From: Oleg Nesterov <oleg@tv-sign.ru>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>,
"Eric W. Biederman" <ebiederm@xmission.com>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Pavel Emelyanov <xemul@sw.ru>,
linux-kernel@vger.kernel.org
Subject: [PATCH] do_task_stat: don't take rcu_read_lock()
Date: Wed, 20 Feb 2008 20:09:13 +0300 [thread overview]
Message-ID: <20080220170913.GA465@tv-sign.ru> (raw)
(depends on "[PATCH 1/2] lock_task_sighand: add rcu lock/unlock",
http://marc.info/?l=linux-kernel&m=120335433821564)
lock_task_sighand() was changed, and do_task_stat() doesn't need rcu_read_lock
any longer. sighand->siglock protects all "interesting" fields.
Except: it doesn't protect ->tty->pgrp, but neither does rcu_read_lock(), this
should be fixed.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
--- MM/fs/proc/array.c~DTS 2008-02-17 23:40:07.000000000 +0300
+++ MM/fs/proc/array.c 2008-02-20 19:53:37.000000000 +0300
@@ -425,7 +425,6 @@ static int do_task_stat(struct seq_file
cutime = cstime = utime = stime = cputime_zero;
cgtime = gtime = cputime_zero;
- rcu_read_lock();
if (lock_task_sighand(task, &flags)) {
struct signal_struct *sig = task->signal;
@@ -469,7 +468,6 @@ static int do_task_stat(struct seq_file
unlock_task_sighand(task, &flags);
}
- rcu_read_unlock();
if (!whole || num_threads < 2)
wchan = get_wchan(task);
reply other threads:[~2008-02-20 17:13 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
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