From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail144.messagelabs.com (mail144.messagelabs.com [216.82.254.51]) by kanga.kvack.org (Postfix) with ESMTP id 4F1218D0040 for ; Fri, 25 Mar 2011 22:35:03 -0400 (EDT) Received: from wpaz33.hot.corp.google.com (wpaz33.hot.corp.google.com [172.24.198.97]) by smtp-out.google.com with ESMTP id p2Q2Z1TE010894 for ; Fri, 25 Mar 2011 19:35:01 -0700 Received: from iwc10 (iwc10.prod.google.com [10.241.65.138]) by wpaz33.hot.corp.google.com with ESMTP id p2Q2Yvkp012379 (version=TLSv1/SSLv3 cipher=RC4-SHA bits=128 verify=NOT) for ; Fri, 25 Mar 2011 19:35:00 -0700 Received: by iwc10 with SMTP id 10so1834178iwc.38 for ; Fri, 25 Mar 2011 19:34:57 -0700 (PDT) Date: Fri, 25 Mar 2011 19:34:52 -0700 From: Michel Lespinasse Subject: Re: [PATCH 0/4] forkbomb killer Message-ID: <20110326023452.GA8140@google.com> References: <20110324182240.5fe56de2.kamezawa.hiroyu@jp.fujitsu.com> <20110324105222.GA2625@barrios-desktop> <20110325090411.56c5e5b2.kamezawa.hiroyu@jp.fujitsu.com> <20110325115453.82a9736d.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Minchan Kim Cc: KAMEZAWA Hiroyuki , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "rientjes@google.com" , Andrey Vagin , KOSAKI Motohiro , Hugh Dickins , Johannes Weiner , Rik van Riel On Fri, Mar 25, 2011 at 01:05:50PM +0900, Minchan Kim wrote: > Okay. Each approach has a pros and cons and at least, now anyone > doesn't provide any method and comments but I agree it is needed(ex, > careless and lazy admin could need it strongly). Let us wait a little > bit more. Maybe google guys or redhat/suse guys would have a opinion. I haven't heard of fork bombs being an issue for us (and it's not been for me on my desktop, either). Also, I want to point out that there is a classical userspace solution for this, as implemented by killall5 for example. One can do kill(-1, SIGSTOP) to stop all processes that they can send signals to (except for init and itself). Target processes can never catch or ignore the SIGSTOP. This stops the fork bomb from causing further damage. Then, one can look at the process tree and do whatever is appropriate - including killing by uid, by cgroup or whatever policies one wants to implement in userspace. Finally, the remaining processes can be restarted using SIGCONT. -- Michel "Walken" Lespinasse A program is never fully debugged until the last user dies. -- 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