[PATCH] i386: don't blindly enable interrupts in die()

Rather than blindly re-enabling interrupts in die(), save their state
upon entry and then restore that state.

If the kernel is in really bad condition and faults with interrupts disabled,
re-enabling them in die() may cause even more trouble, implying more chances
of data corruption.
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

arch/i386/kernel/traps.c

@@ -306,14 +306,17 @@ void die(const char * str, struct pt_regs * regs, long err)
 		.lock_owner_depth =	0
 	};
 	static int die_counter;
+	unsigned long flags;
 
 	if (die.lock_owner != raw_smp_processor_id()) {
 		console_verbose();
-		spin_lock_irq(&die.lock);
+		spin_lock_irqsave(&die.lock, flags);
 		die.lock_owner = smp_processor_id();
 		die.lock_owner_depth = 0;
 		bust_spinlocks(1);
 	}
+	else
+		local_save_flags(flags);
 
 	if (++die.lock_owner_depth < 3) {
 		int nl = 0;
@@ -340,7 +343,7 @@ void die(const char * str, struct pt_regs * regs, long err)
 
 	bust_spinlocks(0);
 	die.lock_owner = -1;
-	spin_unlock_irq(&die.lock);
+	spin_unlock_irqrestore(&die.lock, flags);
 
 	if (kexec_should_crash(current))
 		crash_kexec(regs);