From d3703f49c611ee0fc92b54b24df5c7195eb1d757 Mon Sep 17 00:00:00 2001
From: Andi Kleen <andi@firstfloor.org>
Date: Wed, 27 May 2009 21:56:55 +0200
Subject: [PATCH] --- yaml --- r: 148922 b: refs/heads/master c:
 f94b61c2c9fdcc90773c49df9ccf9ede3ad0d7db h: refs/heads/master v: v3

---
 [refs]                                 |  2 +-
 trunk/arch/x86/kernel/cpu/mcheck/mce.c | 22 ++++++++++++++++++++++
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index 524c45f88235..d64414686d8c 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: ccc3c3192ae78dd56dcdf5353fd1a9ef5f9a3e2b
+refs/heads/master: f94b61c2c9fdcc90773c49df9ccf9ede3ad0d7db
diff --git a/trunk/arch/x86/kernel/cpu/mcheck/mce.c b/trunk/arch/x86/kernel/cpu/mcheck/mce.c
index 121781627858..421020f1d7db 100644
--- a/trunk/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/trunk/arch/x86/kernel/cpu/mcheck/mce.c
@@ -196,10 +196,32 @@ static void print_mce(struct mce *m)
 	       "and contact your hardware vendor\n");
 }
 
+#define PANIC_TIMEOUT 5 /* 5 seconds */
+
+static atomic_t mce_paniced;
+
+/* Panic in progress. Enable interrupts and wait for final IPI */
+static void wait_for_panic(void)
+{
+	long timeout = PANIC_TIMEOUT*USEC_PER_SEC;
+	preempt_disable();
+	local_irq_enable();
+	while (timeout-- > 0)
+		udelay(1);
+	panic("Panicing machine check CPU died");
+}
+
 static void mce_panic(char *msg, struct mce *final, char *exp)
 {
 	int i;
 
+	/*
+	 * Make sure only one CPU runs in machine check panic
+	 */
+	if (atomic_add_return(1, &mce_paniced) > 1)
+		wait_for_panic();
+	barrier();
+
 	bust_spinlocks(1);
 	console_verbose();
 	/* First print corrected ones that are still unlogged */