[PATCH 1/1] i386: fix a hang on stuck nmi watchdog

From: Daniel Walker
Date: Sat Sep 01 2007 - 17:00:29 EST


In the case when an nmi gets stucks the endflag stays equal to zero. This
causes the busy looping on other cpus to continue, even tho the nmi test
is done.

On my machine with out the change below the system would hang right after
check_nmi_watchdog(). The change below just sets endflag prior to checking
if the test was successful or not.

Signed-off-by: Daniel Walker <dwalker@xxxxxxxxxx>

---
arch/i386/kernel/nmi.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux-2.6.22/arch/i386/kernel/nmi.c
===================================================================
--- linux-2.6.22.orig/arch/i386/kernel/nmi.c
+++ linux-2.6.22/arch/i386/kernel/nmi.c
@@ -115,12 +115,12 @@ static int __init check_nmi_watchdog(voi
atomic_dec(&nmi_active);
}
}
+ endflag = 1;
if (!atomic_read(&nmi_active)) {
kfree(prev_nmi_count);
atomic_set(&nmi_active, -1);
return -1;
}
- endflag = 1;
printk("OK.\n");

/* now that we know it works we can reduce NMI frequency to
--

--
-
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