(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 <[email protected]>
--- 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);