From 6f82e0f9ec3f72c67a49548c040b98a8639db827 Mon Sep 17 00:00:00 2001
From: Kevin Cernekee <cernekee@gmail.com>
Date: Thu, 3 Jun 2010 22:11:25 -0700
Subject: [PATCH] --- yaml --- r: 204525 b: refs/heads/master c:
 034260d6779087431a8b2f67589c68b919299e5c h: refs/heads/master i:   204523:
 4ced5332a4bafb1b8cee3dea97257ef82530e52f v: v3

---
 [refs]                |  2 +-
 trunk/kernel/printk.c | 33 +++++++++++++++++++++++++++++++--
 2 files changed, 32 insertions(+), 3 deletions(-)

diff --git a/[refs] b/[refs]
index 889a3742c061..bb11478affa9 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: d745866e4d8c0675bab90868b5e4a8fcd053eff2
+refs/heads/master: 034260d6779087431a8b2f67589c68b919299e5c
diff --git a/trunk/kernel/printk.c b/trunk/kernel/printk.c
index 444b770c9595..4ab0164bcf84 100644
--- a/trunk/kernel/printk.c
+++ b/trunk/kernel/printk.c
@@ -37,6 +37,8 @@
 #include <linux/ratelimit.h>
 #include <linux/kmsg_dump.h>
 #include <linux/syslog.h>
+#include <linux/cpu.h>
+#include <linux/notifier.h>
 
 #include <asm/uaccess.h>
 
@@ -984,6 +986,32 @@ void resume_console(void)
 	release_console_sem();
 }
 
+/**
+ * console_cpu_notify - print deferred console messages after CPU hotplug
+ * @self: notifier struct
+ * @action: CPU hotplug event
+ * @hcpu: unused
+ *
+ * If printk() is called from a CPU that is not online yet, the messages
+ * will be spooled but will not show up on the console.  This function is
+ * called when a new CPU comes online (or fails to come up), and ensures
+ * that any such output gets printed.
+ */
+static int __cpuinit console_cpu_notify(struct notifier_block *self,
+	unsigned long action, void *hcpu)
+{
+	switch (action) {
+	case CPU_ONLINE:
+	case CPU_DEAD:
+	case CPU_DYING:
+	case CPU_DOWN_FAILED:
+	case CPU_UP_CANCELED:
+		acquire_console_sem();
+		release_console_sem();
+	}
+	return NOTIFY_OK;
+}
+
 /**
  * acquire_console_sem - lock the console system for exclusive use.
  *
@@ -1371,7 +1399,7 @@ int unregister_console(struct console *console)
 }
 EXPORT_SYMBOL(unregister_console);
 
-static int __init disable_boot_consoles(void)
+static int __init printk_late_init(void)
 {
 	struct console *con;
 
@@ -1382,9 +1410,10 @@ static int __init disable_boot_consoles(void)
 			unregister_console(con);
 		}
 	}
+	hotcpu_notifier(console_cpu_notify, 0);
 	return 0;
 }
-late_initcall(disable_boot_consoles);
+late_initcall(printk_late_init);
 
 #if defined CONFIG_PRINTK