From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sukadev Bhattiprolu Subject: Re: [PATCH][usercr]: Ghost tasks must be detached Date: Thu, 10 Feb 2011 14:31:59 -0800 Message-ID: <20110210223159.GA4544@us.ibm.com> References: <4D2BB78A.9090701@cs.columbia.edu> <4D4D9D1B.3000209@cs.columbia.edu> <20110205214032.GA12944@us.ibm.com> <4D4DC90B.3010103@cs.columbia.edu> <20110209020942.GA5339@us.ibm.com> <20110209120100.GD13323@hawkmoon.kerlabs.com> <20110209190216.GA17051@us.ibm.com> <20110210102312.GC6360@hawkmoon.kerlabs.com> <20110210175409.GB1025@us.ibm.com> <20110210180433.GI6360@hawkmoon.kerlabs.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20110210180433.GI6360-Hu8+6S1rdjywhHL9vcZdMVaTQe2KTcn/@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Oren Laadan , Containers List-Id: containers.vger.kernel.org Louis Rilling [Louis.Rilling-aw0BnHfMbSpBDgjK7y7TUQ@public.gmane.org] wrote: | On 10/02/11 9:54 -0800, Sukadev Bhattiprolu wrote: | > Louis Rilling [Louis.Rilling-aw0BnHfMbSpBDgjK7y7TUQ@public.gmane.org] wrote: | > If it was a detached task, do_wait_thread() skipped over it. In the C/R | > kernel we were setting the ->exit_signal to -1 for a "ghost" process. | > I assumed that the container-init exited without waiting for the "ghost" | > and we were getting the crash in proc_flush_mnt() when the ghost exited. | | The point is that wait_consider_task() skips detached tasks as soon as they are | not ptraced. So removing the check in do_wait_thread() should not have changed | the behavior. Am I missing something? No. I was :-) You are right that it did not change the behavior. I still need to investigate why the crash does not occur on 2.6.37 even without Eric's fix. Sukadev