Date: Fri, 7 Nov 1997 12:24:27 -0800 (PST) From: Jim Shankland <jas@flyingfox.com> To: hackers@FreeBSD.ORG, julian@whistle.com Subject: Re: Newest Pentium bug (fatal) Message-ID: <199711072024.MAA25720@biggusdiskus.flyingfox.com>
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Yow!
An old 66 MHz Pentium with the old floating-point bug (remember that one?):
* sayonara *
An almost new 166 MHz Pentium MMX:
* adios *
If this is really the processor halting in its tracks (as opposed to,
say, FreeBSD failing to handle some weird kind of trap), then this
may cost Intel some real money to fix. Compared with the aforementioned
floating-point bug, this seems like a much bigger deal.
Jim Shankland
Flying Fox Computer Systems, Inc.
> Date: Fri, 07 Nov 1997 10:39:24 -0800
> From: Julian Elischer <julian@whistle.com>
> Organization: Whistle Communications
> MIME-Version: 1.0
> To: hackers@FreeBSD.ORG
> Subject: Newest Pentium bug (fatal)
> Content-Type: text/plain; charset=us-ascii
> Content-Transfer-Encoding: 7bit
>
> On a "genuine Intel" pentium (not pentium pro)
> execution of the following sequence, 0xf0 0x0f 0xc7 0xc8
>
> will stop the processor. This is doable from user mode and in
> 16bitmode, or in fact any mode.
>
> try the following c program.
>
>
>
>
> unsigned char x[] = { 0xfo, 0x0f, 0xc7, 0xc8 };
>
>
> main ()
> {
> void (*f)(void) = x;
> f();
> }
>
>
>
>
> We've checked:
> K5... OK
> P6... OK
> P5... *SPLAT*
>
> no idea about the pentium II or other pentium copies.
> K6?
>
> other pentium variants?
> versions?
>
> this one DEFINITLY dies:
> CPU: Pentium (99.38-MHz 586-class CPU)
> Origin = "GenuineIntel" Id = 0x525 Stepping=5
> Features=0x1bf<FPU,VME,DE,PSE,TSC,MSR,MCE,CX8>
>
>
> share and enjoy..
>
> julian
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