locking-selftest-add-RT-workarounds.patch

From b04af1be28e4f489dbf8dec6069e028af1dc1224 Mon Sep 17 00:00:00 2001
From: Paul Gortmaker <paul.gortmaker@windriver.com>
Date: Sun, 16 Jan 2011 15:37:33 -0500
Subject: [PATCH] locking selftest: add RT workarounds.

In RT space, there are some hoops to jump through to avoid warnings
at boot.

This is one of several extractions from the merge up to 33-rc8.

You can find the origin of this change in the tip merge commit:

     commit 5f854cfc024622e4aae14d7cf422f6ff86278688
     Merge: cc24da0 4ec62b2
     Author: Thomas Gleixner <tglx@linutronix.de>
     Date:   Sun Feb 21 20:17:22 2010 +0100

         Forward to 2.6.33-rc8

         Merge branch 'linus' into rt/head with a pile of conflicts.

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

Normally there are not significant changes/additions in a merge commit that
are not from any other "normal" commit.  But in this case there are, so
break them out into separate explicit commits.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/init/main.c b/init/main.c
index 4445c08..8f95889 100644
--- a/init/main.c
+++ b/init/main.c
@@ -623,7 +623,16 @@ asmlinkage void __init start_kernel(void)
 	 * to self-test [hard/soft]-irqs on/off lock inversion bugs
 	 * too:
 	 */
-	locking_selftest();
+	if (1) {
+		/*
+		 * Hack around the fact that locking_selftest() destroys
+		 * the lockdep state, so release the one known lock and
+		 * acquire it again after the self-test is done.
+		 */
+		mutex_release(&kernel_sem.dep_map, 1, _THIS_IP_);
+		locking_selftest();
+		mutex_acquire(&kernel_sem.dep_map, 0, 0, _THIS_IP_);
+	}
 
 #ifdef CONFIG_BLK_DEV_INITRD
 	if (initrd_start && !initrd_below_start_ok &&
-- 
1.7.1.1