From 06fffb1267c9d986687b69d74a46ee332a50575e Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@tv-sign.ru>
Date: Wed, 30 Apr 2008 00:52:38 -0700
Subject: [PATCH] do_task_stat: don't take rcu_read_lock()
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>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Pavel Emelyanov <xemul@sw.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
fs/proc/array.c | 2 --
1 file changed, 2 deletions(-)
diff --git a/fs/proc/array.c b/fs/proc/array.c
index 07d6c4853fe8..b07a71002f2f 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -425,7 +425,6 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
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 *m, struct pid_namespace *ns,
unlock_task_sighand(task, &flags);
}
- rcu_read_unlock();
if (!whole || num_threads < 2)
wchan = get_wchan(task);
--
2.20.1