Subject: signal: Revert ptrace preempt magic
From: Thomas Gleixner <tglx@linutronix.de>
Date: Wed Sep 21 19:57:12 2011 +0200

From: Thomas Gleixner <tglx@linutronix.de>

Upstream commit '53da1d9456fe7f8 fix ptrace slowness' is nothing more
than a bandaid around the ptrace design trainwreck. It's not a
correctness issue, it's merily a cosmetic bandaid.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>


---
 kernel/signal.c |    8 --------
 1 file changed, 8 deletions(-)
---
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2283,16 +2283,8 @@ static int ptrace_stop(int exit_code, in
 	if (gstop_done && (!current->ptrace || ptrace_reparented(current)))
 		do_notify_parent_cldstop(current, false, why);
 
-	/*
-	 * Don't want to allow preemption here, because
-	 * sys_ptrace() needs this task to be inactive.
-	 *
-	 * XXX: implement read_unlock_no_resched().
-	 */
-	preempt_disable();
 	read_unlock(&tasklist_lock);
 	cgroup_enter_frozen();
-	preempt_enable_no_resched();
 	freezable_schedule();
 	cgroup_leave_frozen(true);