On 12/03/2018 07:28 PM, Bart Van Assche wrote: > Cc: Peter Zijlstra <[email protected]> > Cc: Waiman Long <[email protected]> > Cc: Johannes Berg <[email protected]> > Signed-off-by: Bart Van Assche <[email protected]> > --- > kernel/locking/lockdep.c | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c > index c936fce5b9d7..b4772e5fc176 100644 > --- a/kernel/locking/lockdep.c > +++ b/kernel/locking/lockdep.c > @@ -727,6 +727,15 @@ static bool assign_lock_key(struct lockdep_map *lock) > { > unsigned long can_addr, addr = (unsigned long)lock; > > + /* > + * lockdep_free_key_range() assumes that struct lock_class_key > + * objects do not overlap. Since we use the address of lock > + * objects as class key for static objects, check whether the > + * size of lock_class_key objects does not exceed the size of > + * the smallest lock object. > + */ > + BUILD_BUG_ON(sizeof(struct lock_class_key) > sizeof(raw_spinlock_t)); > + > if (__is_kernel_percpu_address(addr, &can_addr)) > lock->key = (void *)can_addr; > else if (__is_module_percpu_address(addr, &can_addr))
I don't understand what this check is for. lock_class_key and spinlock are different objects. Their relative size shouldn't matter. Cheers, Longman
