Re: [PATCH tip/core/rcu 0/4] Programmatic nestable expedited grace periods

From: Josh Triplett
Date: Sun Feb 22 2015 - 13:49:03 EST

On Sun, Feb 22, 2015 at 10:31:26AM -0800, Arjan van de Ven wrote:
> >>To show the boot time, I'm using the timestamp of the "Write protecting" line,
> >>that's pretty much the last thing we print prior to ring 3 execution.
> >
> >That's a little sad; we ought to be write-protecting kernel read-only
> >data as *early* as possible.
> well... if you are compromised before the first ring 3 instruction...
> .... you have a slightly bigger problem than where in the kernel we write protect things.

Definitely not talking about malicious compromise here; malicious code
could just remove the write protection. However, write-protecting
kernel read-only data also protects against a class of bugs.

- Josh Triplett
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