Messages in this thread | | | From | Andy Lutomirski <> | Date | Fri, 10 Apr 2015 16:15:39 -0700 | Subject | Re: [PATCH 4/8] x86: Add support for rd/wr fs/gs base |
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On Fri, Apr 10, 2015 at 4:05 PM, Andi Kleen <andi@firstfloor.org> wrote: >> One might argue that this code serves no purpose, but it's there, so >> we had better keep our per-invocation usage of DEBUG_STACK within 4k. > > Only if you run NKLD. I doubt KDB or GDB support nesting. > We can ask Jan if he still uses it.
You can trigger these things in various ways with kprobes, single-stepping, and user-space watchpoints. These things can definitely nest in interesting ways. Whether or not the IST shift mechanism is involved if they nest is a complicated question, because there's also the "debug" IDT in play.
OMG this code is overcomplicated.
--Andy
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