Fixing race condition at Module::forward method #21398
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Summary: Module::forward method calls find_method() function potentially in multiple threads. Internally it calls find_offset() method and reads dict_ object. If the correspondent name is not in a dictionary thread call insert() method and modifies dict_ object. At the same time when first thread modifies dict_ object another thread can enter forward()->find_method()->find_offset() path and access dict_ object for reading while it have been modified -> crash. Moved mutex protection up to protect both calls find_offset() and insert(). Consider to use C++ 17 shared_mutex locking object instead of recursive_mutex object. Differential Revision: D15638942 fbshipit-source-id: a13be64763ed791b644a601201d34cd124303bc2
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This pull request has been merged in 42b2f56. |
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Summary:
Module::forward method calls find_method() function potentially in multiple threads.
Internally it calls find_offset() method and reads dict_ object.
If the correspondent name is not in a dictionary thread call insert() method and modifies dict_ object.
At the same time when first thread modifies dict_ object another thread can enter forward()->find_method()->find_offset() path
and access dict_ object for reading while it have been modified -> crash.
Moved mutex protection up to protect both calls find_offset() and insert().
Consider to use C++ 17 shared_mutex locking object instead of recursive_mutex object.
Differential Revision: D15638942