Re: [PATCH] drm: Do not use BUG_ON(!spin_is_locked())

On 08/11/2014 04:45 AM, David Rientjes wrote:

On Sun, 10 Aug 2014, Guenter Roeck wrote:

...

spin_is_locked() always returns false in uniprocessor configurations and can therefore not be used with BUG_ON. Replace it with assert_spin_locked(), which exists for that very purpose.

It may be helpful to assess whether any of these sites should be converted to lockdep_assert_held() so they have no cost when lockdep isn't enabled but still reveal problems when debugging.

Possibly, but that would need to be done by someone with better knowledge about locking and the code than me.

Guenter