From owner-freebsd-hackers@FreeBSD.ORG Sat Jul 10 19:44:01 2004 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 9EAC516A4CE for ; Sat, 10 Jul 2004 19:44:01 +0000 (GMT) Received: from ppsw-0.csi.cam.ac.uk (ppsw-0.csi.cam.ac.uk [131.111.8.130]) by mx1.FreeBSD.org (Postfix) with ESMTP id 3FA2643D39 for ; Sat, 10 Jul 2004 19:44:01 +0000 (GMT) (envelope-from sos22@cantab.net) Received: from archibold.chu.cam.ac.uk ([131.111.131.102]:50842) by ppsw-0.csi.cam.ac.uk (smtp.hermes.cam.ac.uk [131.111.8.150]:25) with smtp (Exim 4.34) id 1BjNlO-00089b-NX; Sat, 10 Jul 2004 20:43:58 +0100 Received: by archibold.chu.cam.ac.uk (sSMTP sendmail emulation); Sat, _d Jul 2004 20:45:14 +0100 Date: Sat, 10 Jul 2004 20:45:14 +0100 From: Steven Smith To: freebsd-hackers@freebsd.org Message-ID: <20040710194456.GA3366@archibold.chu.cam.ac.uk> References: <20040708091417.GA967@archibold.chu.cam.ac.uk> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="bCsyhTFzCvuiizWE" Content-Disposition: inline In-Reply-To: X-Cam-ScannerInfo: http://www.cam.ac.uk/cs/email/scanner/ X-Cam-AntiVirus: No virus found X-Cam-SpamDetails: Not scanned cc: sos22@srcf.ucam.org Subject: Re: Article on Sun's DTrace X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 10 Jul 2004 19:44:01 -0000 --bCsyhTFzCvuiizWE Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable > > It's also possible to put probes on the return instruction of the > > function. I'm not sure how they're actually finding that, though. > I think the return probe is done by adding a call probe that changes the= =20 > return address. Yeah, I thought that when I first saw it, but the probe is passed the address of the return instruction when it fires, and I can't see how you could get that if it was just invoked by modifying the return address on the call stack. Steven. --bCsyhTFzCvuiizWE Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.4 (FreeBSD) iD8DBQFA8EdJO4S8/gLNrjcRAvpkAKDVH8gsqwNNpP2JNtnCQ9V22cU/xQCdHtWb HnzXxbqI7GP41xPKjhRdj0Y= =4Eza -----END PGP SIGNATURE----- --bCsyhTFzCvuiizWE--