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authorDave Jones <davej@redhat.com>2013-06-11 16:36:11 -0400
committerDave Jones <davej@redhat.com>2013-06-11 16:36:11 -0400
commit18e50ce8f8d390b47ed295bbe96566c6bccf7e6f (patch)
tree61cc9f9062d2fecff45ea574dd85a8d545e00976 /nowatchdog-on-virt.patch
parentd08f67e2b7e48a4065b37bc9b1e3bf7a5a056d55 (diff)
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Disable soft lockup detector on virtual machines. (rhbz 971139)
Diffstat (limited to 'nowatchdog-on-virt.patch')
-rw-r--r--nowatchdog-on-virt.patch67
1 files changed, 67 insertions, 0 deletions
diff --git a/nowatchdog-on-virt.patch b/nowatchdog-on-virt.patch
new file mode 100644
index 000000000..b20642204
--- /dev/null
+++ b/nowatchdog-on-virt.patch
@@ -0,0 +1,67 @@
+Disable watchdog on virtual machines.
+
+For various reasons, VMs seem to trigger the soft lockup detector a lot,
+in cases where it's just not possible for a lockup to occur.
+(Example: https://bugzilla.redhat.com/show_bug.cgi?id=971139)
+
+In some cases it seems that the host just never scheduled the app running
+the VM for a very long time (Could be the host was under heavy load).
+
+Just disable the detector on VMs.
+
+Signed-off-by: Dave Jones <davej@redhat.com>
+
+diff --git a/kernel/watchdog.c b/kernel/watchdog.c
+index 05039e3..a28aab9 100644
+--- a/kernel/watchdog.c
++++ b/kernel/watchdog.c
+@@ -24,6 +24,7 @@
+ #include <linux/sysctl.h>
+ #include <linux/smpboot.h>
+ #include <linux/sched/rt.h>
++#include <linux/dmi.h>
+
+ #include <asm/irq_regs.h>
+ #include <linux/kvm_para.h>
+@@ -96,6 +97,32 @@ static int __init nosoftlockup_setup(char *str)
+ __setup("nosoftlockup", nosoftlockup_setup);
+ /* */
+
++static int disable_watchdog(const struct dmi_system_id *d)
++{
++ printk(KERN_INFO "watchdog: disabled (inside virtual machine)\n");
++ watchdog_enabled = 0;
++ return 0;
++}
++
++static const struct dmi_system_id watchdog_virt_dmi_table[] = {
++ {
++ .callback = disable_watchdog,
++ .ident = "VMware",
++ .matches = {
++ DMI_MATCH(DMI_SYS_VENDOR, "VMware, Inc."),
++ },
++ },
++ {
++ .callback = disable_watchdog,
++ .ident = "Bochs",
++ .matches = {
++ DMI_MATCH(DMI_SYS_VENDOR, "Bochs Bochs"),
++ },
++ },
++ {}
++};
++
++
+ /*
+ * Hard-lockup warnings should be triggered after just a few seconds. Soft-
+ * lockups can have false positives under extreme conditions. So we generally
+@@ -543,6 +570,8 @@ static struct smp_hotplug_thread watchdog_threads = {
+
+ void __init lockup_detector_init(void)
+ {
++ dmi_check_system(watchdog_virt_dmi_table);
++
+ set_sample_period();
+ if (smpboot_register_percpu_thread(&watchdog_threads)) {
+ pr_err("Failed to create watchdog threads, disabled\n");