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

[Praveen Talari]

Hi Bjorn,

Thank you for review.

On 11/11/2025 9:38 AM, Bjorn Andersson wrote:
> 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?

Yes, that’s correct. Prasad had suggested it earlier.

Thanks,
Praveen Talari

> 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