Re: [PATCH] drivers/net: remove network drivers' last few uses ofIRQF_SAMPLE_RANDOM

From: Jeff Garzik
Date: Thu May 15 2008 - 18:42:27 EST


Brandeburg, Jesse wrote:
we've been hearing rumblings of big customers wanting (maybe requiring)
wired network drivers from Intel to advertise this flag. Jeff have you
heard of such?

I think the argument is that a headless system (no keyboard/mouse, no
soundcard, probably no video) with a libata based driver and a network
driver without IRQF_SAMPLE_RANDOM has *no* sources of entropy. In this
case the argument is very strong for at least *some* source of entropy
from interrupts so that randomness can get some external input. Just
try rebuilding a kernel RPM over an ssh session and you'll see what I
mean.

In short, I agree with Alan's IRQF_SAMPLE_DUBIOUS, and know of Linux
customers who also want the same.


So I guess a good message for customers might be:

Don't depend on an entropy source whose volume decreases as workload and network traffic increase.

Jeff


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