Messages in this thread | | | Date | Mon, 30 Jun 2008 11:28:22 -0300 | From | Henrique de Moraes Holschuh <> | Subject | Re: PATCH: 2.6.26-rc8: Fix IRQF_DISABLED for shared interrupts |
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On Mon, 30 Jun 2008, Stefan Becker wrote: > Good question. What happens when you mix a random and a not-so-random > source: does the result have an as good random quality as the original
It becomes unusable. In fact, I find it likely that shared IRQs are not safe for random data gathering at all in general. IRQs are not in fact completely random, they just (sometimes) have a very small ammount of randomness in them. And the combined result you see in a shared IRQ line could be correlated or "get somewhat more correlated" because of the sharing (they go over the same BUS -> one can delay the other, etc)... and that correlation might be dangerous.
IMO, the safe thing to do is to block shared IRQs from being used as random sources.
-- "One disk to rule them all, One disk to find them. One disk to bring them all and in the darkness grind them. In the Land of Redmond where the shadows lie." -- The Silicon Valley Tarot Henrique Holschuh
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