From 643b982c4f1aac840fa7ddbecac0c6bb0cc156bc Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
Date: Fri, 19 Nov 2010 20:37:53 +0100
Subject: [PATCH] --- yaml --- r: 223999 b: refs/heads/master c:
 51a96c77815e7f139892a6e9c8275a50e9baebdf h: refs/heads/master i:   223997:
 10868aafdb37454fe670afa261d8252de0e322e7   223995:
 cd03ad3016ebe2e37419e2fb238cfc4df9c76462   223991:
 0d93270f77dbaea03feb05a581f7f7f79e3174da   223983:
 4c2204d2d9907bfd7029c5bdc4d6fcb9622bff1c   223967:
 32f3822db22fd0ae37f299e18226398884c002be   223935:
 739b857adf5f1be1b273c247bf4e809265979017   223871:
 91249362cfbe20e49aa35b514d8250e578df1144   223743:
 63afd0d8de012fe33e9b9bfe9a7264d17a5abe23 v: v3

---
 [refs]             | 2 +-
 trunk/kernel/cpu.c | 5 ++++-
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/[refs] b/[refs]
index 1dc10d1e9e2f..3071d435b3ca 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 2e01f4740a874b6085da6ebf541e7ffde9a72bf2
+refs/heads/master: 51a96c77815e7f139892a6e9c8275a50e9baebdf
diff --git a/trunk/kernel/cpu.c b/trunk/kernel/cpu.c
index 3945066fc01d..cb7a1efa9c2b 100644
--- a/trunk/kernel/cpu.c
+++ b/trunk/kernel/cpu.c
@@ -249,8 +249,11 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
 	 * The migration_call() CPU_DYING callback will have removed all
 	 * runnable tasks from the cpu, there's only the idle task left now
 	 * that the migration thread is done doing the stop_machine thing.
+	 *
+	 * Wait for the stop thread to go away.
 	 */
-	BUG_ON(!idle_cpu(cpu));
+	while (!idle_cpu(cpu))
+		cpu_relax();
 
 	/* This actually kills the CPU. */
 	__cpu_die(cpu);