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From: Jeff Dike <jdike@addtoit.com>
To: Chuck Ebbert <76306.1226@compuserve.com>
Cc: linux-kernel <linux-kernel@vger.kernel.org>,
	Roland McGrath <roland@redhat.com>,
	Linus Torvalds <torvalds@osdl.org>
Subject: Re: What is ptrace flag PT_TRACESYSGOOD for?
Date: Tue, 14 Mar 2006 15:00:55 -0500	[thread overview]
Message-ID: <20060314200055.GA22286@ccure.user-mode-linux.org> (raw)
In-Reply-To: <200603140531_MC3-1-BAA0-B3C3@compuserve.com>

On Tue, Mar 14, 2006 at 05:26:52AM -0500, Chuck Ebbert wrote:
> I am trying to document PTRACE_SETOPTIONS and I can't figure out what
> the option PTRACE_O_TRACESYSGOOD is used for.

It makes it easier to distinguish between the child receiving a
SIGTRAP and making a system call.  On x86, without TRACESYSGOOD, you
can see if orig_eax == -1 to check for a real SIGTRAP.  I'm not sure
about the other arches, but it's nice to have an arch-independent way
of doing it, even if there are equivalents in every arch.

				Jeff

  parent reply	other threads:[~2006-03-14 20:00 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-03-14 10:26 What is ptrace flag PT_TRACESYSGOOD for? Chuck Ebbert
2006-03-14 14:01 ` Charles P. Wright
2006-03-14 20:00 ` Jeff Dike [this message]
2006-03-14 23:00 ` Pavel Machek
2006-03-15  1:13   ` Jeff Dike

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