Re: [PATCH] iio: trigger: Return an error when the trigger has no free irq

[Joshua Crofts]

On Tue,  6 Oct 2026 05:41:47 +0200
Karl Mehltretter <kmehltretter@xxxxxxxxx> wrote:

> iio_trigger_attach_poll_func() prints an error when all
> CONFIG_IIO_CONSUMERS_PER_TRIGGER irqs of the trigger are in use, but
> returns 0. The buffer of the extra consumer is enabled without a poll
> function.
> 
> Disabling that buffer calls clear_bit() with a negative bit number and
> drops a module reference for the second time. On arm and arm64 the
> clear_bit() goes about 512 MB past the pool bitmap. That is an oops if
> the address is not mapped, and a bit cleared in unrelated memory if it
> is.
> 
> Return the error from iio_trigger_get_irq().
> 
> Fixes: 995438233579 ("iio: Fix error handling in iio_trigger_attach_poll_func")
> Cc: stable@xxxxxxxxxxxxxxx
> Assisted-by: LLM
> Signed-off-by: Karl Mehltretter <kmehltretter@xxxxxxxxx>
> ---

A 10 year old bug. Nice find!

Reviewed-by: Joshua Crofts <joshua.crofts1@xxxxxxxxx>

-- 
Kind regards,
Joshua Crofts