Re: System hangs during interruptible_sleep_on_timeout() under 2.4.9

[Norbert Roos]

Ingo Molnar wrote:

> are you sure timer interrupts are processed while you are waiting for the
> timeout to expire? I'd suggest to put a:
> 
>         printk("<%d>", irq);
> 
> into arch/i386/kernel/irq.c:do_IRQ().

Until the call of interruptible_sleep_on_timeout(), timer interrupts
were processed. Right after the call no more output is made.

> So you can see what kind of
> interrupt traffic there is while the device initializes and you are
> waiting for it to generate an interrupt.

I use the function only for a short delay (switch on the device's reset,
wait and switch it off again), so the device even does not generate a
PCI interrupt.

In the time inbetween I have traced the problem: Inside the sleep_on()
functions there is the macro SLEEP_ON_HEAD containing the call
wq_write_lock_irqsave(), where the error happens. This is a macro, too,
which at last expands to

__asm__ __volatile__("pushfl ; popl %0":"=g" (x): /* no input */)

(x ist the variable where the IRQ flags are stored)
I'm not familiar with x86 assembler; is it possible that something can
go wrong here?

bye, Norbert