The patch titled Subject: kvm: ensure hard lockup detection is disabled by default has been added to the -mm tree. Its filename is kvm-ensure-hard-lockup-detection-is-disabled-by-default.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/kvm-ensure-hard-lockup-detection-is-disabled-by-default.patch and later at http://ozlabs.org/~akpm/mmotm/broken-out/kvm-ensure-hard-lockup-detection-is-disabled-by-default.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Ulrich Obergfell <uobergfe@xxxxxxxxxx> Subject: kvm: ensure hard lockup detection is disabled by default 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 overcommitted. Signed-off-by: Ulrich Obergfell <uobergfe@xxxxxxxxxx> Signed-off-by: Andrew Jones <drjones@xxxxxxxxxx> Signed-off-by: Don Zickus <dzickus@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/x86/kernel/kvm.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff -puN arch/x86/kernel/kvm.c~kvm-ensure-hard-lockup-detection-is-disabled-by-default arch/x86/kernel/kvm.c --- a/arch/x86/kernel/kvm.c~kvm-ensure-hard-lockup-detection-is-disabled-by-default +++ a/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) #else kvm_guest_cpu_init(); #endif + + /* + * 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) _ Patches currently in -mm which might be from uobergfe@xxxxxxxxxx are watchdog-fix-print-once-on-enable.patch watchdog-control-hard-lockup-detection-default.patch kvm-ensure-hard-lockup-detection-is-disabled-by-default.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html