Re: [PATCH 1/6] iio: adc: versal-sysmon: fix race in interrupt teardown

[Prasanna Kumar T S M <ptsm@linux.microsoft.com>]

Hi Amit,

On 02-11-2026 17:51, Amit Kumar Mahapatra wrote:
> sysmon_disable_interrupts() masks all interrupts, clears masked_temp and
> cancels the unmask worker, but leaves the interrupt handler live. A
> worker that is already running can re-enable an alarm through IER after
> the mask write. If that alarm fires, the handler queues the worker again
> after cancel_delayed_work_sync() has returned. On unbind this action runs
> before devm releases the IRQ, so the queued work can run after the
> devm-allocated iio_dev that embeds it has been freed.
> 
> Disable the IRQ first so that no handler is running or can start, then
> clear masked_temp and cancel the worker, and mask all interrupts last,
> once nothing is left that can unmask them. Record the IRQ number for
> this.
> 
> Fixes: c7f7eb10638f ("iio: adc: versal-sysmon: add threshold event support")
> Signed-off-by: Amit Kumar Mahapatra <amit.kumar-mahapatra@amd.com>
> ---
>   drivers/iio/adc/versal-sysmon-core.c | 5 ++++-
>   drivers/iio/adc/versal-sysmon.h      | 2 ++
>   2 files changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iio/adc/versal-sysmon-core.c b/drivers/iio/adc/versal-sysmon-core.c
> index 1b55d343982e..6b9a58e19831 100644
> --- a/drivers/iio/adc/versal-sysmon-core.c
> +++ b/drivers/iio/adc/versal-sysmon-core.c
> @@ -781,12 +781,14 @@ static void sysmon_disable_interrupts(void *data)
>   {
>   	struct sysmon *sysmon = data;
>   
> -	regmap_write(sysmon->regmap, SYSMON_IDR, SYSMON_INTR_ALL_MASK);
> +	disable_irq(sysmon->irq);
>   
>   	scoped_guard(spinlock_irq, &sysmon->irq_lock)
>   		sysmon->masked_temp = 0;
>   
>   	cancel_delayed_work_sync(&sysmon->sysmon_unmask_work);
> +
> +	regmap_write(sysmon->regmap, SYSMON_IDR, SYSMON_INTR_ALL_MASK);
>   }
>   
>   static int sysmon_init_interrupt(struct sysmon *sysmon,
> @@ -807,6 +809,7 @@ static int sysmon_init_interrupt(struct sysmon *sysmon,
>   	if (ret)
>   		return ret;
>   	sysmon->temp_mask = imr & SYSMON_TEMP_INTR_MASK;
> +	sysmon->irq = irq;
>   
>   	ret = devm_request_irq(dev, irq, sysmon_iio_irq, 0, "sysmon-irq", indio_dev);
>   	if (ret)
> diff --git a/drivers/iio/adc/versal-sysmon.h b/drivers/iio/adc/versal-sysmon.h
> index bb9a75bf71c0..701ef9b56263 100644
> --- a/drivers/iio/adc/versal-sysmon.h
> +++ b/drivers/iio/adc/versal-sysmon.h
> @@ -85,6 +85,7 @@ struct regmap;
>    * @regmap: register map for hardware access
>    * @lock: protects read-modify-write sequences on threshold registers
>    *        and cached state that spans multiple regmap calls
> + * @irq: interrupt number, 0 when events are not supported
>    * @irq_lock: protects interrupt mask register updates (MMIO path only)
>    * @masked_temp: currently masked temperature alarm bits
>    * @temp_mask: temperature interrupt configuration mask
> @@ -101,6 +102,7 @@ struct sysmon {
>   	 * that spans multiple regmap calls.
>   	 */
>   	struct mutex lock;
> +	int irq;
>   	/*
>   	 * Protects interrupt mask register updates.  Only used on the
>   	 * MMIO path (fast_io regmap); I2C has no IRQ and never reaches

Change looks good to me.

Reviewed-by: Prasanna Kumar T S M <ptsm@linux.microsoft.com>

Regards,
Prasanna Kumar