"Trying to free already-free IRQ 9", but it wasn't freed by me

[mayur nande]

Hi Nils,

>>void cleanup_module(void) {
 >>   ...
  >>  free_irq(ADC_IRQ, NULL);        /* remove interrupt handler */
  >>  ...
  >>   return;
>>}

You should not pass NULL here. It should be the unique cookie that you
passed in request_irq (adc_irq_handler in your case) since you have used
IRQF_SHARED which means you want to share your interrupt line. Also check
whether you really want to share your interrupt line and also if you want
to use "(void *)(adc_irq_handler)" as the unique identification.

HTH!

Regards
Mayur

On Tue, Feb 7, 2012 at 7:45 PM, nils.stec <nils.stec at googlemail.com> wrote:

>  Hi,
>
> atm I'm writing a kernel module for an embedded ARM device.
> This module uses IRQ9.
>
> If i remove the module, the kernel tells me that:
>
> ------------[ cut here ]------------
> WARNING: at kernel/irq/manage.c:858 __free_irq+0x84/0x154()
> Trying to free already-free IRQ 9
> Modules linked in: adc_demo_irq(P-) g_ether pegasus mii
> [<c0028794>] (unwind_backtrace+0x0/0xd0) from [<c003b504>]
> (warn_slowpath_common+0x48/0x60)
> [<c003b504>] (warn_slowpath_common+0x48/0x60) from [<c003b554>]
> (warn_slowpath_fmt+0x24/0x30)
> [<c003b554>] (warn_slowpath_fmt+0x24/0x30) from [<c005fa00>]
> (__free_irq+0x84/0x154)
> [<c005fa00>] (__free_irq+0x84/0x154) from [<c005fb0c>]
> (free_irq+0x3c/0x5c)
> [<c005fb0c>] (free_irq+0x3c/0x5c) from [<bf01e18c>]
> (cleanup_module+0x4c/0x60 [adc_demo_irq])
> [<bf01e18c>] (cleanup_module+0x4c/0x60 [adc_demo_irq]) from [<c005b898>]
> (sys_delete_module+0x1c4/0x238)
> [<c005b898>] (sys_delete_module+0x1c4/0x238) from [<c0022dc0>]
> (ret_fast_syscall+0x0/0x28)
> ---[ end trace 60d7a16d878ac0b3 ]---
> adc testing module removed
> ------------[ cut here ]------------
>
> The message "adc testing module removed" comes from my module **after**free_irq() via printk, so the module exit routine works till the end.
>
> This is my code (only the IRQ related part):
>
> irqreturn_t adc_irq_handler(int irq, void *dev_id) {
>
>     ... do someting ...
>
>     return IRQ_HANDLED;
> }
>
> int init_module(void) {
>     int32_t retval;
>     ...
>     retval = request_irq(ADC_IRQ, adc_irq_handler, IRQF_SHARED, "lpc313x
> adc irq", (void *)(adc_irq_handler));
>     ...
>     return retval;
> }
>
> void cleanup_module(void) {
>     ...
>     free_irq(ADC_IRQ, NULL);        /* remove interrupt handler */
>     ...
>     return;
> }
>
>
> I hope anyone of you can help me with that problem. If you need more
> information, i'll send it
>
> Greetings,
> Nils
>
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>
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