Re: [PATCH] sh: maple: use the matching IRQ cookie

[John Paul Adrian Glaubitz]

Hi Florian,

On Sat, 2026-10-17 at 20:22 +0200, Florian Fuchs wrote:
> On 09 Oct 12:02, Runyu Xiao wrote:
> > The Maple DMA and VBLANK handlers are registered with
> > &maple_unsupported_device as their dev_id. Passing NULL to free_irq()
> > cannot find either action, so the handlers remain registered and the
> > IRQ core warns.
> > 
> > Use the same cookie when freeing both handlers on the error paths.
> > 
> > Fixes: 17be2d2b1c33 ("sh: Add maple bus support for the SEGA Dreamcast.")
> > Cc: stable@xxxxxxxxxxxxxxx
> > Assisted-by: LLM
> > Signed-off-by: Runyu Xiao <runyu.xiao@xxxxxxxxxx>
> > ---
> >  drivers/sh/maple/maple.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/sh/maple/maple.c b/drivers/sh/maple/maple.c
> > index 5585f220e..7df88e00c 100644
> > --- a/drivers/sh/maple/maple.c
> > +++ b/drivers/sh/maple/maple.c
> > @@ -863,10 +863,10 @@ static int __init maple_bus_init(void)
> >  	kmem_cache_destroy(maple_queue_cache);
> >  
> >  cleanup_bothirqs:
> > -	free_irq(HW_EVENT_VSYNC, 0);
> > +	free_irq(HW_EVENT_VSYNC, &maple_unsupported_device);
> >  
> >  cleanup_irq:
> > -	free_irq(HW_EVENT_MAPLE_DMA, 0);
> > +	free_irq(HW_EVENT_MAPLE_DMA, &maple_unsupported_device);
> >  
> >  cleanup_dma:
> >  	free_pages((unsigned long) maple_sendbuf, MAPLE_DMA_PAGES);
> > -- 
> > 2.34.1
> 
> The patch looks correct to me and works like intended, that it frees the
> corresponding IRQ handler in the error path.
> 
> Reviewed-By: Florian Fuchs <fuchsfl@xxxxxxxxx>
> Tested-by: Florian Fuchs <fuchsfl@xxxxxxxxx>
> Fixes: b3c69e248176 ("maple: more robust device detection.")
> 
> Just a little addition, it looks like commit b3c69e248176
> ("maple: more robust device detection.") introduced the issue, where the
> static irqaction with IRQF_SHARED, was replaced by a request_irq() with
> a cookie, but the free_irq() wasn't updated.
> 
> I tested the patch with a forced failure of maple_bus_init(), which
> gives the WARNs and keeps the handlers registered in /proc/interrupts:
> Trying to free already-free IRQ 69
> WARNING: kernel/irq/manage.c:1880 at 0x8c0522c4, CPU#0: swapper/0/1
> 
> After the patch, the IRQ handlers are unregistered in /proc/interrupts
> and no kernel WARN is shown.
> 
> And tested if keyboard, mouse still work with the patch, which they do.

Thanks a lot for both the additional review and testing!
Since I'm using b4, it will automatically pick up the Fixes tag you provided.

Will apply the patch tomorrow or Monday.

Adrian

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer
`. `'   Physicist
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