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From 2f49ee1bd94717b5c7f07bbc14b5a452b2cf47f2 Mon Sep 17 00:00:00 2001
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From: Dave Jones <davej@redhat.com>
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Date: Tue, 24 Jun 2014 08:43:34 -0400
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Subject: [PATCH] watchdog: Disable watchdog on virtual machines.
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For various reasons, VMs seem to trigger the soft lockup detector a lot,
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in cases where it's just not possible for a lockup to occur.
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(Example: https://bugzilla.redhat.com/show_bug.cgi?id=971139)
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In some cases it seems that the host just never scheduled the app running
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the VM for a very long time (Could be the host was under heavy load).
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Just disable the detector on VMs.
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Bugzilla: 971139
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Upstream-status: Fedora mustard for now
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Signed-off-by: Dave Jones <davej@redhat.com>
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---
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 kernel/watchdog.c | 29 +++++++++++++++++++++++++++++
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 1 file changed, 29 insertions(+)
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diff --git a/kernel/watchdog.c b/kernel/watchdog.c
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index a8d6914030fe..d0a8c308170d 100644
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--- a/kernel/watchdog.c
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+++ b/kernel/watchdog.c
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@@ -24,6 +24,7 @@
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 #include <linux/sysctl.h>
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 #include <linux/smpboot.h>
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 #include <linux/sched/rt.h>
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+#include <linux/dmi.h>
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 #include <asm/irq_regs.h>
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 #include <linux/kvm_para.h>
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@@ -112,6 +113,32 @@ static int __init softlockup_all_cpu_backtrace_setup(char *str)
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 __setup("softlockup_all_cpu_backtrace=", softlockup_all_cpu_backtrace_setup);
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 #endif
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+static int disable_watchdog(const struct dmi_system_id *d)
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+{
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+	printk(KERN_INFO "watchdog: disabled (inside virtual machine)\n");
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+	watchdog_user_enabled = 0;
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+	return 0;
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+}
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+
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+static const struct dmi_system_id watchdog_virt_dmi_table[] = {
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+	{
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+		.callback = disable_watchdog,
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+		.ident = "VMware",
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+		.matches = {
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+			DMI_MATCH(DMI_SYS_VENDOR, "VMware, Inc."),
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+		},
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+	},
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+	{
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+		.callback = disable_watchdog,
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+		.ident = "Bochs",
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+		.matches = {
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+			DMI_MATCH(DMI_SYS_VENDOR, "Bochs"),
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+		},
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+	},
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+	{}
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+};
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+
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+
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 /*
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  * Hard-lockup warnings should be triggered after just a few seconds. Soft-
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  * lockups can have false positives under extreme conditions. So we generally
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@@ -644,6 +671,8 @@ out:
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 void __init lockup_detector_init(void)
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 {
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+	dmi_check_system(watchdog_virt_dmi_table);
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+
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 	set_sample_period();
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 	if (watchdog_user_enabled)
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-- 
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1.9.3
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