On Mon, Jul 24, 2017 at 04:32:42PM -0500, Scott Wood wrote:
> register_nmi_handler() can be called from PREEMPT_RT atomic context
> (e.g. wakeup_cpu_via_init_nmi() or native_stop_other_cpus()), and thus
> ordinary spinlocks cannot be used.
Yeah, I guess we have a few awkward places where we register an nmi handler.
Acked-by: Don Zickus <dzic...@redhat.com>
>
> Signed-off-by: Scott Wood <sw...@redhat.com>
> ---
> arch/x86/kernel/nmi.c | 18 +++++++++---------
> 1 file changed, 9 insertions(+), 9 deletions(-)
>
> diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c
> index 446c8aa09b9b..35aafc95e4b8 100644
> --- a/arch/x86/kernel/nmi.c
> +++ b/arch/x86/kernel/nmi.c
> @@ -39,26 +39,26 @@
> #include <trace/events/nmi.h>
>
> struct nmi_desc {
> - spinlock_t lock;
> + raw_spinlock_t lock;
> struct list_head head;
> };
>
> static struct nmi_desc nmi_desc[NMI_MAX] =
> {
> {
> - .lock = __SPIN_LOCK_UNLOCKED(&nmi_desc[0].lock),
> + .lock = __RAW_SPIN_LOCK_UNLOCKED(&nmi_desc[0].lock),
> .head = LIST_HEAD_INIT(nmi_desc[0].head),
> },
> {
> - .lock = __SPIN_LOCK_UNLOCKED(&nmi_desc[1].lock),
> + .lock = __RAW_SPIN_LOCK_UNLOCKED(&nmi_desc[1].lock),
> .head = LIST_HEAD_INIT(nmi_desc[1].head),
> },
> {
> - .lock = __SPIN_LOCK_UNLOCKED(&nmi_desc[2].lock),
> + .lock = __RAW_SPIN_LOCK_UNLOCKED(&nmi_desc[2].lock),
> .head = LIST_HEAD_INIT(nmi_desc[2].head),
> },
> {
> - .lock = __SPIN_LOCK_UNLOCKED(&nmi_desc[3].lock),
> + .lock = __RAW_SPIN_LOCK_UNLOCKED(&nmi_desc[3].lock),
> .head = LIST_HEAD_INIT(nmi_desc[3].head),
> },
>
> @@ -163,7 +163,7 @@ int __register_nmi_handler(unsigned int type, struct
> nmiaction *action)
>
> init_irq_work(&action->irq_work, nmi_max_handler);
>
> - spin_lock_irqsave(&desc->lock, flags);
> + raw_spin_lock_irqsave(&desc->lock, flags);
>
> /*
> * Indicate if there are multiple registrations on the
> @@ -181,7 +181,7 @@ int __register_nmi_handler(unsigned int type, struct
> nmiaction *action)
> else
> list_add_tail_rcu(&action->list, &desc->head);
>
> - spin_unlock_irqrestore(&desc->lock, flags);
> + raw_spin_unlock_irqrestore(&desc->lock, flags);
> return 0;
> }
> EXPORT_SYMBOL(__register_nmi_handler);
> @@ -192,7 +192,7 @@ void unregister_nmi_handler(unsigned int type, const char
> *name)
> struct nmiaction *n;
> unsigned long flags;
>
> - spin_lock_irqsave(&desc->lock, flags);
> + raw_spin_lock_irqsave(&desc->lock, flags);
>
> list_for_each_entry_rcu(n, &desc->head, list) {
> /*
> @@ -207,7 +207,7 @@ void unregister_nmi_handler(unsigned int type, const char
> *name)
> }
> }
>
> - spin_unlock_irqrestore(&desc->lock, flags);
> + raw_spin_unlock_irqrestore(&desc->lock, flags);
> synchronize_rcu();
> }
> EXPORT_SYMBOL_GPL(unregister_nmi_handler);
> --
> 1.8.3.1
>
