* Andrew Morton <[EMAIL PROTECTED]> wrote:
> On Fri, 21 Dec 2007 00:47:59 +0100
> Ingo Molnar <[EMAIL PROTECTED]> wrote:
>
> > > __raw_spin_lock(&die.lock);
> > > raw_local_save_flags(flags);
> > > - die.lock_owner = smp_processor_id();
> > > + die.lock_owner = raw_smp_processor_id();
> >
> > we just disabled irqs with raw_local_save_flags().
>
> <chases x86 spaghetti for a while>
>
> raw_local_save_flags() doesn't disable interrupts?
argh. Indeed! (I wanted us to fix that misleading name eons ago, to
*_save_flags_only(), but some stupid bikeshed painting discussion
prevented it from ever happening.)
that should have been raw_local_irq_save(flags)!
but ... why is it done like that? Why do we first take the die.lock and
disable interrupts afterwards? It's highly weird. 64-bit does it all
correctly in traps_64.c, so unification will help us out - but so far
perhaps the patch below we should do in 2.6.24?
Ingo
------------>
Subject: x86: fix die() to not be preemptible
From: Ingo Molnar <[EMAIL PROTECTED]>
Andrew "Eagle Eye" Morton noticed that we use raw_local_save_flags()
instead of raw_local_irq_save(flags) in die().
do it correctly - and first disable interrupts, then take the spinlock.
Signed-off-by: Ingo Molnar <[EMAIL PROTECTED]>
---
arch/x86/kernel/traps_32.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
Index: linux-x86.q/arch/x86/kernel/traps_32.c
===================================================================
--- linux-x86.q.orig/arch/x86/kernel/traps_32.c
+++ linux-x86.q/arch/x86/kernel/traps_32.c
@@ -373,14 +373,13 @@ void die(const char * str, struct pt_reg
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;
--
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