MemoryStore: prevent race condition #49542
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It looks like rails#46305 accidentally removed the synchronize block that would prevent a race conidition where two threads would read the same value and only a single increment/decrement would take effect as they would both write the same value.
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…tion MemoryStore: prevent race condition
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Thanks, backported to 7-1-stable as well: 52c4aef |
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Motivation / Background
It looks like #46305 accidentally removed the synchronize block that would prevent a race conidition where two threads would read the same value and only a single increment/decrement would take effect as they would both write the same value.
Detail
This was discussed in this PR where the original fix for the expiry was being backported to 7.0
Additional information
Doesn't look like it's easy to deterministically test this. All I could do was to spin multiple threads and sometimes see inconsistencies, but not always
That comment shows how I played with it locally to exacerbates the behavior with
sleepcalls: #49503 (comment)Since 7.1 was just released, do we need a different PR to backport this to 7-1-stable?
Checklist
Before submitting the PR make sure the following are checked:
[Fix #issue-number]