Re: [PATCH v2 08/13] dmaengine: ste_dma40: Fix probe IRQ leak

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:

Pre-existing issues:
- [High] Hardware interrupt is requested before hardware initialization and Runtime PM enablement, creating a window for an immediate IRQ storm.
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--- Patch [8]: [PATCH v2 08/13] dmaengine: ste_dma40: Fix probe IRQ leak ---
commit e1b29c17ec30abafeb3d5100e10a174f78b73842
Author: Linus Walleij <linusw@kernel.org>

dmaengine: ste_dma40: Fix probe IRQ leak

This commit fixes an IRQ leak in the probe error paths of the ste_dma40 driver
by tracking whether the IRQ was successfully requested and freeing it during
failure teardown.

Reported-by: sashiko-bot@kernel.org
Closes: https://lore.kernel.org/dmaengine/20260618051539.15E201F000E9@smtp.kernel.org/
Assisted-by: Codex:gpt-5-5
Signed-off-by: Linus Walleij <linusw@kernel.org>

> diff --git a/drivers/dma/ste_dma40.c b/drivers/dma/ste_dma40.c
> index 0c9094b4c4ade..8cf73b37f8bfd 100644
> --- a/drivers/dma/ste_dma40.c
> +++ b/drivers/dma/ste_dma40.c
[ ... ]
> @@ -3605,6 +3606,7 @@ static int __init d40_probe(struct platform_device *pdev)
>  		d40_err(dev, "No IRQ defined\n");
>  		goto destroy_cache;
>  	}
> +	irq_requested = true;

[Severity: High]
This is a pre-existing issue, but does requesting the IRQ here create a
window for an immediate interrupt storm?

The interrupt is requested in d40_probe() before hardware initialization
(d40_hw_init()) and Runtime PM enablement (pm_runtime_enable()). If the
hardware interrupt is already asserted (for example, if left pending by a
bootloader), it will fire immediately.

Inside d40_handle_interrupt(), the handler checks Runtime PM status:

drivers/dma/ste_dma40.c:d40_handle_interrupt() {
    ...
	ret = pm_runtime_get_if_active(base->dev);
	if (ret <= 0)
		return IRQ_NONE;
    ...
}

Since pm_runtime_set_active() and pm_runtime_enable() have not yet been
executed in d40_probe(), Runtime PM is inactive. This causes the check to
fail, returning IRQ_NONE without servicing or clearing the hardware
interrupt.

For level-triggered interrupts, could this lead to an unhandled interrupt
storm that permanently disables the device's IRQ line?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260820-dma40-fixes-v2-0-63238334c707@kernel.org?part=8