Re: 2.6.12-rc3 OOPS in vanilla source (once more)

[Stas Sergeev]

Hello.

Alexander Nyberg wrote:
> /From my reading a task that is scheduled away cannot have a partial/
> saved pt_regs. If this is correct then ptrace won't suffer from this
> problem
This is most likely correct, I
just wanted to be sure.

> I need to look at the partial stack issue closer, don't think I fully
> understand it yet.
When the IRQ/NMI interrupts the
ring0 code (kernel), since the
handler is also ring0, the interrupt
gate doesn't save the SS and ESP
when switching, so you miss the 8 bytes.
After looking at the code again I
don't think this can affect the
ptrace since the ptrace probably
never traces from an IRQ context
(I hope).
So I think it is safe to ignore my
previous comment. (if only perhaps
the "optimized" version of the patch
is to have a look)

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