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SubjectRe: [PATCH 1/2] tracing/function-return-tracer: Make the function return tracer lockless
> > local register i
> > i = index;
> > write to index'ed array using i
> > <--------- interrupt here would overwrite data
> > ...
> > index = i + 1;
>
>
> Yes in the common case that would be a danger. But here, if an
> interrupt is raised, it will increment
> the counter and then decrement it at return time without dropping the
> cpu. So after the interrupt, the
> value will remain the same...

The buffer contents will not be necessarily
the same. See the scenario above. The interrupt would use the
same i as the current function and would overwrite the
partially written entry.

-Andi


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