Subject: Re: linux-next: build failure after merge of the hmm tree

From: Stephen Rothwell <[email-masked]>
Date: Tue, 9 Jul 2019 10:21:37 +1000

Hi all,

On Mon, 1 Jul 2019 21:08:53 +1000 Stephen Rothwell <[email-masked]> wrote:
>
> After merging the hmm tree, today's linux-next build (x86_64 allmodconfig)
> failed like this:
> 
> mm/hmm.c: In function 'hmm_get_or_create':
> mm/hmm.c:50:2: error: implicit declaration of function 'lockdep_assert_held_exclusive'; did you mean 'lockdep_assert_held_once'? [-Werror=implicit-function-declaration]
>   lockdep_assert_held_exclusive(&mm->mmap_sem);
>   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>   lockdep_assert_held_once
> 
> Caused by commit
> 
>   8a9320b7ec5d ("mm/hmm: Simplify hmm_get_or_create and make it reliable")
> 
> interacting with commit
> 
>   9ffbe8ac05db ("locking/lockdep: Rename lockdep_assert_held_exclusive() -> lockdep_assert_held_write()")
> 
> from the tip tree.
> 
> I have added the following merge fix.
> 
> From: Stephen Rothwell <[email-masked]>
> Date: Mon, 1 Jul 2019 21:05:59 +1000
> Subject: [PATCH] mm/hmm: fixup for "locking/lockdep: Rename
>  lockdep_assert_held_exclusive() -> lockdep_assert_held_write()"
> 
> Signed-off-by: Stephen Rothwell <[email-masked]>
> ---
>  mm/hmm.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/mm/hmm.c b/mm/hmm.c
> index c1bdcef403ee..2ddbd589b207 100644
> --- a/mm/hmm.c
> +++ b/mm/hmm.c
> @@ -47,7 +47,7 @@ static struct hmm *hmm_get_or_create(struct mm_struct *mm)
>  {
>  	struct hmm *hmm;
>  
> -	lockdep_assert_held_exclusive(&mm->mmap_sem);
> +	lockdep_assert_held_write(&mm->mmap_sem);
>  
>  	/* Abuse the page_table_lock to also protect mm->hmm. */
>  	spin_lock(&mm->page_table_lock);
> @@ -248,7 +248,7 @@ static const struct mmu_notifier_ops hmm_mmu_notifier_ops = {
>   */
>  int hmm_mirror_register(struct hmm_mirror *mirror, struct mm_struct *mm)
>  {
> -	lockdep_assert_held_exclusive(&mm->mmap_sem);
> +	lockdep_assert_held_write(&mm->mmap_sem);
>  
>  	/* Sanity check */
>  	if (!mm || !mirror || !mirror->ops)

I am still getting this conflict (the commit ids may have changed).
Just a reminder in case you think Linus may need to know.

-- 
Cheers,
Stephen Rothwell