x86: fix die() to not be preemptible
Andrew "Eagle Eye" Morton noticed that we use raw_local_save_flags()
instead of raw_local_irq_save(flags) in die(). This allows the
preemption of oopsing contexts - which is highly undesirable. It also
causes CONFIG_DEBUG_PREEMPT to complain, as reported by Miles Lane.
this bug was introduced via:
commit 39743c9ef717fd4f2b5583f010115c5f2482b8ae
Author: Andi Kleen <ak@suse.de>
Date: Fri Oct 19 20:35:03 2007 +0200
x86: use raw locks during oopses
- spin_lock_irqsave(&die.lock, flags);
+ __raw_spin_lock(&die.lock);
+ raw_local_save_flags(flags);
that is not a correct open-coding of spin_lock_irqsave(): both the
ordering is wrong (irqs should be disabled _first_), and the wrong
flags-saving API was used.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/kernel/traps_32.c b/arch/x86/kernel/traps_32.c
index ef60102..c88bbff 100644
--- a/arch/x86/kernel/traps_32.c
+++ b/arch/x86/kernel/traps_32.c
@@ -373,14 +373,13 @@
if (die.lock_owner != raw_smp_processor_id()) {
console_verbose();
+ raw_local_irq_save(flags);
__raw_spin_lock(&die.lock);
- raw_local_save_flags(flags);
die.lock_owner = smp_processor_id();
die.lock_owner_depth = 0;
bust_spinlocks(1);
- }
- else
- raw_local_save_flags(flags);
+ } else
+ raw_local_irq_save(flags);
if (++die.lock_owner_depth < 3) {
unsigned long esp;