Re: [PATCH] x86, traps: install gates using IST after cpu_init().

[Andy Lutomirski]

On Wed, Feb 25, 2015 at 10:15 PM, Wang Nan <wangnan0@xxxxxxxxxx> wrote:
> X86_TRAP_NMI, X86_TRAP_DF and X86_TRAP_MC use their own stack. Those
> stacks are invalid until cpu_init() installs TSS.
>
> This patch moves setting of the 3 gates after cpu_init().
>
> Signed-off-by: Wang Nan <wangnan0@xxxxxxxxxx>
> ---
>
> If I understand correctly, logically speaking the original code is
> incorrect.  However, there is no real bug caused by it for serval years.
> I'm not sure whether this fix is practical or not. Fix them only for
> logical correctness.

Acked-by: Andy Lutomirski <luto@xxxxxxxxxxxxxx>

That being said, I'm pretty sure you're not fixing a bug here.
Delivery of an exception with no handler is every bit as fatal as
delivery of an exception with a non-working IST handler.

--Andy
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