Re: Wait queue crash

[Manfred Spraul]

Suresh Thennarangam wrote:
> 
> We are having this problem with wait queues on linux 2.3.28 kernel
> (and 2.2.12 as well)
> The code is simple .. and it crashes. I can see other code in
> the linux usb stack using exactly the same thing. Does anyone
> have a clue ?  I've read about reentrancy issues but the code
> here doesn't really do much. Thanks for your input.
> 

* don't use interruptible_sleep_on(), the function can lock up unless
your code is protected by the big kernel lock [and new code shoudn't
rely on that lock].
If your code doesn't need any spinlocks, then you could use
wait_event_interruptible(), otherwise copy the code from
wait_event_interruptible() and release your spinlock just before calling
schedule().

*
> static void     intr_handler(void *ptr)
> {
> 
>    mc_tq_task.routine = defered_proc;
>    mc_tq_task.data    = dev;
> 
>    init_waitqueue_head(&mc_tq_wait);
> 
>    queue_task(&mc_tq_task, &tq_scheduler);
>    interruptible_sleep_on(&mc_tq_wait);
> 
> }

Do you try to sleep within the interrupt handler? You can't do that.

--
	Manfred