Re: [patch] x86: fix ESP corruption CPU bug

Stas Sergeev
2005-03-14T04:52:49Z

Hi,

Linus Torvalds wrote:
> Btw, Stas, one thing I'd really like to see is even a partial list of
> anything that actually cares about this. Ie, if there is some known
> Windows app where Wine works better or something like that, just adding
I am not using Wine too much, but I've
found this:
http://cvs.winehq.org/cvsweb/~checkout~/wine/dlls/winedos/int31.c?rev=1.41&content-type=text/plain
---
/* due to a flaw in some CPUs (at least mine), it is best to mark stack segments as 32-bit if they
can be used in 32-bit code. Otherwise, these CPUs may not set the high word of esp during a
ring transition (from kernel code) to the 16-bit stack, and this causes trouble if executing
32-bit code using this stack. */
---
I added win-devel to CC, maybe people there
can tell if that patch has any value for them
or not.
The reference to the original patch:
http://www.uwsg.iu.edu/hypermail/linux/kernel/0503.1/1794.html

Dosemu looks a little better on that, the
whole chapter of the docs is dedicated to
that problem:
http://dosemu.sourceforge.net/docs/EMUfailure/t1.html#AEN55
There you can find a (relatively small)
list of the programs that are affected,
but I personally have the old Microsoft
linker that crashes, and a few more DOS
games.

> Another way of saying the same thing: I absolutely hate seeing patches
> that fix some theoretical issue that no Linux apps will ever care about.
No, it is not theoretical, but it is mainly
about a DOS games and an MS linker, as for
me. The things I'd like to get working, but
the ones you may not care too much about:)
The particular game I want to get working,
is "Master of Orion 2" for DOS.

> So I'd like to have a bit more of a case for this patch, since I know what
> the case against it is ;)
Yep, and the informational leak it closes,
looks also rather minor.
So it is only a matter of how do you care
about the dosemu and the DOS games under
linux. Considering the amount of the
dosemu-related code in vm86.c, I guess you
care:)
And uhm, adding the list of the DOS games
to the comments of the Linux kernel code,
doesn't sound like a good idea to me:)