Florentin DUBOIS
d412fb10d7
Closes #58651 ## Problem On Linux, long-lived Zed sessions accumulate thousands of open procfs handles (`/proc/<pid>/stat`, `/proc/<pid>/task/<tid>/stat`). A degraded 6-hour session was measured holding **9,675 FDs, 97% of them never-closed procfs stat handles**, alongside system-wide clipboard breakage (Wayland clipboard `send()` stretching from 13 ms to ~17 s, which makes every other client abort the paste). The leak comes from `PtyProcessInfo` in `crates/terminal/src/pty_info.rs`, through three interacting sysinfo 0.37 behaviors: 1. **Hidden full-system snapshot per terminal.** `System::new_with_specifics(RefreshKind::nothing().with_processes(…))` immediately refreshes **all** processes. Each refreshed process gets a `Process` entry that caches an **open `/proc/<pid>/stat` file** for the lifetime of the entry (a documented sysinfo optimization). 2. **Task enumeration is opt-out.** `ProcessRefreshKind::nothing()` keeps `tasks: true`, so that constructor snapshot also creates one entry — and one open `/proc/<pid>/task/<tid>/stat` — **per thread on the machine**, per terminal. 3. **No eviction outside the refreshed set.** The recurring refresh uses `ProcessesToUpdate::Some(&[foreground_pid])`; sysinfo's dead-process sweep only visits pids in that list. Every former foreground process (one per command the user runs) therefore stays in the map forever, pinning its FD. sysinfo silently raises `RLIMIT_NOFILE` and budgets half of it (~262k) for this cache, so the process never hits `EMFILE` — it just degrades. Reproduction (standalone, sysinfo 0.37.2, Fedora 44): constructing one `System` the way `PtyProcessInfo::new` does instantly retains **3,566 FDs**; each simulated shell command leaks one more, unbounded. ## Fix All changes confined to `pty_info.rs`: - `.without_tasks()` on the `ProcessRefreshKind` — eliminates the per-thread handle class entirely. - Replace the constructor's implicit all-process scan with `System::new()` plus a refresh of just the spawned child, so `kill_child_process()` still works before the first foreground refresh. - Rebuild the `System` whenever the foreground pid changes, and refresh `[foreground, child]` so the dead-process sweep can actually evict stale entries. The map is now bounded at 2 entries per terminal. With the fix, the same repro stays flat at ~6 FDs across arbitrary command churn, and the foreground process info (name/cwd/argv for tab titles) keeps working. The regression test fails on `main` (3,747 retained entries on a desktop system) and passes with the fix (≤ 2). Note: the ~17 s clipboard `send()` on the degraded session is a coupled symptom; the FD/process-map bloat is the verified defect fixed here. The Wayland data-source lifecycle is tracked separately in #58446. Release Notes: - Fixed a file descriptor leak in terminal process tracking that degraded long-running sessions on Linux, including system-wide clipboard breakage ([#58651](https://github.com/zed-industries/zed/issues/58651)). Signed-off-by: Florentin Dubois <florentin.dubois@clever.cloud>
Zed
Welcome to Zed, a high-performance, multiplayer code editor from the creators of Atom and Tree-sitter.
Installation
On macOS, Linux, and Windows you can download Zed directly or install Zed via your local package manager (macOS/Linux/Windows).
Other platforms are not yet available:
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Developing Zed
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See CONTRIBUTING.md for ways you can contribute to Zed.
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Licensing
Zed source code is licensed primarily under GPL-3.0-or-later, with Apache-2.0 components where marked.
License information for third party dependencies must be correctly provided for CI to pass.
We use cargo-about to automatically comply with open source licenses. If CI is failing, check the following:
- Is it showing a
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Sponsorship
Zed is developed by Zed Industries, Inc., a for-profit company.
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- me: do a nixos integration test (using KVM)
- agent: i need to turn off the sandbox
- me: "allow for this thread"
- agent: runs the tests unsandboxed
- me: use the terminal to ls this directory
- agent: runs
lssandboxed