Re: Is spin_is_locked() safe to use with BUG_ON()/WARN_ON()?

From: Ryan Mallon
Date: Thu May 23 2013 - 21:29:50 EST


On 24/05/13 01:12, David Howells wrote:
> Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
>
>> We do *not* want to add some crazy "spin_is_nt_locked". We just want
>> to get rid of these idiotic debug tests.
>
> Generally, I think you are right, though there are also some checks in
> deallocation routines that check that a spinlock is not currently held before
> releasing the memory holding it - should those be allowed to stay? I'd be
> tempted to wrap the whole check in something, perhaps an "spin_lock_uninit()"
> and move the check to a header file. Would this be useful for lockdep or
> anything like that?

lockdep has lockdep_assert_held(), which might be what you want. Though
it looks like it possibly also has the false positive issues on SMP?

~Ryan

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