[Bug libstdc++/62313] Data race in debug iterators

[dvyukov at google dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62313
--- Comment #6 from Dmitry Vyukov <dvyukov at google dot com> ---
> The tests for the debug mode don't generally involve threads, so that isn't 
> likely to help.

Then you can run any heavily multithreaded program that extensively uses stl
and is currently race-free. That last condition is somewhat tricky. I could
suggest running Chromium browser as we oversee it for data races
(http://dev.chromium.org/developers/testing/threadsanitizer-tsan-v2), but it
can be somewhat tricky.

====

The issue introduces a data race into the following program -- 'it' parameter
is constructed concurrently with list mutation. If it is a bug in user program,
them all concurrent C++ program that use stl are buggy.

class X {
    std::list<int> li_;
    std::mutex mu_;
public:
    void erase(std::list<int>::iterator it) {
        mu_.lock();
        li_.erase(it);
        mu_unlock();
    }
};