[PATCH] start_kernel: test if irq's got enabled early, barf, and disable them again
Ard van Breemen [Sat, 6 Jan 2007 00:36:19 +0000 (16:36 -0800)]
The calls made by parse_parms to other initialization code might enable
interrupts again way too early.

Having interrupts on this early can make systems PANIC when they initialize
the IRQ controllers (which happens later in the code).  This patch detects
that irq's are enabled again, barfs about it and disables them again as a
safety net.

[akpm@osdl.org: cleanups]
Signed-off-by: Ard van Breemen <ard@telegraafnet.nl>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

init/main.c

index 2b1cdaa..bc27d72 100644 (file)
@@ -538,6 +538,11 @@ asmlinkage void __init start_kernel(void)
        parse_args("Booting kernel", command_line, __start___param,
                   __stop___param - __start___param,
                   &unknown_bootoption);
+       if (!irqs_disabled()) {
+               printk(KERN_WARNING "start_kernel(): bug: interrupts were "
+                               "enabled *very* early, fixing it\n");
+               local_irq_disable();
+       }
        sort_main_extable();
        trap_init();
        rcu_init();