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Fix deque steal race condition #726
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I'm wondering why this can cause troubles?
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The details are in the discussion here, but it seems that it's not public currently. @taiki-e is it possible to make the discussion visible? I could also copy here the explanation that I wrote there.
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Thanks for the reply! I see it says that a task may be popped twice. But I still does not understand why this is the case given the CAS below https://github.com/crossbeam-rs/crossbeam/pull/726/files#diff-43da9e89d19dacafed5e7cc0d1ac11867f059a529d82daa4fdf2c5e39243a849R640-R644.
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Sorry, I don't know how to make the discussion in the GitHub advisory public.
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Thanks @taiki-e, so I'm just quoting here:
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Even the buffer may changed during this gap, old buffer and new buffer should have the the same value at position
f
. Em.. do we encounter a concrete case?There was a problem hiding this comment.
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Yes, I was able to consistently recreate memory corruption with the old version of the code. Below is a more detailed explanation:
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I will read this tomorrow. Thank you very much for this.