Re: [patch 00/20] x86, ptrace, bts, hw-branch-tracer: fixes andcleanups

From: Ingo Molnar
Date: Fri Apr 03 2009 - 11:36:43 EST



* markus.t.metzger@xxxxxxxxx <markus.t.metzger@xxxxxxxxx> wrote:

> Patches 1-5 fix races with context switching code when the branch
> traced task is currently running.
>
> In the worst case, this might cause context switch code to access
> freed memory or the tracing hardware to continue tracing into a
> freed buffer. Both might crash the kernel.
>
> The first 4 patches apply to .29 using the below preparation
> patch.
>
> The remaining patches fix bugs in the context of per-cpu tracing
> (i.e. hw-branch-tracer) and pebs, add more selftest code, and do
> some cleanups.

Thanks - this looks pretty acceptable. Latest -git changed a lot of
code in the same area (-mm bits went upstream), creating a lot of
conflicts.

To not prolongue this any longer (20 patches are difficult enough
already to handle) i picked up your patches and resolved the
conflicts in situ - mind having a look at the resulting
tip:tracing/hw-branch-tracing branch - does the end result look sane
to you?

It would also be nice to address Peter's feedback about the mm.h
detail and the locked-pages API - but we can do that on top.

Thanks,

Ingo
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