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From: Jeff Dike <jdike@addtoit.com>
To: Pavel Machek <pavel@ucw.cz>
Cc: Chuck Ebbert <76306.1226@compuserve.com>,
	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 20:13:12 -0500	[thread overview]
Message-ID: <20060315011312.GA9410@ccure.user-mode-linux.org> (raw)
In-Reply-To: <20060314230056.GA1579@elf.ucw.cz>

On Wed, Mar 15, 2006 at 12:00:56AM +0100, Pavel Machek wrote:
> Yes.. and unless you deliver ptrace() syscall stops with different
> signal, you can't tell difference between syscall stop and real
> SIGTRAP.

You can, but you have to examine registers in order to do this.  This
is a concern when running gdb inside UML.  gdb breakpoints will cause
real SIGTRAPs, while system calls cause synthetic ones.  Before
switching to TRACESYS_GOOD, UML examined orig_eax to distinguish
between them.

				Jeff

      reply	other threads:[~2006-03-15  1:12 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
2006-03-14 23:00 ` Pavel Machek
2006-03-15  1:13   ` Jeff Dike [this message]

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