From 6ecafa8ec329a7891d96a0cc5a9091cf69491ea6 Mon Sep 17 00:00:00 2001
From: Ingo Molnar <mingo@elte.hu>
Date: Fri, 3 Jul 2009 08:30:32 -0500
Subject: [PATCH] trace: disable workqueue tracer on RT

commit 9026677c72e1f3c1682ccd461d80f9467f13b8e4 in tip.

Turn it off for now:

BUG: sleeping function called from invalid context at kernel/rtmutex.c:683
in_atomic(): 1, irqs_disabled(): 0, pid: 1, name: init
1 lock held by init/1:
 #0:  (&cwq->lock){--..}, at: [<ffffffff8025e6f1>] __queue_work+0x21/0x50
Pid: 1, comm: init Not tainted 2.6.29-rc4-rt0-tip #186
Call Trace:
 [<ffffffff802765d3>] ? __debug_show_held_locks+0x13/0x30
 [<ffffffff80238fc1>] __might_sleep+0x141/0x180
 [<ffffffff805c0c26>] __lock_text_start+0x56/0xd0
 [<ffffffff8020c6d6>] ? ftrace_call+0x5/0x2b
 [<ffffffff802aabd8>] probe_workqueue_insertion+0x18/0xc0
 [<ffffffff8025e197>] insert_work+0x87/0x190
 [<ffffffff8025e703>] __queue_work+0x33/0x50
 [<ffffffff8025e84f>] queue_work_on+0xaf/0xc0
 [<ffffffff8025e896>] queue_work+0x16/0x20
 [<ffffffff8025db2f>] call_usermodehelper_exec+0xff/0x130
 [<ffffffff8026ccfc>] ? prepare_usermodehelper_creds+0x15c/0x180
 [<ffffffff8026ccfc>] ? prepare_usermodehelper_creds+0x15c/0x180
 [<ffffffff803af071>] kobject_uevent_env+0x8f1/0x900
 [<ffffffff8020c6d6>] ? ftrace_call+0x5/0x2b
 [<ffffffff803af08b>] kobject_uevent+0xb/0x10
 [<ffffffff8040f373>] device_add+0x793/0xa70
 [<ffffffff8040f66e>] device_register+0x1e/0x30
 [<ffffffff8040f8de>] device_create_vargs+0x13e/0x180
 [<ffffffff8040f951>] device_create+0x31/0x40
 [<ffffffff8020c6d6>] ? ftrace_call+0x5/0x2b
 [<ffffffff803eb30b>] vcs_make_sysfs+0x3b/0x70
 [<ffffffff803f4e18>] con_open+0x128/0x160
 [<ffffffff803dda5d>] tty_open+0x2fd/0x7a0
 [<ffffffff802ef8f5>] chrdev_open+0x185/0x230
 [<ffffffff802ef770>] ? chrdev_open+0x0/0x230
 [<ffffffff802e823f>] __dentry_open+0x1ff/0x4c0
 [<ffffffff802e862c>] nameidata_to_filp+0x4c/0x80
 [<ffffffff802fc86e>] do_filp_open+0x39e/0xd20
 [<ffffffff805c2aa4>] ? __spin_unlock_irqrestore+0x74/0xb0
 [<ffffffff805bf8da>] ? rt_spin_lock_slowunlock+0x5a/0xa0
 [<ffffffff8030bab4>] ? alloc_fd+0xa4/0x1e0
 [<ffffffff802e7f43>] do_sys_open+0xd3/0x160
 [<ffffffff802e8010>] sys_open+0x20/0x30
 [<ffffffff8020ca48>] system_call_fastpath+0x16/0x1b

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 60e2ce0..6929bc7 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -412,7 +412,7 @@ config KMEMTRACE
 	  If unsure, say N.
 
 config WORKQUEUE_TRACER
-	bool "Trace workqueues"
+	bool "Trace workqueues" if !PREEMPT_RT
 	select GENERIC_TRACER
 	help
 	  The workqueue tracer provides some statistical information
-- 
1.7.1.1