Re: [RFC] x86_64: A real proposal for iret-less return to kernel

[Borislav Petkov]

On Wed, May 21, 2014 at 02:52:55PM -0700, Andy Lutomirski wrote:
> Why is it a problem if user_mode_vm(regs)?  Conversely, why is sending
> a signal a remotely reasonable thing to do if !user_mode_vm(regs)?

Let me quote Jiri:

(1) task sends signal to itself
(2) it acquires sighand->siglock so that it's able to queue the signal
(3) MCE triggers
(4) it tries to send a signal to the same task
(5) it tries to acquire sighand->siglock and loops forever

-- 
Regards/Gruss,
    Boris.

Sent from a fat crate under my desk. Formatting is fine.
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