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Kill shell tool process groups on timeout (#5258)

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## Summary
- launch shell tool processes in their own process group so Codex owns
the full tree
- on timeout or ctrl-c, send SIGKILL to the process group before
terminating the tracked child
- document that the default shell/unified_exec timeout remains 1000 ms

## Original Bug
Long-lived shell tool commands hang indefinitely because the timeout
handler only terminated the direct child process; any grandchildren it
spawned kept running and held the PTY open, preventing Codex from
regaining control.

## Repro Original Bug
Install next.js and run `next dev` (which is a long-running shell
process with children). On openai:main, it will cause the agent to
permanently get stuck here until human intervention. On this branch,
this command will be terminated successfully after timeout_ms which will
unblock the agent. This is a critical fix for unmonitored / lightly
monitored agents that don't have immediate human observation to unblock
them.

---------

Co-authored-by: Michael Bolin <mbolin@openai.com>
Co-authored-by: Michael Bolin <bolinfest@gmail.com>
This commit is contained in:
Luca King
2025-11-07 19:54:35 -06:00
committed by GitHub
parent 91b16b8682
commit a2fdfce02a
2 changed files with 101 additions and 12 deletions
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32
codex-rs/core/src/spawn.rs
View File

@@ -64,24 +64,32 @@ pub(crate) async fn spawn_child_async(
// any child processes that were spawned as part of a `"shell"` tool call
// to also be terminated.
// This relies on prctl(2), so it only works on Linux.
#[cfg(target_os = "linux")]
#[cfg(unix)]
unsafe {
#[cfg(target_os = "linux")]
let parent_pid = libc::getpid();
cmd.pre_exec(move || {
// This prctl call effectively requests, "deliver SIGTERM when my
// current parent dies."
if libc::prctl(libc::PR_SET_PDEATHSIG, libc::SIGTERM) == -1 {
if libc::setpgid(0, 0) == -1 {
return Err(std::io::Error::last_os_error());
}
// Though if there was a race condition and this pre_exec() block is
// run _after_ the parent (i.e., the Codex process) has already
// exited, then parent will be the closest configured "subreaper"
// ancestor process, or PID 1 (init). If the Codex process has exited
// already, so should the child process.
if libc::getppid() != parent_pid {
libc::raise(libc::SIGTERM);
// This relies on prctl(2), so it only works on Linux.
#[cfg(target_os = "linux")]
{
// This prctl call effectively requests, "deliver SIGTERM when my
// current parent dies."
if libc::prctl(libc::PR_SET_PDEATHSIG, libc::SIGTERM) == -1 {
return Err(std::io::Error::last_os_error());
}
// Though if there was a race condition and this pre_exec() block is
// run _after_ the parent (i.e., the Codex process) has already
// exited, then parent will be the closest configured "subreaper"
// ancestor process, or PID 1 (init). If the Codex process has exited
// already, so should the child process.
if libc::getppid() != parent_pid {
libc::raise(libc::SIGTERM);
}
}
Ok(())
});