Date: Fri, 7 Nov 1997 14:10:26 -0800 (PST) From: Howard Lew <digital@www2.shoppersnet.com> To: Julian Elischer <julian@whistle.com> Cc: hackers@FreeBSD.ORG Subject: Re: Newest Pentium bug (fatal) Message-ID: <Pine.BSF.3.91.971107140742.8671A-100000@www2.shoppersnet.com> In-Reply-To: <3463605C.41C67EA6@whistle.com>
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On Fri, 7 Nov 1997, Julian Elischer wrote: > 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? On a Cyrix 6x86MX, it just dumps core: Illegal instruction (core dumped) > > 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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