From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail6.bemta8.messagelabs.com (mail6.bemta8.messagelabs.com [216.82.243.55]) by kanga.kvack.org (Postfix) with ESMTP id 480696B00EB for ; Thu, 16 Jun 2011 00:19:50 -0400 (EDT) Received: from d01relay01.pok.ibm.com (d01relay01.pok.ibm.com [9.56.227.233]) by e3.ny.us.ibm.com (8.14.4/8.13.1) with ESMTP id p5G3vDer023030 for ; Wed, 15 Jun 2011 23:57:13 -0400 Received: from d01av04.pok.ibm.com (d01av04.pok.ibm.com [9.56.224.64]) by d01relay01.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id p5G4Jn3Y136268 for ; Thu, 16 Jun 2011 00:19:49 -0400 Received: from d01av04.pok.ibm.com (loopback [127.0.0.1]) by d01av04.pok.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id p5G4Jg9K023500 for ; Thu, 16 Jun 2011 00:19:48 -0400 Date: Thu, 16 Jun 2011 09:41:37 +0530 From: Srikar Dronamraju Subject: Re: [PATCH v4 3.0-rc2-tip 4/22] 4: Uprobes: register/unregister probes. Message-ID: <20110616041137.GG4952@linux.vnet.ibm.com> Reply-To: Srikar Dronamraju References: <20110607125804.28590.92092.sendpatchset@localhost6.localdomain6> <20110607125900.28590.16071.sendpatchset@localhost6.localdomain6> <1308159719.2171.57.camel@laptop> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <1308159719.2171.57.camel@laptop> Sender: owner-linux-mm@kvack.org List-ID: To: Peter Zijlstra Cc: Ingo Molnar , Steven Rostedt , Linux-mm , Arnaldo Carvalho de Melo , Linus Torvalds , Ananth N Mavinakayanahalli , Hugh Dickins , Christoph Hellwig , Jonathan Corbet , Thomas Gleixner , Masami Hiramatsu , Oleg Nesterov , Andrew Morton , Jim Keniston , Roland McGrath , Andi Kleen , LKML * Peter Zijlstra [2011-06-15 19:41:59]: > On Tue, 2011-06-07 at 18:29 +0530, Srikar Dronamraju wrote: > > 1. Use mm->owner and walk thro the thread_group of mm->owner, siblings > > of mm->owner, siblings of parent of mm->owner. This should be > > good list to traverse. Not sure if this is an exhaustive > > enough list that all tasks that have a mm set to this mm_struct are > > walked through. > > As per copy_process(): > > /* > * Thread groups must share signals as well, and detached threads > * can only be started up within the thread group. > */ > if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND)) > return ERR_PTR(-EINVAL); > > /* > * Shared signal handlers imply shared VM. By way of the above, > * thread groups also imply shared VM. Blocking this case allows > * for various simplifications in other code. > */ > if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM)) > return ERR_PTR(-EINVAL); > > CLONE_THREAD implies CLONE_VM, but not the other way around, we > therefore would be able to CLONE_VM and not be part of the primary > owner's thread group. > > This is of course all terribly sad.. Agree, If clone(CLONE_VM) were to be done by a thread_group leader, we can walk thro the siblings of parent of mm->owner. However if clone(CLONE_VM) were to be done by non thread_group_leader thread, then we dont even seem to add it to the init_task. i.e I dont think we can refer to such a thread even when we walk thro do_each_thread(g,t) { .. } while_each_thread(g,t); right? -- Thanks and Regards Srikar -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org