From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757908AbZLNQcK (ORCPT ); Mon, 14 Dec 2009 11:32:10 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755103AbZLNQcH (ORCPT ); Mon, 14 Dec 2009 11:32:07 -0500 Received: from hera.kernel.org ([140.211.167.34]:34081 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757886AbZLNQcE (ORCPT ); Mon, 14 Dec 2009 11:32:04 -0500 Date: Mon, 14 Dec 2009 16:31:35 GMT From: tip-bot for Thomas Gleixner Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@redhat.com, peterz@infradead.org, tglx@linutronix.de, mingo@elte.hu Reply-To: mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, peterz@infradead.org, tglx@linutronix.de, mingo@elte.hu In-Reply-To: <20091209100706.862897167@linutronix.de> References: <20091209100706.862897167@linutronix.de> To: linux-tip-commits@vger.kernel.org Subject: [tip:sched/urgent] sched: Use rcu in sched_get_rr_param() Message-ID: Git-Commit-ID: 1a551ae715825bb2a2107a2dd68de024a1fa4e32 X-Mailer: tip-git-log-daemon MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 1a551ae715825bb2a2107a2dd68de024a1fa4e32 Gitweb: http://git.kernel.org/tip/1a551ae715825bb2a2107a2dd68de024a1fa4e32 Author: Thomas Gleixner AuthorDate: Wed, 9 Dec 2009 10:15:11 +0000 Committer: Ingo Molnar CommitDate: Mon, 14 Dec 2009 17:11:35 +0100 sched: Use rcu in sched_get_rr_param() read_lock(&tasklist_lock) does not protect sys_sched_get_rr_param() against a concurrent update of the policy or scheduler parameters as do_sched_scheduler() does not take the tasklist_lock. The access to task->sched_class->get_rr_interval is protected by task_rq_lock(task). Use rcu_read_lock() to protect find_task_by_vpid() and prevent the task struct from going away. Signed-off-by: Thomas Gleixner Cc: Peter Zijlstra LKML-Reference: <20091209100706.862897167@linutronix.de> Signed-off-by: Ingo Molnar --- kernel/sched.c | 6 +++--- 1 files changed, 3 insertions(+), 3 deletions(-) diff --git a/kernel/sched.c b/kernel/sched.c index 7989312..db5c266 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -6873,7 +6873,7 @@ SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid, return -EINVAL; retval = -ESRCH; - read_lock(&tasklist_lock); + rcu_read_lock(); p = find_process_by_pid(pid); if (!p) goto out_unlock; @@ -6886,13 +6886,13 @@ SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid, time_slice = p->sched_class->get_rr_interval(rq, p); task_rq_unlock(rq, &flags); - read_unlock(&tasklist_lock); + rcu_read_unlock(); jiffies_to_timespec(time_slice, &t); retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0; return retval; out_unlock: - read_unlock(&tasklist_lock); + rcu_read_unlock(); return retval; }