Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757338Ab1CRTAI (ORCPT ); Fri, 18 Mar 2011 15:00:08 -0400 Received: from e1.ny.us.ibm.com ([32.97.182.141]:51132 "EHLO e1.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756995Ab1CRTAA (ORCPT ); Fri, 18 Mar 2011 15:00:00 -0400 Date: Sat, 19 Mar 2011 00:23:14 +0530 From: Srikar Dronamraju To: Peter Zijlstra Cc: Steven Rostedt , Thomas Gleixner , Ingo Molnar , Linux-mm , Arnaldo Carvalho de Melo , Linus Torvalds , Christoph Hellwig , Masami Hiramatsu , Ananth N Mavinakayanahalli , Oleg Nesterov , LKML , SystemTap , Jim Keniston , Roland McGrath , Andi Kleen , Andrew Morton , "Paul E. McKenney" Subject: Re: [PATCH v2 2.6.38-rc8-tip 5/20] 5: Uprobes: register/unregister probes. Message-ID: <20110318185314.GB24048@linux.vnet.ibm.com> Reply-To: Srikar Dronamraju References: <20110314133403.27435.7901.sendpatchset@localhost6.localdomain6> <20110314133454.27435.81020.sendpatchset@localhost6.localdomain6> <20110315171536.GA24254@linux.vnet.ibm.com> <1300211262.9910.295.camel@gandalf.stny.rr.com> <1300211411.2203.290.camel@twins> <20110315180423.GA10429@linux.vnet.ibm.com> <1300212949.2203.324.camel@twins> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <1300212949.2203.324.camel@twins> User-Agent: Mutt/1.5.20 (2009-06-14) X-Content-Scanned: Fidelis XPS MAILER Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1321 Lines: 28 > > > > One of the install_uprobe could be failing because the process was > > almost exiting, something like there was no mm->owner. Also lets > > assume that the first few install_uprobes go thro and the last > > install_uprobe fails. There could be breakpoint hits corresponding to > > the already installed uprobes that get displayed. i.e all > > breakpoint hits from the first install_uprobe to the time we detect a > > failed a install_uprobe and revert all inserted breakpoints will be > > shown as being captured. > > I think you can gracefully deal with the exit case and simply ignore > that one. But you cannot let arbitrary installs fail and still report > success, that gives very weak and nearly useless semantics. If there are more than one instance of a process running and if one instance of a process has a probe thro ptrace, install_uprobe would fail for that process with -EEXIST since we dont want to probe locations that have breakpoints already. Should we then act similar to the exit case, do we also deal gracefully? -- Thanks and Regards Srikar -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/