Date: Fri, 8 Jan 1999 09:40:15 -0800 From: Steve Watt <steve@Watt.COM> To: Chris Dillon <cdillon@wolves.k12.mo.us> Cc: Mark Murray <mark@grondar.za>, freebsd-stable@FreeBSD.ORG Subject: Re: IRQ entropy causes panics? Message-ID: <19990108094015.A10590@wattres.Watt.COM> In-Reply-To: <Pine.BSF.4.05.9901081108360.1099-100000@duey.wolves.k12.mo.us>; from Chris Dillon on Fri, Jan 08, 1999 at 11:10:52AM -0600 References: <199901081159.NAA17887@greenpeace.grondar.za> <Pine.BSF.4.05.9901081108360.1099-100000@duey.wolves.k12.mo.us>
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On Fri, Jan 08, 1999 at 11:10:52AM -0600, Chris Dillon wrote: > On Fri, 8 Jan 1999, Mark Murray wrote: > > > Steve Watt wrote: > > > [ serial irq running 800int/sec ] > > > > That could cause problems; I'll look into it. > > > > > What it sounds like is that I shouldn't use "high rate" (for some > > > definition thereof -- more than the clock irqs?) things to feed > > > the entropy pool. That probably ought to be documented somewhere. > > > > I'll fix that too :-). I think that it would be better to fix the underlying problem, if possible; during a news expire with NFS archiving, the PCI irq can run as high as 300-400/s for most of an hour. I suppose the safest things to hook would be the keyboard irq (1) and the mouse (12 -- pms). But if there really is some kind of race condition in there, which is how it smells, then for max stability none is the right answer. > If I recall correctly, this _was_ documented before we moved from > /etc/sysconfic to /etc/rc.conf (basically, becuse we went from > "sections" with long descriptions for each option to single lines for > each option). It also specifically mentioned not to hook interrupts > attached to serial ports or the clock, I think. Interesting. It still seems that it oughta be safe for j. random (pun half-intended) sysadmin to hook whatever they like. The timers aren't good sources of entropy simply because of their periodicity. The same really *isn't* true, even for high-bandwidth serial ports, because there will always be the vagaries of network timing, non-busy periods, etc. Seems like a pretty good source, except that it makes the box fall over. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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