linux-kernel - [PATCH] [10/28] x86: MCE: Remove oops_begin() use in 64bit machine check

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Message-Id: <20090407150751.841D91D046E@basil.firstfloor.org>
Date:	Tue,  7 Apr 2009 17:07:51 +0200 (CEST)
From:	Andi Kleen <andi@...stfloor.org>
To:	hpa@...or.com, linux-kernel@...r.kernel.org, mingo@...e.hu,
	tglx@...utronix.de
Subject: [PATCH] [10/28] x86: MCE: Remove oops_begin() use in 64bit machine check


On closer examination it turns out oops_begin is not 
a good idea in a machine check panic. All oops_begin
does it so check for recursive/parallel oopses and implement the
"wait on oops" heuristic. But there's actually no good reason
to lock machine checks against oopses or prevent them
from recursion. Also "wait on oops" does not really make
sense for a machine check either.

So just remove it.

Replace it with a manual bust_spinlocks/console_verbose.

Signed-off-by: Andi Kleen <ak@...ux.intel.com>

---
 arch/x86/kernel/cpu/mcheck/mce_64.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Index: linux/arch/x86/kernel/cpu/mcheck/mce_64.c
===================================================================
--- linux.orig/arch/x86/kernel/cpu/mcheck/mce_64.c	2009-04-07 16:09:59.000000000 +0200
+++ linux/arch/x86/kernel/cpu/mcheck/mce_64.c	2009-04-07 16:43:13.000000000 +0200
@@ -151,7 +151,8 @@
 {
 	int i;
 
-	oops_begin();
+	bust_spinlocks(1);
+	console_verbose();
 	for (i = 0; i < MCE_LOG_LEN; i++) {
 		unsigned long tsc = mcelog.entry[i].tsc;
 
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