Re: Fast Pentium memcpy() corruption bug appears to be fixed (finally!)

H. Peter Anvin (hpa@freya.yggdrasil.com)
4 Mar 1996 14:04:11 GMT

Followup to: <199603040041.TAA03610@rlk-ppp-1.aptinc.com>
By author: Robert L Krawitz <rlk@tiac.net>
In newsgroup: linux.dev.kernel
>
> I believe that I have fixed the corruption problem with my fast
> memcpy() routine. The fix was to force the routine to read the first
> word from both the source and destination block with conventional
> instructions first. I did this in the belief that the problem was du=
e
> to a page fault at the wrong time (since this only seemed to happen
> when the machine was under significant load). My guess appears (so
> far) to be correct. I ran my usual test (two separate cvs diff's of
> the Linux kernel concurrently) without any failures. I repeated it
> with 7 concurrent cvs diff's, and had no errors, either.
>=20

I saw on your page you use the FPU registers. How does that do with
respect to the "lazy FPU regdump" feature?

-hpa
--=20
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