46 lines
1.3 KiB
Rust
46 lines
1.3 KiB
Rust
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// ignore-windows: Concurrency on Windows is not supported yet.
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use std::thread::spawn;
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use std::ptr::null_mut;
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use std::sync::atomic::{Ordering, AtomicPtr};
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#[derive(Copy, Clone)]
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struct EvilSend<T>(pub T);
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unsafe impl<T> Send for EvilSend<T> {}
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unsafe impl<T> Sync for EvilSend<T> {}
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pub fn main() {
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// Shared atomic pointer
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let pointer = AtomicPtr::new(null_mut::<usize>());
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let ptr = EvilSend(&pointer as *const AtomicPtr<usize>);
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// Note: this is scheduler-dependent
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// the operations need to occur in
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// order, otherwise the allocation is
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// not visible to the other-thread to
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// detect the race:
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// 1. alloc
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// 2. write
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unsafe {
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let j1 = spawn(move || {
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//Concurrent allocate the memory.
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//Uses relaxed semantics to not generate
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//a release sequence.
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let pointer = &*ptr.0;
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pointer.store(Box::into_raw(Box::new(0usize)), Ordering::Relaxed);
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});
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let j2 = spawn(move || {
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let pointer = &*ptr.0;
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*pointer.load(Ordering::Relaxed) = 2; //~ ERROR Data race
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});
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j1.join().unwrap();
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j2.join().unwrap();
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// Clean up memory, will never be executed
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drop(Box::from_raw(pointer.load(Ordering::Relaxed)));
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}
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}
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