Messages in this thread | | | Date | Thu, 1 May 2014 23:15:54 +0200 | From | Andi Kleen <> | Subject | Re: [PATCH 4/7] x86: Add support for rd/wr fs/gs base |
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> If usergs == kernelgs, then ebx will always be 1 and we'll never end > up in paranoid_userspace.
You may miss a reschedule in this obscure case. It shouldn't really happen because loading a kernel pointer is not useful for user space.
Doesn't seem like a real issue to me.
We only happen need to handle it to avoid crashing.
> Alternatively, what if the paranoid entry checked whether we're coming > from userspace at the very beginning and, if so, just jumped to the > non-paranoid entry?
That would work, but I doubt it would be worth it.
-Andi
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