Re: [tip:x86/asm] x86/entry/32: Switch INT80 to the new C syscall path

[Andy Lutomirski]

On Fri, Oct 16, 2015 at 11:22 AM, Brian Gerst <brgerst@xxxxxxxxx> wrote:
> On Fri, Oct 16, 2015 at 1:34 PM, Borislav Petkov <bp@xxxxxxxxx> wrote:
>> On Fri, Oct 16, 2015 at 08:59:23AM -0700, Andy Lutomirski wrote:
>>> Wow I am incompetent.
>>
>> Bah, it can happen to anyone...
>>
>>>     set_system_trap_gate(IA32_SYSCALL_VECTOR, entry_INT80_32);
>>>
>>> How did I not catch that in testing?  Can you change that to
>>> set_system_intr_gate and see if that helps?
>>
>> Yeah, that was it. Well spotted, thanks!
>
> The INT80 handler doesn't do anything that requires interrupts to be
> off (it is already on the process stack), so the tracing should be
> fixed to expect interrupts on. do_int80_syscall_32() can be eliminated
> too.

Good point.  Then we blow up in potentially interesting ways if an
iopl-using process does int80 with interrupts off.  Oh well.

--Andy
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/