Re: [PATCH] i386 TIF flags for debug regs and io bitmap in ctxsw (v2)
From: Stephane Eranian
Date: Tue Jul 25 2006 - 16:25:47 EST
Chuck,
On Tue, Jul 25, 2006 at 03:19:49PM -0400, Chuck Ebbert wrote:
>
> > As for TIF_DEBUG, my patch is not clearing it. I don't think you can
> > have HW breakpoints be inherited from one task to the other.
>
> Looks like the debug regs get copied on fork and only cleared on exec
> in flush_thread(). So this should be OK. Please doublecheck.
>
How is this supposed to work? You can set debug registers via ptrace().
So A is ptracing B and sets up breakpoints in B. Now, if B forks C,
C inherits the breakpoints of B. But what about the ptracing and re-parenting
that is associated with this? If A does not know about C, I wonder how this
could be work and be useful?
> (The new TIF_DEBUG flag went into 2.8.18-rc, in case you didn't notice.)
I did not keep track but thanks or this update. That's great!
--
-Stephane
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