possible race condition (fetch-pack: unexpected disconnect while reading sideband packet)

Hello,

I'd like to report a bug, if it's not already known, but I wasn't able to find it on https://lore.kernel.org/git/.

Setup: We use Git for Windows in version 2.31.0 on MS Windows Server 2019, to access repository on Gitlab 13.10. Both machines are virtual under different physical machines, but still in the same server room connected with high speed network to each other.

Reproducibility: random (like 50:50)

Reproducer: Try to clone (initial clone, or initial init && fetch, doesn't matter) a repo from the gitlab to the machine

Expected results: Repository cloned/fetched successfully

Actual result (when failed): Cloning into 'local-repo-name'... remote: Enumerating objects: 237, done. remote: Counting objects: 100% (237/237), done. remote: Compressing objects: 100% (129/129), done. fetch-pack: unexpected disconnect while reading sideband packet fatal: early EOF fatal: fetch-pack: invalid index-pack output

Notes: Some repositories are almost always successful (doesn't matter if they are bigger or smaller), clone and init+fetch seem to behave similarly (from the perspective of the issue). From any machine on the same network, but e.g. through several network routers or VPN, the issue was never observed. Our current git config: C:\Users\username>git config --list diff.astextplain.textconv=astextplain filter.lfs.clean=git-lfs clean -- %f filter.lfs.smudge=git-lfs smudge -- %f filter.lfs.process=git-lfs filter-process filter.lfs.required=true http.sslbackend=schannel core.autocrlf=true core.fscache=true core.symlinks=false core.editor=notepad pull.rebase=false credential.helper=manager-core credential.https://dev.azure.com.usehttppath=true init.defaultbranch=master http.postbuffer=512000000* core.compression=9* core.packedgitlimit=512m* core.packedgitwindowsize=512m* pack.deltacachesize=2047m* pack.packsizelimit=2047m* pack.windowmemory=2047m* sendpack.sideband=false*

These marked with asterisk(*) were added to localize this issue, without any observable effect.

I'm willing to provide more information or even contribute on the fix, just let me know what should I do/try. Thank you.

Best Regards, Martin Simon