Re: [PATCH v3 3/8] irqchip/qcom-pdc: Remove pdc_enable_intr() wrapper

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] Uninitialized spinlock acquired during driver probe.
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commit ff89675171bbba82a63beea5300191b24d1a290f
Author: Maulik Shah <maulik.shah@oss.qualcomm.com>

irqchip/qcom-pdc: Remove pdc_enable_intr() wrapper

This commit removes the pdc_enable_intr() wrapper and moves its locking
into pdc_enable_intr_bank(), as the lock is only needed for the shared
bank and not for individual IRQ_CFG registers.

> diff --git a/drivers/irqchip/qcom-pdc.c b/drivers/irqchip/qcom-pdc.c
> index b9acb0f25c9c8..6c556464d37c0 100644
> --- a/drivers/irqchip/qcom-pdc.c
> +++ b/drivers/irqchip/qcom-pdc.c
> @@ -206,6 +206,8 @@ static void pdc_enable_intr_bank(int pin_out, bool on)
>  	index = FIELD_GET(IRQ_ENABLE_BANK_INDEX_MASK, pin_out);
>  	mask = FIELD_GET(IRQ_ENABLE_BANK_BIT_MASK, pin_out);
>  
> +	guard(raw_spinlock)(&pdc->lock);

[Severity: High]
Does this cause an uninitialized spinlock to be acquired during driver probe?

Looking at qcom_pdc_probe(), the lock is initialized after setting up the pin
mapping:

qcom_pdc_probe() {
    ...
    ret = pdc_setup_pin_mapping(dev, node);
    ...
    raw_spin_lock_init(&pdc->lock);
    ...
}

And pdc_setup_pin_mapping() invokes pdc->enable_intr() for each pin:

pdc_setup_pin_mapping() {
    ...
    for (int i = 0; i < pdc->region[n].cnt; i++)
        pdc->enable_intr(i + pdc->region[n].pin_base, 0);
    ...
}

Previously, pdc_setup_pin_mapping() bypassed the lock because it was held in
the pdc_enable_intr() wrapper, not the enable_intr() callback. By moving the
lock down into pdc_enable_intr_bank(), won't the probe sequence now attempt to
acquire a zero-initialized lock before it has been initialized with
raw_spin_lock_init()?

> +
>  	enable = pdc_reg_read(pdc->regs->irq_en_reg, index);
>  	__assign_bit(mask, &enable, on);
>  
[ ... ]

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260616-hamoa_pdc_v3-v3-0-4d8e1504ea75@oss.qualcomm.com?part=3