[PATCH -tip] kgdb, x86: Pull up NMI notifier handler priority

[Cyrill Gorcunov]

kgdb needs IPI to be sent and handled before perf
or anything else NMI, otherwise kgdb hangs with bootup
self-tests (found on P4 HT SMP machine). Raise its priority
so that we're called first in a notifier chain.

Reported-by: Don Zickus <dzickus@xxxxxxxxxx>
Tested-by: Lin Ming <ming.m.lin@xxxxxxxxx>
CC: Jason Wessel <jason.wessel@xxxxxxxxxxxxx>
Signed-off-by: Cyrill Gorcunov <gorcunov@xxxxxxxxxx>
---

Don, Jason, take a look please.

 arch/x86/kernel/kgdb.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

Index: linux-2.6.git/arch/x86/kernel/kgdb.c
=====================================================================
--- linux-2.6.git.orig/arch/x86/kernel/kgdb.c
+++ linux-2.6.git/arch/x86/kernel/kgdb.c
@@ -592,9 +592,12 @@ static struct notifier_block kgdb_notifi
 	.notifier_call	= kgdb_notify,

 	/*
-	 * Lowest-prio notifier priority, we want to be notified last:
+	 * We might need to send an IPI and
+	 * do cpu roundup before anything else
+	 * in notifier chain so high priority
+	 * is needed.
 	 */
-	.priority	= NMI_LOCAL_LOW_PRIOR,
+	.priority	= NMI_LOCAL_HIGH_PRIOR,
 };

 /**

-- 
    Cyrill
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