CAD6AYr9YmcnkdW=Nx=HUKcuaNbv1ukrAbXRnKyGibCQDy8N3hQ@mail.gmail.com>


> Le 22 mai 2026 à 03:48, SURA <surak8806@gmail.com> a écrit :
> 
> Hello everyone
> 
> The child processes spawned by `git fetch` can become zombie processes.
> In most scenarios, these zombie processes are reaped by Process 1, so
> this typically doesn't cause any problems.
> 
> However, within a Docker container, the application service itself is
> sometimes designated as Process 1 (for instance, a service written in
> Go). Since these application services lack the capability to reap
> zombie processes, the zombies will gradually exhaust the available PID
> resources.

See also lore.kernel.org/git/202602231615147.3294516-1-cshung@gmail.com and subsequent discussion for related material.

> 
> Here are the simple steps to reproduce this issue:
> 1. `git clone https://github.com/SURA907/pid-1.git`
> 2. `cd pid-1`
> 3. `docker build -t pid-1 .`
> 4. `docker run -d --name pid-1 pid-1:latest`
> 5. `docker exec -it pid-1 /bin/bash`
> 6. `mkdir repo && cd repo && git init --bare`
> 7. `ps -ef`
> ------
> UID PID PPID C STIME TTY TIME CMD
> root 1 0 0 07:16 ? 00:00:00 tail -f /dev/null
> root 7 0 0 07:16 pts/0 00:00:00 /bin/bash
> root 13 0 0 07:16 pts/1 00:00:00 /bin/bash
> root 29 7 0 07:17 pts/0 00:00:00 ps -ef
> ------
> 
> 8. `git fetch https://github.com/git/git.git`
> 9. `ps -ef` (Run this command from a separate terminal session
> connected to the container)
> ------
> UID PID PPID C STIME TTY TIME CMD
> root 1 0 0 07:16 ? 00:00:00 tail -f /dev/null
> root 7 0 0 07:16 pts/0 00:00:00 /bin/bash
> root 13 0 0 07:16 pts/1 00:00:00 /bin/bash
> root 30 13 1 07:17 pts/1 00:00:00 git fetch https://github.com/git/git.git
> root 31 30 0 07:17 pts/1 00:00:00 /usr/local/libexec/git-core/git
> remote-https https://github.com/git/git.git
> https://github.com/git/git.git
> root 32 31 2 07:17 pts/1 00:00:00
> /usr/local/libexec/git-core/git-remote-https
> https://github.com/git/git.git https://github.com/git/git.git
> root 36 30 30 07:17 pts/1 00:00:00 /usr/local/libexec/git-core/git
> index-pack --stdin -v --fix-thin --keep=fetch-pack 30 on sura-pc
> --pack_header=2,399455
> root 38 7 0 07:17 pts/0 00:00:00 ps -ef
> ------
> 
> 10. ps -ef (after fetch ends)
> ------
> UID PID PPID C STIME TTY TIME CMD
> root 1 0 0 07:16 ? 00:00:00 tail -f /dev/null
> root 7 0 0 07:16 pts/0 00:00:00 /bin/bash
> root 13 0 0 07:16 pts/1 00:00:00 /bin/bash
> root 52 1 0 07:19 ? 00:00:00 [git] <defunct>
> root 53 7 0 07:19 pts/0 00:00:00 ps -ef
> ------
> 
> A zombie process has appeared. It appears to originate from a `fetch`
> subprocess that terminates very quickly; despite several attempts, I
> have been unable to successfully capture it.
> 
> This issue was discovered within a legacy service. A few days after
> upgrading to Git 2.53.0, the system's PID resources were exhausted by
> zombie processes. This is likely the result of recent changes, as this
> problem did not exist in earlier versions (2.4x).
> 
> To be honest, this is not an urgent matter; I have already deployed
> `tini` as the init process (PID 1) to prevent the service from
> becoming unavailable.
>