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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>
This commit is contained in:
Oleg Nesterov 2008-04-30 00:52:38 -07:00 committed by Linus Torvalds
parent d6cf723a14
commit 06fffb1267
1 changed files with 0 additions and 2 deletions
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2
fs/proc/array.c
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@ -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);