AMD chip bug snares Linux users

And how to fix it

An old bug in AMD’s Athlon family of chips may still be snaring Linux users.

Affected users will need to be running a 2.4 kernel, an AGP and an Athlon or Duron CPU. At cause is a compatibility issue with Intel’s 4MB page size. (x86 processors have used 4k pages, ever since paging was introduced in the 80386).

AMD issued a patch for Windows users in Fall 2000, with an accompanying PDF [13k].

But all the patch is, is a one-line registry change, described here, that only disables the expanded page size. And not all Pentium-specific instructions.

For Linux users, it's a one line workaround, too. Pass the line “append mem=nopentium” at boot time (via your boot loader of choice), to disable all Pentium specific instructions.

French distro Gentoo reported this yesterday, and found itself Slashdotted into the netherworld. It's still down, as we write. ®