On 12/04/2018 04:39 PM, Bart Van Assche wrote: > On Tue, 2018-12-04 at 16:08 -0500, Waiman Long wrote: >> 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. > Hi Waiman, > > Peter asked me to add this check. > > Bart.
I haven't finished reviewing all your patches yet. Maybe one of the subsequent patches requires this. If that is the case, you should move this patch after that. -Longman
