x86_64: Fix to keep watchdog disabled by default for i386/x86_64

Fixed wrong expression which enabled watchdogs even if nmi_watchdog kernel
parameter wasn't set. This regression got slightly introduced with commit
b7471c6da94d30d3deadc55986cc38d1ff57f9ca.

Introduced NMI_DISABLED (-1) which allows to switch the value of NMI_DEFAULT
without breaking the APIC NMI watchdog code (again).

Fixes:
   https://bugzilla.novell.com/show_bug.cgi?id=298084
   http://bugzilla.kernel.org/show_bug.cgi?id=7839
And likely some more nmi_watchdog=0 related issues.

Signed-off-by: Daniel Gollub <dgollub@suse.de>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/arch/x86_64/kernel/nmi.c b/arch/x86_64/kernel/nmi.c
index cb8ee9d02f86..0ec6d2ddb931 100644
--- a/arch/x86_64/kernel/nmi.c
+++ b/arch/x86_64/kernel/nmi.c
@@ -85,7 +85,7 @@ int __init check_nmi_watchdog (void)
         int *counts;
         int cpu;
 
-        if ((nmi_watchdog == NMI_NONE) || (nmi_watchdog == NMI_DEFAULT))
+        if ((nmi_watchdog == NMI_NONE) || (nmi_watchdog == NMI_DISABLED)) 
                 return 0;
 
         if (!atomic_read(&nmi_active))
@@ -442,7 +442,7 @@ int proc_nmi_enabled(struct ctl_table *table, int write, struct file *file,
         if (!!old_state == !!nmi_watchdog_enabled)
                 return 0;
 
-        if (atomic_read(&nmi_active) < 0) {
+        if (atomic_read(&nmi_active) < 0 || nmi_watchdog == NMI_DISABLED) {
                 printk( KERN_WARNING "NMI watchdog is permanently disabled\n");
                 return -EIO;
         }