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

Zenghui Yu
2025-06-08T12:45:54Z

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);
--
2.33.0