Re: [PATCH v2 2/3] x86/entry/64: Teach idtentry to use the IRQ stack

From: Borislav Petkov
Date: Tue Jul 28 2015 - 05:50:37 EST


On Fri, Jul 24, 2015 at 10:57:05PM -0700, Andy Lutomirski wrote:
> We don't specifically need IST for things like kprobes, but we do
> want to avoid rare, surprising extra stack usage if a kprobe hits
> with a deep stack.
>
> Teach idtentry to use the IRQ stack for selected entries.
>
> This implementation uses the IRQ stack even if we entered from user
> mode. This disallows tricks like ist_begin_non_atomic. If we ever
> need such a trick in one of these entries, we can rework this. For
> now, let's keep it simple.
>
> Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx>
> ---
> arch/x86/entry/entry_64.S | 14 +++++++++++++-
> 1 file changed, 13 insertions(+), 1 deletion(-)

Reviewed-by: Borislav Petkov <bp@xxxxxxx>

--
Regards/Gruss,
Boris.

ECO tip #101: Trim your mails when you reply.
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