automated way to find functions that we might want to blacklist

[Sami Liedes]

On Tue, Jan 17, 2012 at 02:18:26PM -0600, David Smith wrote:
> There is nothing that those 2 functions do that can crash the kernel.
> Those functions (should be) always inlined.  I'd guess the problem isn't
> those two functions, but the function that is calling them.

Yes, I've figured as much that the crashes come from places where
these are inlined. But I had't thought about using .call; will do
that.

> Another problem I see with your testing methodology is that you are
> using xen.  I don't think we've used xen in a while, but the xen kernel
> always gave us different results than a regular kernel.  I'd test on
> bare metal or in a kvm instance.

Timo uses Xen, but I'm running the tests in KVM.

> I'll make one final comment here.  In my mind the blacklist is a
> semi-temporary thing (although we don't typically remove functions from
> it).  The real fix here is to get the crashing functions marked with
> '__kprobes' in the upstream kernel.  This fixes the problem for all
> kprobes users, not just systemtap.

Makes sense to me.

	Sami
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