Re: [PATCH] x86/kconfig/32: Mark CONFIG_VM86 as BROKEN

From: Arjan van de Ven
Date: Tue Jul 07 2015 - 22:34:08 EST


On 7/7/2015 6:25 PM, Andy Lutomirski wrote:
VM86 is entirely broken if ptrace, syscall auditing, or NOHZ_FULL is
in use. The code is a big undocumented mess, it's a real PITA to
test, and it looks like a big chunk of vm86_32.c is dead code. It
also plays awful games with the entry asm.

No one should be using it anyway. Use DOSBOX or KVM instead.

Mark it BROKEN. I want to remove some (obviously incorrect) exit
asm that it depends on, and I don't want to figure out how to run
severely obsolete programs just to test something that no one uses
for anything other than exploits anyway.


while it is never great to deprecate features, in this case I am not sure
there is another choice unless someone steps up to seriously revamp this code.
(and look at it from a PREEMPT, NO_HZ etc etc angle)

if this patch would not be acceptable, at minimum we need some sort of "off by default
unless the sysadmin flips a sysfs thing", which is really just a huge hack.


so for me this is

Acked-by: Arjan van de Ven <arjan@xxxxxxxxxxxxxxx>


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