Messages in this thread | | | Date | Thu, 13 Nov 2008 18:12:20 +0100 | From | Andi Kleen <> | Subject | Re: [PATCH 1/2] tracing/function-return-tracer: Make the function return tracer lockless |
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> > 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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