[PATCH 3/3] kvm: ensure hard lockup detection is disabled by default

From: Andrew Jones
Date: Thu Jul 24 2014 - 06:14:12 EST

From: Ulrich Obergfell <uobergfe@xxxxxxxxxx>

Use watchdog_enable_hardlockup_detector() to set hard lockup detection's
default value to false. It's risky to run this detection in a guest, as
false positives are easy to trigger, especially if the host is

Signed-off-by: Ulrich Obergfell <uobergfe@xxxxxxxxxx>
Signed-off-by: Andrew Jones <drjones@xxxxxxxxxx>
arch/x86/kernel/kvm.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 3dd8e2c4d74a9..95c3cb16af3e5 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -35,6 +35,7 @@
#include <linux/slab.h>
#include <linux/kprobes.h>
#include <linux/debugfs.h>
+#include <linux/nmi.h>
#include <asm/timer.h>
#include <asm/cpu.h>
#include <asm/traps.h>
@@ -499,6 +500,13 @@ void __init kvm_guest_init(void)
+ /*
+ * Hard lockup detection is enabled by default. Disable it, as guests
+ * can get false positives too easily, for example if the host is
+ * overcommitted.
+ */
+ watchdog_enable_hardlockup_detector(false);

static noinline uint32_t __kvm_cpuid_base(void)

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