Re: [PATCH v1 2/4] pinctrl: qcom: msm: Fix potential deadlock in pinmux configuration

[Bjorn Andersson]

On Mon, Nov 10, 2025 at 03:40:41PM +0530, Praveen Talari wrote:
> Replace disable_irq() with disable_irq_nosync() in msm_pinmux_set_mux()
> to prevent potential deadlock when wakeup IRQ is triggered on the same

"potential"? In what case will calling disable_irq() from the irq
handler of that irq not deadlock?

> GPIO being reconfigured.
> 
> The issue occurs when a wakeup IRQ is triggered on a GPIO and the IRQ
> handler attempts to reconfigure the same GPIO's pinmux. In this scenario,
> msm_pinmux_set_mux() calls disable_irq() which waits for the currently
> running IRQ handler to complete, creating a circular dependency that
> results in deadlock.
> 
> Using disable_irq_nosync() avoids waiting for the IRQ handler to
> complete, preventing the deadlock condition while still properly
> disabling the interrupt during pinmux reconfiguration.
> 
> Suggested-by: Prasad Sodagudi <prasad.sodagudi@xxxxxxxxxxxxxxxx>

That's weird, I debugged your deadlock for you and told you to make this
very change in:

https://lore.kernel.org/all/7sxsfyu2kqbycyfftwfhrncwk3dfnubmzhyi2rqi3jtvi5qsnh@bya3cii45zhn/

So I guess Prasad told you how to fix this issue before I invested the
time helping you?


Change looks good, and description captures the problem.

Reviewed-by: Bjorn Andersson <andersson@xxxxxxxxxx>

Regards,
Bjorn

> Signed-off-by: Praveen Talari <praveen.talari@xxxxxxxxxxxxxxxx>
> ---
>  drivers/pinctrl/qcom/pinctrl-msm.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/pinctrl/qcom/pinctrl-msm.c b/drivers/pinctrl/qcom/pinctrl-msm.c
> index 67525d542c5b..e99871b90ab9 100644
> --- a/drivers/pinctrl/qcom/pinctrl-msm.c
> +++ b/drivers/pinctrl/qcom/pinctrl-msm.c
> @@ -189,7 +189,7 @@ static int msm_pinmux_set_mux(struct pinctrl_dev *pctldev,
>  	 */
>  	if (d && i != gpio_func &&
>  	    !test_and_set_bit(d->hwirq, pctrl->disabled_for_mux))
> -		disable_irq(irq);
> +		disable_irq_nosync(irq);
>  
>  	raw_spin_lock_irqsave(&pctrl->lock, flags);
>  
> -- 
> 2.34.1
>