explorer: forked workers have no timeout, no kill-on-drop, and waitpid(-1) reaps unrelated children

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Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
56/100
Issue type
Bug
Clarity
Clearly specified
Activity status
Active
Tech stack
rust
Domain
testing-qa, tooling

Research direction

Start in crates/moonpool-explorer/src/worker.rs:160 and trace the wait_any call sites in controller.rs:313 and controller.rs:417, then inspect Explorer ownership and SharedMemory cleanup in shared_mem.rs:77. Done means Explorer cleanup terminates active workers, polling observes a per-worker wall-clock ceiling, and reaping is limited to pids spawned by the explorer.

Written by the indexing model from the issue text.

Description

bug

Found during the pre-release source audit of 8d9e779 (read-only, nothing compiled or run). Severity: medium. Status: confirmed.

Where

  • crates/moonpool-explorer/src/worker.rs:160 (wait_any: waitpid(-1, &status, 0), no WNOHANG, no deadline)
  • crates/moonpool-explorer/src/controller.rs:313 (final drain loop)
  • crates/moonpool-explorer/src/controller.rs:417 (reap_one_and_process)
  • Explorer has no Drop impl (only SharedMemory does, shared_mem.rs:77)

Failure scenario

A child stuck outside the simulation (a tight loop in user process code, a blocking syscall) is not covered by the in-simulation RunStallGuard; the controller blocks in waitpid until the CI job timeout kills everything with no diagnostic. A controller panic or SIGKILL orphans live children that keep running full simulations while holding the MAP_SHARED assertion and sancov regions. waitpid(-1, ..) also reaps any unrelated child of the host process when moonpool is embedded in a larger harness.

Proposed fix

Add a Drop for Explorer that SIGKILLs every pid in active, poll with WNOHANG against a per-worker wall-clock ceiling, and wait on the specific pids the explorer spawned.

Dominant language
Rust
Stars
49
Forks
3
Avg merge
1h 4m
Merged PRs (30d)
41

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