Re: [parisc-linux] spinlock debug

[Grant Grundler <grundler@parisc-linux.org>]

On Tue, Jul 13, 2004 at 09:29:10PM -0700, Randolph Chung wrote:
> I don't think the comment is correct.

The comment is *mostly* correct.
It just doesn't get all the exit criteria right. :^)

> Lets say someone is holding the
> lock when you enter this code, your outer loop test always succeeds, and
> you spin on the inner loop until stuck == 0. At that point you go back
> to the outer loop, the lock is still held, so you go back to the inner
> loop and continue spinning, and you never timeout the lock.

Yup - good catch.

> you probably need a "&& stuck > 0" in the outer loop.

Yes. This should be sufficient:
        a = __ldcw_align(lock);
        while ((__ldcw(a) == 0) && stuck)
                while ((*a == 0) && --stuck);

> for some reason this still doesn't work for me though, but i don't see 
> why :( with a TOC i see we are spinning and i never see the printk.
> it might be that it's actually printing and just that the output is not
> going to the console... dunno

Do you happen to know which lock it's spinning on?
That should at least reduce the subset of code we need to look at.

grant
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