From: Stephane Eranian <eranian@hpl.hp.com>
To: Chuck Ebbert <76306.1226@compuserve.com>
Cc: linux-kernel <linux-kernel@vger.kernel.org>,
Linus Torvalds <torvalds@osdl.org>, Andi Kleen <ak@suse.de>
Subject: Re: [PATCH] i386 TIF flags for debug regs and io bitmap in ctxsw (v2)
Date: Tue, 25 Jul 2006 13:18:45 -0700 [thread overview]
Message-ID: <20060725201845.GH19928@frankl.hpl.hp.com> (raw)
In-Reply-To: <200607251522_MC3-1-C616-70EB@compuserve.com>
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
next prev parent reply other threads:[~2006-07-25 20:27 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-07-25 19:19 Chuck Ebbert
2006-07-25 20:18 ` Stephane Eranian [this message]
-- strict thread matches above, loose matches on Subject: below --
2006-07-04 7:29 [PATCH 2/2] i386 TIF flags for debug regs and io bitmap in ctxsw Stephane Eranian
2006-07-05 11:54 ` [PATCH] i386 TIF flags for debug regs and io bitmap in ctxsw (v2) Stephane Eranian
2006-07-25 5:54 ` Stephane Eranian
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