sys/event: fix race in event_wait_multi() #21092
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We need to clear `event->next` while IRQs are still disabled to avoid another thread from calling `event_cancel()` just in-between.
maribu
added
Type: bug
benpicco
approved these changes
Dec 16, 2024
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Contribution description
We need to clear
event->nextwhile IRQs are still disabled to avoid another thread from callingevent_cancel()just in-between.Testing procedure
This will be almost impossible to trigger, as the timing window to trigger than race is pretty narrow.
But the code change is rather trivial and functional regressions will be detected by the CI.
So we have to resort to reasoning about the code here.
Issues/PRs references
None