From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757593Ab0HaPc3 (ORCPT ); Tue, 31 Aug 2010 11:32:29 -0400 Received: from mx1.redhat.com ([209.132.183.28]:5525 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757583Ab0HaPc1 (ORCPT ); Tue, 31 Aug 2010 11:32:27 -0400 Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <20100831151212.GB2421@linux.vnet.ibm.com> References: <20100831151212.GB2421@linux.vnet.ibm.com> <20100830172631.GA11868@linux.vnet.ibm.com> <7899.1283259751@redhat.com> To: paulmck@linux.vnet.ibm.com Cc: dhowells@redhat.com, linux-kernel@vger.kernel.org, mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca, josh@joshtriplett.org, dvhltc@us.ibm.com, niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, Valdis.Kletnieks@vt.edu, eric.dumazet@gmail.com, jslaby@suse.cz, jmorris@namei.org Subject: Re: [PATCH RFC] pid: make setpgid() system call use RCU read-side critical section Date: Tue, 31 Aug 2010 16:31:29 +0100 Message-ID: <10401.1283268689@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Paul E. McKenney wrote: > It turns out that the setpgid() system call fails to enter an RCU > read-side critical section before doing a PID-to-task_struct translation. > This commit therefore does rcu_read_lock() before the translation, and > also does rcu_read_unlock() after the last use of the returned pointer. > > Reported-by: Andrew Morton > Signed-off-by: Paul E. McKenney Acked-by: David Howells