Commit 06fffb12 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds
Browse files

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: default avatarOleg 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent d6cf723a

fs/proc/array.c

+0 −2
Original line number Diff line number Diff line
@@ -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);