[PATCH] Fix up panic messages for different NMI panics

When a unknown NMI happened the panic would claim a NMI watchdog timeout.
Also it would check the variable set by nmi_watchdog=panic and panic then.

Fix up the panic message to be generic
Unconditionally panic on unknown NMI when panic on unknown nmi is enabled.

Noticed by Jan Beulich

Cc: jbeulich@novell.com

Signed-off-by: Andi Kleen <ak@suse.de>

arch/x86_64/kernel/nmi.c

@@ -695,7 +695,8 @@ int __kprobes nmi_watchdog_tick(struct pt_regs * regs, unsigned reason)
 		 */
 		local_inc(&__get_cpu_var(alert_counter));
 		if (local_read(&__get_cpu_var(alert_counter)) == 5*nmi_hz)
-			die_nmi("NMI Watchdog detected LOCKUP on CPU %d\n", regs);
+			die_nmi("NMI Watchdog detected LOCKUP on CPU %d\n", regs,
+				panic_on_timeout);
 	} else {
 		__get_cpu_var(last_irq_sum) = sum;
 		local_set(&__get_cpu_var(alert_counter), 0);
@@ -765,7 +766,7 @@ static int unknown_nmi_panic_callback(struct pt_regs *regs, int cpu)
 	char buf[64];
 
 	sprintf(buf, "NMI received for unknown reason %02x\n", reason);
-	die_nmi(buf,regs);
+	die_nmi(buf, regs, 1);	/* Always panic here */
 	return 0;
 }
 

arch/x86_64/kernel/traps.c

@@ -570,7 +570,7 @@ void die(const char * str, struct pt_regs * regs, long err)
 	do_exit(SIGSEGV); 
 }
 
-void __kprobes die_nmi(char *str, struct pt_regs *regs)
+void __kprobes die_nmi(char *str, struct pt_regs *regs, int do_panic)
 {
 	unsigned long flags = oops_begin();
 
@@ -582,9 +582,8 @@ void __kprobes die_nmi(char *str, struct pt_regs *regs)
 	show_registers(regs);
 	if (kexec_should_crash(current))
 		crash_kexec(regs);
-	if (panic_on_timeout || panic_on_oops)
-		panic("nmi watchdog");
-	printk("console shuts up ...\n");
+	if (do_panic || panic_on_oops)
+		panic("Non maskable interrupt");
 	oops_end(flags);
 	nmi_exit();
 	local_irq_enable();

include/asm-x86_64/nmi.h

@@ -37,7 +37,7 @@ static inline void unset_nmi_pm_callback(struct pm_dev * dev)
 #endif /* CONFIG_PM */
  
 extern void default_do_nmi(struct pt_regs *);
-extern void die_nmi(char *str, struct pt_regs *regs);
+extern void die_nmi(char *str, struct pt_regs *regs, int do_panic);
 
 #define get_nmi_reason() inb(0x61)