From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 30178 invoked by alias); 23 Aug 2008 14:09:07 -0000 Received: (qmail 30171 invoked by uid 22791); 23 Aug 2008 14:09:06 -0000 X-Spam-Status: No, hits=-2.3 required=5.0 tests=AWL,BAYES_00,KAM_MX,SPF_HELO_PASS,SPF_PASS X-Spam-Check-By: sourceware.org Received: from mx1.redhat.com (HELO mx1.redhat.com) (66.187.233.31) by sourceware.org (qpsmtpd/0.31) with ESMTP; Sat, 23 Aug 2008 14:08:32 +0000 Received: from int-mx1.corp.redhat.com (int-mx1.corp.redhat.com [172.16.52.254]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id m7NE8U3I004037; Sat, 23 Aug 2008 10:08:30 -0400 Received: from pobox-3.corp.redhat.com (pobox-3.corp.redhat.com [10.11.255.67]) by int-mx1.corp.redhat.com (8.13.1/8.13.1) with ESMTP id m7NE8TCQ010606; Sat, 23 Aug 2008 10:08:29 -0400 Received: from touchme.toronto.redhat.com (IDENT:postfix@touchme.yyz.redhat.com [10.15.16.9]) by pobox-3.corp.redhat.com (8.13.1/8.13.1) with ESMTP id m7NE84IV032696; Sat, 23 Aug 2008 10:08:29 -0400 Received: from ton.toronto.redhat.com (ton.yyz.redhat.com [10.15.16.15]) by touchme.toronto.redhat.com (Postfix) with ESMTP id 3B1808001FF; Sat, 23 Aug 2008 10:07:48 -0400 (EDT) Received: from ton.toronto.redhat.com (localhost.localdomain [127.0.0.1]) by ton.toronto.redhat.com (8.13.1/8.13.1) with ESMTP id m7NE7V0m012431; Sat, 23 Aug 2008 10:07:31 -0400 Received: (from fche@localhost) by ton.toronto.redhat.com (8.13.1/8.13.1/Submit) id m7NE7VI0012430; Sat, 23 Aug 2008 10:07:31 -0400 X-Authentication-Warning: ton.toronto.redhat.com: fche set sender to fche@redhat.com using -f To: "Peter Teoh" Cc: systemtap@sources.redhat.com, "Om Narasimhan" Subject: Re: systemtap question.. References: <48ACFC02.3080002@gmail.com> <804dabb00808222127t3606302ds94056e7da6b0f30d@mail.gmail.com> From: fche@redhat.com (Frank Ch. Eigler) Date: Sat, 23 Aug 2008 14:09:00 -0000 In-Reply-To: <804dabb00808222127t3606302ds94056e7da6b0f30d@mail.gmail.com> (Peter Teoh's message of "Sat, 23 Aug 2008 12:27:55 +0800") Message-ID: User-Agent: Gnus/5.1008 (Gnus v5.10.8) Emacs/21.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Scanned-By: MIMEDefang 2.58 on 172.16.52.254 Mailing-List: contact systemtap-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Post: List-Help: , Sender: systemtap-owner@sourceware.org X-SW-Source: 2008-q3/txt/msg00482.txt.bz2 "Peter Teoh" writes: > as discovered by narasimhan, the following script will lead to kernel > freezing and hanged for me: > I execute via "stap -kvvv script.stp" command. Please see the "HowToReportBugs" systemtap wiki page. > Question is: why does he get a compilation error when using the -u > option? (same for me as well, which goes away when removed?) >> probe kernel.function ("vfs_read"), kernel.function("vfs_write") >> { >> inode = $file->f_dentry->d_inode->i_ino >> dev_nr = $file->f_dentry->d_inode->i_sb->s_dev >> >> } The reason is that this probe does nothing. The "inode" and "dev_nr" variables being fetched are not printed, so systemtap figures they were not needed in the first place, and elides the $-expressions. The "-u" (unoptimized) flag preserves such code. - FChE