From owner-freebsd-bugs@FreeBSD.ORG  Tue Nov 30 17:20:20 2004
Return-Path: <owner-freebsd-bugs@FreeBSD.ORG>
Delivered-To: freebsd-bugs@hub.freebsd.org
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP id 3177F16A4CE
	for <freebsd-bugs@hub.freebsd.org>;
	Tue, 30 Nov 2004 17:20:20 +0000 (GMT)
Received: from freefall.freebsd.org (freefall.freebsd.org [216.136.204.21])
	by mx1.FreeBSD.org (Postfix) with ESMTP id 1DA8F43D2D
	for <freebsd-bugs@hub.freebsd.org>;
	Tue, 30 Nov 2004 17:20:20 +0000 (GMT)
	(envelope-from gnats@FreeBSD.org)
Received: from freefall.freebsd.org (gnats@localhost [127.0.0.1])
	by freefall.freebsd.org (8.13.1/8.13.1) with ESMTP id iAUHKJwG087456
	for <freebsd-bugs@freefall.freebsd.org>; Tue, 30 Nov 2004 17:20:19 GMT
	(envelope-from gnats@freefall.freebsd.org)
Received: (from gnats@localhost)
	by freefall.freebsd.org (8.13.1/8.13.1/Submit) id iAUHKJrW087455;
	Tue, 30 Nov 2004 17:20:19 GMT
	(envelope-from gnats)
Date: Tue, 30 Nov 2004 17:20:19 GMT
Message-Id: <200411301720.iAUHKJrW087455@freefall.freebsd.org>
To: freebsd-bugs@FreeBSD.org
From: David Schultz <das@FreeBSD.ORG>
Subject: Re: kern/70708: gcore/procfs not finding /proc/pid/file on repeated
	invocations when running from NFS
X-BeenThere: freebsd-bugs@freebsd.org
X-Mailman-Version: 2.1.1
Precedence: list
Reply-To: David Schultz <das@FreeBSD.ORG>
List-Id: Bug reports <freebsd-bugs.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-bugs>,
	<mailto:freebsd-bugs-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-bugs>
List-Post: <mailto:freebsd-bugs@freebsd.org>
List-Help: <mailto:freebsd-bugs-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-bugs>,
	<mailto:freebsd-bugs-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Tue, 30 Nov 2004 17:20:20 -0000

The following reply was made to PR kern/70708; it has been noted by GNATS.

From: David Schultz <das@FreeBSD.ORG>
To: Volker Stolz <stolz@i2.informatik.rwth-aachen.de>
Cc: FreeBSD-gnats-submit@FreeBSD.ORG
Subject: Re: kern/70708: gcore/procfs not finding /proc/pid/file on repeated invocations when running from NFS
Date: Tue, 30 Nov 2004 12:14:39 -0500

 This is due to a bug in procfs.  Specifically, procfs uses
 vn_fullpath() to generate the appropriate symbolic link for
 /proc/$pid/file, and vn_fullpath() fails if one or more pathname
 components is missing from the name cache.  We cannot solve this
 problem in procfs without a fully functional getcwd()
 implementation in the kernel.
 
 However, for this particular problem, it may be possible to work
 around the problem in procfs, since the only reason gcore needs
 procfs is to determine if the binary is ELF or not.  Possible
 solutions:
 
 - Extend ptrace(2) to make it possible to open a traced process'
   text file without procfs.  This is generally a good idea anyway,
   because /proc/$pid/file will never work for processes whose text
   files have been unlinked from the file system.
 
 - Don't bother checking whether the binary is ELF or not, since
   gcore no longer supports a.out.  This would result in invalid
   dumps for non-ELF processes, and merely defers the problem until
   someone invents an ELF++ dump format.
 
 I have no time to work on this right now, so it would be great if
 someone could pick this up.