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Date: Fri, 26 Dec 1997 15:11:23 +1100
From: Bruce Evans <bde@zeta.org.au>
Message-Id: <199712260411.PAA06178@godzilla.zeta.org.au>
To: dima@tejblum.dnttm.rssi.ru, hoek@FreeBSD.ORG
Subject: Re: kern/2412
Cc: freebsd-bugs@FreeBSD.ORG, h-nokubi@nmit.mt.nec.co.jp
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>Rather than trying to guess wether the code is meant to be
>compiled or is just stale, I'll move it into feedback and just
>double-check that USER_LDT was supposed to have been configured.
>
>Is there someone specific responsible for the USER_LDT stuff who
>would be aware of potentially wrong code, or is it worth leaving
>the pr open just for that?

No one specific is responsible, but USER_LDT is obviously quite
broken without the option being visible.  fork(), exec() and exit()
are broken.  fork()ing with an active user LDT at best leaves 2
processes sharing the LDT.  exec()ing with an active LDT leaks
memory and privilege.  exit()Ing with an active LDT leaks memory.
I guess wine doesn't change the user LDT often enough for the bugs
to do more than leak memory.

I'd like testing of misconfigured options to be fatal but can't see
a good way to implement it.  A bad way:
- in opt_global.h, define each option that doesn't belong in opt_global.h
  as an expression with a syntax error.
- redefine the expression in each opt_foo.h file (same as now, except
  for an #undef to prevent a warning).
- change each test of an option to use `#if' to ensure an error if the
  expression is not defined properly.

Bruce