[ros-dev] [ros-diffs] [sginsberg] 43958: - Fix the "fix" of un-protecting the 7 IDT entries on P5 in HAL's BIOS call code when setting the custom Invalid Opcode handler

[Dmitry Gorbachev]

> Ok...so how does it crash? And where? Can I get a backtrace or something?

First time, HalpBiosDisplayReset() is called when booting, before
KiI386PentiumLockErrataFixup(). Recent changes cause a page to be
protected from writing. Then kernel tries to write to this page and
crashes. Another time, HalpBiosDisplayReset() is called when shutting
down; before r39959, crash happened to be there. From r39959 and
before r43958, write protection was established only in
KiI386PentiumLockErrataFixup().

It appears that a fix for a fix for a fix is now needed:)