fn probe_lock() -> &'static Mutex<()>Expand description
Process-wide lock serializing every probe() call. std::panic::set_hook
/ take_hook are global, process-wide state, not thread-local - without
this, two probe() calls running on different threads at once (e.g.
cargo test’s default parallel test execution) can install/restore each
other’s hooks out of order and corrupt the captured panic location. The
bisection driver in bisect.rs only ever calls probe() sequentially on
one thread anyway, so this lock is uncontended in normal use; it exists
purely to make probe() itself safe to call concurrently.