Re: Re: [PATCH] dma: at_hdmac: Fix IRQ leak in at_dma_probe()

[Frank Li]

On Fri, May 08, 2026 at 09:33:19AM +0800, dd wrote:
>
>
>
> Hi Frank,
>
> Thanks for your review.

Avoid top post

>
> You're right that in the normal case platform_get_irq() returns the
>
> same value as 'irq'. However, this pattern triggers a smatch warning:
>
>            drivers/dma/at_hdmac.c:2110 at_dma_probe()
>
>            warn: 'irq' from request_irq() not released on lines: 2110.
>
> Static analysis tools cannot guarantee that platform_get_irq() will
>
> always match the previously requested IRQ, so they treat it as a
>
> potential resource leak.

It is false alarm from static analysis tools.

>
> Using the stored 'irq' makes the error path unambiguous and silences
>
> the warning. Therefore I think it qualifies as a small bug fix rather
>
> than just cleanup.

So it still belong code cleanup, no user visible impact.


Frank

>
> Thanks,
>
>
>
> At 2026-05-08 02:24:52, "Frank Li" <Frank.li@xxxxxxx> wrote:
> >On Thu, May 07, 2026 at 03:57:50PM +0800, Hongling Zeng wrote:
> >> When request_irq() succeeds but a later error occurs in at_dma_probe(),
> >> the error handling path attempts to free the IRQ by calling
> >> platform_get_irq() again instead of using the already stored IRQ number
> >> in the local variable 'irq'.
> >>
> >> Fix this by using the stored 'irq' variable directly in free_irq().
> >>
> >> Fixes: dc78baa2b90b2 ("dmaengine: Atmel HDMAC driver")
> >
> >Any actual problem do you meet? suppose it should be the same as 'irq'.
> >
> >of course using varible irq is correct. but this patch should belong code
> >cleanup, not fix.
> >
> >Frank
> >
> >> Signed-off-by: Hongling Zeng <zenghongling@xxxxxxxxxx>
> >> ---
> >>  drivers/dma/at_hdmac.c | 2 +-
> >>  1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
> >> index e5b30a57c477..2a860679b9e1 100644
> >> --- a/drivers/dma/at_hdmac.c
> >> +++ b/drivers/dma/at_hdmac.c
> >> @@ -2109,7 +2109,7 @@ static int __init at_dma_probe(struct platform_device *pdev)
> >>  err_memset_pool_create:
> >>  	dma_pool_destroy(atdma->lli_pool);
> >>  err_desc_pool_create:
> >> -	free_irq(platform_get_irq(pdev, 0), atdma);
> >> +	free_irq(irq, atdma);
> >>  err_irq:
> >>  	clk_disable_unprepare(atdma->clk);
> >>  	return err;
> >> --
> >> 2.25.1
> >>