From 1fdffa1f89690dc56c7da1a6b09b6d62d1d581bf Mon Sep 17 00:00:00 2001
From: "Yan, Zheng" <zheng.z.yan@intel.com>
Date: Tue, 16 Apr 2013 19:51:05 +0800
Subject: [PATCH] --- yaml --- r: 366057 b: refs/heads/master c:
 22cc4ccf63e10e361531bf61e6e6c96c53a2f665 h: refs/heads/master i:   366055:
 4604eb6b4c72b48639c7a0545d19477469011603 v: v3

---
 [refs]                                        |  2 +-
 .../x86/kernel/cpu/perf_event_intel_uncore.c  | 28 +++++++++++++++++--
 2 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/[refs] b/[refs]
index 9d4b897b44b4..b153497f2489 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 73e21ce28d8d2b75140b742b01373c3a085ecc52
+refs/heads/master: 22cc4ccf63e10e361531bf61e6e6c96c53a2f665
diff --git a/trunk/arch/x86/kernel/cpu/perf_event_intel_uncore.c b/trunk/arch/x86/kernel/cpu/perf_event_intel_uncore.c
index 75da9e18b128..50d4a1c58106 100644
--- a/trunk/arch/x86/kernel/cpu/perf_event_intel_uncore.c
+++ b/trunk/arch/x86/kernel/cpu/perf_event_intel_uncore.c
@@ -2622,6 +2622,21 @@ static void __init uncore_pci_exit(void)
 	}
 }
 
+/* CPU hot plug/unplug are serialized by cpu_add_remove_lock mutex */
+static LIST_HEAD(boxes_to_free);
+
+static void __cpuinit uncore_kfree_boxes(void)
+{
+	struct intel_uncore_box *box;
+
+	while (!list_empty(&boxes_to_free)) {
+		box = list_entry(boxes_to_free.next,
+				 struct intel_uncore_box, list);
+		list_del(&box->list);
+		kfree(box);
+	}
+}
+
 static void __cpuinit uncore_cpu_dying(int cpu)
 {
 	struct intel_uncore_type *type;
@@ -2636,7 +2651,7 @@ static void __cpuinit uncore_cpu_dying(int cpu)
 			box = *per_cpu_ptr(pmu->box, cpu);
 			*per_cpu_ptr(pmu->box, cpu) = NULL;
 			if (box && atomic_dec_and_test(&box->refcnt))
-				kfree(box);
+				list_add(&box->list, &boxes_to_free);
 		}
 	}
 }
@@ -2666,8 +2681,11 @@ static int __cpuinit uncore_cpu_starting(int cpu)
 				if (exist && exist->phys_id == phys_id) {
 					atomic_inc(&exist->refcnt);
 					*per_cpu_ptr(pmu->box, cpu) = exist;
-					kfree(box);
-					box = NULL;
+					if (box) {
+						list_add(&box->list,
+							 &boxes_to_free);
+						box = NULL;
+					}
 					break;
 				}
 			}
@@ -2806,6 +2824,10 @@ static int
 	case CPU_DYING:
 		uncore_cpu_dying(cpu);
 		break;
+	case CPU_ONLINE:
+	case CPU_DEAD:
+		uncore_kfree_boxes();
+		break;
 	default:
 		break;
 	}