[PATCH] fix "NMI appears to be stuck"

  Testing NMI watchdog ... CPU#0: NMI appears to be stuck (54->54)!
  CPU#1: NMI appears to be stuck (0->0)!

Keep the PIT/HPET alive when nmi_watchdog = 1 is given on the command
line.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/i386/kernel/apic.c b/arch/i386/kernel/apic.c
index 7a2c9cbdb511ebf2150a2bf172aff45621ad5f95..2383bcf18c5d0c321712f854721441562d522025 100644 (file)
--- a/arch/i386/kernel/apic.c
+++ b/arch/i386/kernel/apic.c
@@ -493,8 +493,15 @@ void __init setup_boot_APIC_clock(void)
                /* No broadcast on UP ! */
                if (num_possible_cpus() == 1)
                        return;
-       } else
-               lapic_clockevent.features &= ~CLOCK_EVT_FEAT_DUMMY;
+       } else {
+               /*
+                * If nmi_watchdog is set to IO_APIC, we need the
+                * PIT/HPET going.  Otherwise register lapic as a dummy
+                * device.
+                */
+               if (nmi_watchdog != NMI_IO_APIC)
+                       lapic_clockevent.features &= ~CLOCK_EVT_FEAT_DUMMY;
+       }
 
        /* Setup the lapic or request the broadcast */
        setup_APIC_timer();