Overview of upstream stability issues

[roberth]

Open issues

• fetchGit transient failure not retried, Empty reply from server NixOS/nix#9153

Worrying but apparently unaffected

Nix substitution may hang:

• nix copy hangs forever sometimes NixOS/nix#3017 (worrying but unaffected?)

---

Upstreamed fixes

... currently no fixes awaiting release ...

Released fixes

Fixed in GHC 9.4pre, GHC 9.2.2 (needs agent release)

• -compact-unwind interferes with C++ exceptions on darwin

Fixed in Nix 2.12

non-existent output, NixOS/nix 2.12, recent nixpkgs.nix, hercules-ci-agent master

• nix-build: requires non-existent output 'out' from input derivation NixOS/nix#6572

NixOS nix-daemon socket not always available

• nixos/nix-daemon: Ensure continued availability of daemon socket NixOS/nixpkgs#161059 (nixos-unstable)
• [Backport release-21.11] nixos/nix-daemon: Ensure continued availability of daemon socket NixOS/nixpkgs#163323 (nixos-21.11)

Fixed in Nix 2.7.0 (agent 0.8.7):

nix-daemon deadlocks, especially on darwin:

• Fix deadlocked nix-daemon zombies on darwin #3294 NixOS/nix#6052

Fixed in Nix 2.6.0 (agent 0.8.6):

Crashes (worker exited with -11 or -6)

• Fix segfault or stack overflow caused by large derivation fields NixOS/nix#5875
• Force all Pos* to be non-null NixOS/nix#5192

Fixed in Nix 2.4 (agent 0.8.5):

Crashes (worker exited with -11)

• Fix memory corruption caused by GC-invisible coroutine stacks NixOS/nix#4206
• Fix gc crash NixOS/nix#4944

Deadlocks

• Fix RemoteStore pool deadlock in filterSource etc NixOS/nix#4207

Infinite loops

• Fix substitution loop #3964, #3534 NixOS/nix#4158

Cache invalidation

• pathInfoCache: Respect disk cache TTLs #3398 NixOS/nix#3403

Significant fixes by upstream

Linux 6.1 - 6.2 mmap crashes

• OOM events right after start mmap 4096 bytes at (nil): Cannot allocate memory #514

[roberth]

Will open individual issues from now on.