Re: + kernel-locking-lockdepc-make-lockdep-initialize-itself-on-demand.patch added to -mm tree

[Andrey Ryabinin]

On 02/29/2016 12:25 PM, Ingo Molnar wrote:
> 
> * Ingo Molnar <mingo@xxxxxxxxxx> wrote:
> 
>>
>> * Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
>>
>>> On Tue, 9 Feb 2016 12:12:29 +0100 Ingo Molnar <mingo@xxxxxxxxxx> wrote:
>>>
>>>>> The conceptual problem is that if some piece of code does spin_lock_init() or 
>>>>> DEFINE_SPINLOCK(), that lock isn't necessarily initialized yet.
>>>>
>>>> The conceptual problem is that the data structures are not build time initialized 
>>>> - but the hlist conversion patch solves that problem nicely!
>>>>
>>>> So I'm a happy camper.
>>>
>>> OK, so the below has been in -next for nearly a week, no issues.  We
>>> should get this into 4.5 to fix the CONFIG_UBSAN_ALIGNMENT issue.
>>
>> So I think this patch broke liblockdep:
>>
>> triton:~/tip/tools/lib/lockdep> 
>>
>> In file included from lockdep.c:2:0:
>> ../../../kernel/locking/lockdep.c: In function âlook_up_lock_classâ:
>> ../../../kernel/locking/lockdep.c:722:2: warning: implicit declaration of function âhlist_for_each_entry_rcuâ [-Wimplicit-function-declaration]
>>   hlist_for_each_entry_rcu(class, hash_head, hash_entry) {
> 
> The patch below fixes it.
> 
> Thanks,
> 
> 	Ingo
> 
>  tools/lib/lockdep/lockdep.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/tools/lib/lockdep/lockdep.c b/tools/lib/lockdep/lockdep.c
> index f42b7e9aa48f..a0a2e3a266af 100644
> --- a/tools/lib/lockdep/lockdep.c
> +++ b/tools/lib/lockdep/lockdep.c
> @@ -1,2 +1,8 @@
>  #include <linux/lockdep.h>
> +
> +/* Trivial API wrappers, we don't (yet) have RCU in user-space: */
> +#define hlist_for_each_entry_rcu	hlist_for_each_entry
> +#define hlist_add_head_rcu		hlist_add_head
> +#define hlist_del_rcu			hlist_del
> +

I think this belongs to tools/lib/lockdep/uinclude/linux/kernel.h