Re: [patch V2 06/45] genirq/proc: Switch to lock guards

Zenghui Yu
2025-06-09T07:33:29Z

On 2025/6/8 20:45, Zenghui Yu wrote:
> Hi Thomas,
>
> On 2025/4/29 14:54, Thomas Gleixner wrote:
> > Convert all lock/unlock pairs to guards and tidy up the code.
> >
> > No functional change.
> >
> > Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> >
> > ---
> > kernel/irq/proc.c | 65 +++++++++++++++++++-----------------------------------
> > 1 file changed, 24 insertions(+), 41 deletions(-)
> >
> > --- a/kernel/irq/proc.c
> > +++ b/kernel/irq/proc.c
> > @@ -81,20 +81,18 @@ static int show_irq_affinity(int type, s
> > static int irq_affinity_hint_proc_show(struct seq_file *m, void *v)
> > {
> > struct irq_desc *desc = irq_to_desc((long)m->private);
> > - unsigned long flags;
> > cpumask_var_t mask;
> >
> > if (!zalloc_cpumask_var(&mask, GFP_KERNEL))
> > return -ENOMEM;
> >
> > - raw_spin_lock_irqsave(&desc->lock, flags);
> > - if (desc->affinity_hint)
> > - cpumask_copy(mask, desc->affinity_hint);
> > - raw_spin_unlock_irqrestore(&desc->lock, flags);
> > + scoped_guard(raw_spinlock_irq, &desc->lock) {
>
> Any reason it has been switched to a raw_spinlock_irq?
>
> I've hit some random Oops with the backtrace looks like:
>
> Call trace:
> string+0x110/0x3b8 (P)
> vsnprintf+0x2f0/0xac8
> seq_printf+0x180/0x220
> show_interrupts+0x4e0/0x7e0
> seq_read_iter+0x350/0xd80
> proc_reg_read_iter+0x194/0x248
> vfs_read+0x5b0/0x940
> ksys_read+0xf0/0x1e8
> __arm64_sys_read+0x74/0xb0
> invoke_syscall+0x74/0x270
> el0_svc_common.constprop.0+0xb4/0x240
> do_el0_svc+0x48/0x68
> el0_svc+0x4c/0xe8
> el0t_64_sync_handler+0xc8/0xd0
> el0t_64_sync+0x1ac/0x1b0
>
> I haven't dig further. But it looks to me that this patch had introduced
> functional change and I'm planning to give the following diff a go on
> the same box.
>
> Thanks,
> Zenghui
>
>>From cfad0937ffb724c2c51c8656c212ccefb09c8990 Mon Sep 17 00:00:00 2001
> From: Zenghui Yu <yuzenghui@huawei.com>
> Date: Sun, 8 Jun 2025 19:41:41 +0800
> Subject: [PATCH] fixup! genirq/proc: Switch to lock guards
>
> Signed-off-by: Zenghui Yu <yuzenghui@huawei.com>
> ---
> kernel/irq/proc.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c
> index 29c2404e743b..5af8bd1f3ab4 100644
> --- a/kernel/irq/proc.c
> +++ b/kernel/irq/proc.c
> @@ -86,7 +86,7 @@ static int irq_affinity_hint_proc_show(struct seq_file
> *m, void *v)
> if (!zalloc_cpumask_var(&mask, GFP_KERNEL))
> return -ENOMEM;
>
> - scoped_guard(raw_spinlock_irq, &desc->lock) {
> + scoped_guard(raw_spinlock_irqsave, &desc->lock) {
> if (desc->affinity_hint)
> cpumask_copy(mask, desc->affinity_hint);
> }
> @@ -298,7 +298,7 @@ static bool name_unique(unsigned int irq, struct
> irqaction *new_action)
> struct irq_desc *desc = irq_to_desc(irq);
> struct irqaction *action;
>
> - guard(raw_spinlock_irq)(&desc->lock);
> + guard(raw_spinlock_irqsave)(&desc->lock);
> for_each_action_of_desc(desc, action) {
> if ((action != new_action) && action->name &&
> !strcmp(new_action->name, action->name))
> @@ -489,7 +489,7 @@ int show_interrupts(struct seq_file *p, void *v)
> }
> seq_putc(p, ' ');
>
> - guard(raw_spinlock_irq)(&desc->lock);
> + guard(raw_spinlock_irqsave)(&desc->lock);
> if (desc->irq_data.chip) {
> if (desc->irq_data.chip->irq_print_chip)
> desc->irq_data.chip->irq_print_chip(&desc->irq_data, p);

Plus,

diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index b0e0a7332993..57facdc30d55 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -964,7 +964,7 @@ __irq_do_set_handler(struct irq_desc *desc,
irq_flow_handler_t handle,
void __irq_set_handler(unsigned int irq, irq_flow_handler_t handle, int
is_chained,
const char *name)
{
- scoped_irqdesc_get_and_lock(irq, 0)
+ scoped_irqdesc_get_and_buslock(irq, 0)
__irq_do_set_handler(scoped_irqdesc, handle, is_chained, name);
}
EXPORT_SYMBOL_GPL(__irq_set_handler);
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index c94837382037..400856abf672 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -659,7 +659,7 @@ void __disable_irq(struct irq_desc *desc)

static int __disable_irq_nosync(unsigned int irq)
{
- scoped_irqdesc_get_and_lock(irq, IRQ_GET_DESC_CHECK_GLOBAL) {
+ scoped_irqdesc_get_and_buslock(irq, IRQ_GET_DESC_CHECK_GLOBAL) {
__disable_irq(scoped_irqdesc);
return 0;
}
@@ -789,7 +789,7 @@ void __enable_irq(struct irq_desc *desc)
*/
void enable_irq(unsigned int irq)
{
- scoped_irqdesc_get_and_lock(irq, IRQ_GET_DESC_CHECK_GLOBAL) {
+ scoped_irqdesc_get_and_buslock(irq, IRQ_GET_DESC_CHECK_GLOBAL) {
struct irq_desc *desc = scoped_irqdesc;

if (WARN(!desc->irq_data.chip, "enable_irq before setup/request_irq:
irq %u\n", irq))