Skip to content

clear_after_fork #6933

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
youknowone merged 1 commit into from
Feb 1, 2026
Merged

clear_after_fork #6933

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
16 changes: 16 additions & 0 deletions crates/vm/src/object/core.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -197,6 +197,15 @@ mod weakref_lock {
core::hint::spin_loop();
}
}

/// Reset all weakref stripe locks after fork in child process.
/// Locks held by parent threads would cause infinite spin in the child.
#[cfg(unix)]
pub(crate) fn reset_all_after_fork() {
for lock in &LOCKS {
lock.store(0, Ordering::Release);
}
}
}

#[cfg(not(feature = "threading"))]
Expand All @@ -212,6 +221,13 @@ mod weakref_lock {
}
}

/// Reset weakref stripe locks after fork. Must be called before any
/// Python code runs in the child process.
#[cfg(all(unix, feature = "threading"))]
pub(crate) fn reset_weakref_locks_after_fork() {
weakref_lock::reset_all_after_fork();
}

// === WeakRefList: inline on every object (tp_weaklist) ===

pub(super) struct WeakRefList {
Expand Down
10 changes: 10 additions & 0 deletions crates/vm/src/signal.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -50,6 +50,16 @@ pub(crate) fn set_triggered() {
ANY_TRIGGERED.store(true, Ordering::Release);
}

/// Reset all signal trigger state after fork in child process.
/// Stale triggers from the parent must not fire in the child.
#[cfg(unix)]
pub(crate) fn clear_after_fork() {
ANY_TRIGGERED.store(false, Ordering::Release);
for trigger in &TRIGGERS {
trigger.store(false, Ordering::Relaxed);
}
}

pub fn assert_in_range(signum: i32, vm: &VirtualMachine) -> PyResult<()> {
if (1..NSIG as i32).contains(&signum) {
Ok(())
Expand Down
10 changes: 9 additions & 1 deletion crates/vm/src/stdlib/posix.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -660,8 +660,16 @@ pub mod module {
}

fn py_os_after_fork_child(vm: &VirtualMachine) {
// Reset low-level state before any Python code runs in the child.
// Signal triggers from the parent must not fire in the child.
crate::signal::clear_after_fork();
crate::stdlib::signal::_signal::clear_wakeup_fd_after_fork();

// Reset weakref stripe locks that may have been held during fork.
#[cfg(feature = "threading")]
crate::object::reset_weakref_locks_after_fork();

// Mark all other threads as done before running Python callbacks
// See _PyThread_AfterFork behavior
#[cfg(feature = "threading")]
crate::stdlib::thread::after_fork_child(vm);

Expand Down
7 changes: 7 additions & 0 deletions crates/vm/src/stdlib/signal.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -679,6 +679,13 @@ pub(crate) mod _signal {
}
}

/// Reset wakeup fd after fork in child process.
/// The child must not write to the parent's wakeup fd.
#[cfg(unix)]
pub(crate) fn clear_wakeup_fd_after_fork() {
WAKEUP.store(INVALID_WAKEUP, Ordering::Relaxed);
}

pub(crate) fn module_exec(
vm: &VirtualMachine,
module: &Py<crate::builtins::PyModule>,
Expand Down
Loading