Re: [PATCH v4 7/8] hugetlb: make free_huge_page irq safe

[Oscar Salvador <osalvador@suse.de>]

On Mon, Apr 05, 2021 at 04:00:42PM -0700, Mike Kravetz wrote:
> Commit c77c0a8ac4c5 ("mm/hugetlb: defer freeing of huge pages if in
> non-task context") was added to address the issue of free_huge_page
> being called from irq context.  That commit hands off free_huge_page
> processing to a workqueue if !in_task.  However, this doesn't cover
> all the cases as pointed out by 0day bot lockdep report [1].
> 
> :  Possible interrupt unsafe locking scenario:
> :
> :        CPU0                    CPU1
> :        ----                    ----
> :   lock(hugetlb_lock);
> :                                local_irq_disable();
> :                                lock(slock-AF_INET);
> :                                lock(hugetlb_lock);
> :   <Interrupt>
> :     lock(slock-AF_INET);
> 
> Shakeel has later explained that this is very likely TCP TX zerocopy
> from hugetlb pages scenario when the networking code drops a last
> reference to hugetlb page while having IRQ disabled. Hugetlb freeing
> path doesn't disable IRQ while holding hugetlb_lock so a lock dependency
> chain can lead to a deadlock.
> 
> This commit addresses the issue by doing the following:
> - Make hugetlb_lock irq safe.  This is mostly a simple process of
>   changing spin_*lock calls to spin_*lock_irq* calls.
> - Make subpool lock irq safe in a similar manner.
> - Revert the !in_task check and workqueue handoff.
> 
> [1] https://lore.kernel.org/linux-mm/000000000000f1c03b05bc43aadc@google.com/
> 
> Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
> Acked-by: Michal Hocko <mhocko@suse.com>
> Reviewed-by: Muchun Song <songmuchun@bytedance.com>

So, irq_lock_irqsave/spin_unlock_irqrestore is to be used in places
that might have been called from an IRQ context?

Looks good to me:

Reviewed-by: Oscar Salvador <osalvador@suse.de>

> ---
>  mm/hugetlb.c        | 183 +++++++++++++++++---------------------------
>  mm/hugetlb_cgroup.c |   8 +-
>  2 files changed, 74 insertions(+), 117 deletions(-)
> 
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index 93a2a11b9376..15b6e7aadb52 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -93,9 +93,10 @@ static inline bool subpool_is_free(struct hugepage_subpool *spool)
>  	return true;
>  }
>  
> -static inline void unlock_or_release_subpool(struct hugepage_subpool *spool)
> +static inline void unlock_or_release_subpool(struct hugepage_subpool *spool,
> +						unsigned long irq_flags)
>  {
> -	spin_unlock(&spool->lock);
> +	spin_unlock_irqrestore(&spool->lock, irq_flags);
>  
>  	/* If no pages are used, and no other handles to the subpool
>  	 * remain, give up any reservations based on minimum size and
> @@ -134,10 +135,12 @@ struct hugepage_subpool *hugepage_new_subpool(struct hstate *h, long max_hpages,
>  
>  void hugepage_put_subpool(struct hugepage_subpool *spool)
>  {
> -	spin_lock(&spool->lock);
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&spool->lock, flags);
>  	BUG_ON(!spool->count);
>  	spool->count--;
> -	unlock_or_release_subpool(spool);
> +	unlock_or_release_subpool(spool, flags);
>  }
>  
>  /*
> @@ -156,7 +159,7 @@ static long hugepage_subpool_get_pages(struct hugepage_subpool *spool,
>  	if (!spool)
>  		return ret;
>  
> -	spin_lock(&spool->lock);
> +	spin_lock_irq(&spool->lock);
>  
>  	if (spool->max_hpages != -1) {		/* maximum size accounting */
>  		if ((spool->used_hpages + delta) <= spool->max_hpages)
> @@ -183,7 +186,7 @@ static long hugepage_subpool_get_pages(struct hugepage_subpool *spool,
>  	}
>  
>  unlock_ret:
> -	spin_unlock(&spool->lock);
> +	spin_unlock_irq(&spool->lock);
>  	return ret;
>  }
>  
> @@ -197,11 +200,12 @@ static long hugepage_subpool_put_pages(struct hugepage_subpool *spool,
>  				       long delta)
>  {
>  	long ret = delta;
> +	unsigned long flags;
>  
>  	if (!spool)
>  		return delta;
>  
> -	spin_lock(&spool->lock);
> +	spin_lock_irqsave(&spool->lock, flags);
>  
>  	if (spool->max_hpages != -1)		/* maximum size accounting */
>  		spool->used_hpages -= delta;
> @@ -222,7 +226,7 @@ static long hugepage_subpool_put_pages(struct hugepage_subpool *spool,
>  	 * If hugetlbfs_put_super couldn't free spool due to an outstanding
>  	 * quota reference, free it now.
>  	 */
> -	unlock_or_release_subpool(spool);
> +	unlock_or_release_subpool(spool, flags);
>  
>  	return ret;
>  }
> @@ -1407,7 +1411,7 @@ struct hstate *size_to_hstate(unsigned long size)
>  	return NULL;
>  }
>  
> -static void __free_huge_page(struct page *page)
> +void free_huge_page(struct page *page)
>  {
>  	/*
>  	 * Can't pass hstate in here because it is called from the
> @@ -1417,6 +1421,7 @@ static void __free_huge_page(struct page *page)
>  	int nid = page_to_nid(page);
>  	struct hugepage_subpool *spool = hugetlb_page_subpool(page);
>  	bool restore_reserve;
> +	unsigned long flags;
>  
>  	VM_BUG_ON_PAGE(page_count(page), page);
>  	VM_BUG_ON_PAGE(page_mapcount(page), page);
> @@ -1445,7 +1450,7 @@ static void __free_huge_page(struct page *page)
>  			restore_reserve = true;
>  	}
>  
> -	spin_lock(&hugetlb_lock);
> +	spin_lock_irqsave(&hugetlb_lock, flags);
>  	ClearHPageMigratable(page);
>  	hugetlb_cgroup_uncharge_page(hstate_index(h),
>  				     pages_per_huge_page(h), page);
> @@ -1456,66 +1461,18 @@ static void __free_huge_page(struct page *page)
>  
>  	if (HPageTemporary(page)) {
>  		remove_hugetlb_page(h, page, false);
> -		spin_unlock(&hugetlb_lock);
> +		spin_unlock_irqrestore(&hugetlb_lock, flags);
>  		update_and_free_page(h, page);
>  	} else if (h->surplus_huge_pages_node[nid]) {
>  		/* remove the page from active list */
>  		remove_hugetlb_page(h, page, true);
> -		spin_unlock(&hugetlb_lock);
> +		spin_unlock_irqrestore(&hugetlb_lock, flags);
>  		update_and_free_page(h, page);
>  	} else {
>  		arch_clear_hugepage_flags(page);
>  		enqueue_huge_page(h, page);
> -		spin_unlock(&hugetlb_lock);
> -	}
> -}
> -
> -/*
> - * As free_huge_page() can be called from a non-task context, we have
> - * to defer the actual freeing in a workqueue to prevent potential
> - * hugetlb_lock deadlock.
> - *
> - * free_hpage_workfn() locklessly retrieves the linked list of pages to
> - * be freed and frees them one-by-one. As the page->mapping pointer is
> - * going to be cleared in __free_huge_page() anyway, it is reused as the
> - * llist_node structure of a lockless linked list of huge pages to be freed.
> - */
> -static LLIST_HEAD(hpage_freelist);
> -
> -static void free_hpage_workfn(struct work_struct *work)
> -{
> -	struct llist_node *node;
> -	struct page *page;
> -
> -	node = llist_del_all(&hpage_freelist);
> -
> -	while (node) {
> -		page = container_of((struct address_space **)node,
> -				     struct page, mapping);
> -		node = node->next;
> -		__free_huge_page(page);
> -	}
> -}
> -static DECLARE_WORK(free_hpage_work, free_hpage_workfn);
> -
> -void free_huge_page(struct page *page)
> -{
> -	/*
> -	 * Defer freeing if in non-task context to avoid hugetlb_lock deadlock.
> -	 */
> -	if (!in_task()) {
> -		/*
> -		 * Only call schedule_work() if hpage_freelist is previously
> -		 * empty. Otherwise, schedule_work() had been called but the
> -		 * workfn hasn't retrieved the list yet.
> -		 */
> -		if (llist_add((struct llist_node *)&page->mapping,
> -			      &hpage_freelist))
> -			schedule_work(&free_hpage_work);
> -		return;
> +		spin_unlock_irqrestore(&hugetlb_lock, flags);
>  	}
> -
> -	__free_huge_page(page);
>  }
>  
>  static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
> @@ -1525,11 +1482,11 @@ static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
>  	hugetlb_set_page_subpool(page, NULL);
>  	set_hugetlb_cgroup(page, NULL);
>  	set_hugetlb_cgroup_rsvd(page, NULL);
> -	spin_lock(&hugetlb_lock);
> +	spin_lock_irq(&hugetlb_lock);
>  	h->nr_huge_pages++;
>  	h->nr_huge_pages_node[nid]++;
>  	ClearHPageFreed(page);
> -	spin_unlock(&hugetlb_lock);
> +	spin_unlock_irq(&hugetlb_lock);
>  }
>  
>  static void prep_compound_gigantic_page(struct page *page, unsigned int order)
> @@ -1775,7 +1732,7 @@ int dissolve_free_huge_page(struct page *page)
>  	if (!PageHuge(page))
>  		return 0;
>  
> -	spin_lock(&hugetlb_lock);
> +	spin_lock_irq(&hugetlb_lock);
>  	if (!PageHuge(page)) {
>  		rc = 0;
>  		goto out;
> @@ -1792,7 +1749,7 @@ int dissolve_free_huge_page(struct page *page)
>  		 * when it is dissolved.
>  		 */
>  		if (unlikely(!HPageFreed(head))) {
> -			spin_unlock(&hugetlb_lock);
> +			spin_unlock_irq(&hugetlb_lock);
>  			cond_resched();
>  
>  			/*
> @@ -1816,12 +1773,12 @@ int dissolve_free_huge_page(struct page *page)
>  		}
>  		remove_hugetlb_page(h, page, false);
>  		h->max_huge_pages--;
> -		spin_unlock(&hugetlb_lock);
> +		spin_unlock_irq(&hugetlb_lock);
>  		update_and_free_page(h, head);
>  		return 0;
>  	}
>  out:
> -	spin_unlock(&hugetlb_lock);
> +	spin_unlock_irq(&hugetlb_lock);
>  	return rc;
>  }
>  
> @@ -1863,16 +1820,16 @@ static struct page *alloc_surplus_huge_page(struct hstate *h, gfp_t gfp_mask,
>  	if (hstate_is_gigantic(h))
>  		return NULL;
>  
> -	spin_lock(&hugetlb_lock);
> +	spin_lock_irq(&hugetlb_lock);
>  	if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages)
>  		goto out_unlock;
> -	spin_unlock(&hugetlb_lock);
> +	spin_unlock_irq(&hugetlb_lock);
>  
>  	page = alloc_fresh_huge_page(h, gfp_mask, nid, nmask, NULL);
>  	if (!page)
>  		return NULL;
>  
> -	spin_lock(&hugetlb_lock);
> +	spin_lock_irq(&hugetlb_lock);
>  	/*
>  	 * We could have raced with the pool size change.
>  	 * Double check that and simply deallocate the new page
> @@ -1882,7 +1839,7 @@ static struct page *alloc_surplus_huge_page(struct hstate *h, gfp_t gfp_mask,
>  	 */
>  	if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
>  		SetHPageTemporary(page);
> -		spin_unlock(&hugetlb_lock);
> +		spin_unlock_irq(&hugetlb_lock);
>  		put_page(page);
>  		return NULL;
>  	} else {
> @@ -1891,7 +1848,7 @@ static struct page *alloc_surplus_huge_page(struct hstate *h, gfp_t gfp_mask,
>  	}
>  
>  out_unlock:
> -	spin_unlock(&hugetlb_lock);
> +	spin_unlock_irq(&hugetlb_lock);
>  
>  	return page;
>  }
> @@ -1941,17 +1898,17 @@ struct page *alloc_buddy_huge_page_with_mpol(struct hstate *h,
>  struct page *alloc_huge_page_nodemask(struct hstate *h, int preferred_nid,
>  		nodemask_t *nmask, gfp_t gfp_mask)
>  {
> -	spin_lock(&hugetlb_lock);
> +	spin_lock_irq(&hugetlb_lock);
>  	if (h->free_huge_pages - h->resv_huge_pages > 0) {
>  		struct page *page;
>  
>  		page = dequeue_huge_page_nodemask(h, gfp_mask, preferred_nid, nmask);
>  		if (page) {
> -			spin_unlock(&hugetlb_lock);
> +			spin_unlock_irq(&hugetlb_lock);
>  			return page;
>  		}
>  	}
> -	spin_unlock(&hugetlb_lock);
> +	spin_unlock_irq(&hugetlb_lock);
>  
>  	return alloc_migrate_huge_page(h, gfp_mask, preferred_nid, nmask);
>  }
> @@ -1999,7 +1956,7 @@ static int gather_surplus_pages(struct hstate *h, long delta)
>  
>  	ret = -ENOMEM;
>  retry:
> -	spin_unlock(&hugetlb_lock);
> +	spin_unlock_irq(&hugetlb_lock);
>  	for (i = 0; i < needed; i++) {
>  		page = alloc_surplus_huge_page(h, htlb_alloc_mask(h),
>  				NUMA_NO_NODE, NULL);
> @@ -2016,7 +1973,7 @@ static int gather_surplus_pages(struct hstate *h, long delta)
>  	 * After retaking hugetlb_lock, we need to recalculate 'needed'
>  	 * because either resv_huge_pages or free_huge_pages may have changed.
>  	 */
> -	spin_lock(&hugetlb_lock);
> +	spin_lock_irq(&hugetlb_lock);
>  	needed = (h->resv_huge_pages + delta) -
>  			(h->free_huge_pages + allocated);
>  	if (needed > 0) {
> @@ -2056,12 +2013,12 @@ static int gather_surplus_pages(struct hstate *h, long delta)
>  		enqueue_huge_page(h, page);
>  	}
>  free:
> -	spin_unlock(&hugetlb_lock);
> +	spin_unlock_irq(&hugetlb_lock);
>  
>  	/* Free unnecessary surplus pages to the buddy allocator */
>  	list_for_each_entry_safe(page, tmp, &surplus_list, lru)
>  		put_page(page);
> -	spin_lock(&hugetlb_lock);
> +	spin_lock_irq(&hugetlb_lock);
>  
>  	return ret;
>  }
> @@ -2111,9 +2068,9 @@ static void return_unused_surplus_pages(struct hstate *h,
>  	}
>  
>  out:
> -	spin_unlock(&hugetlb_lock);
> +	spin_unlock_irq(&hugetlb_lock);
>  	update_and_free_pages_bulk(h, &page_list);
> -	spin_lock(&hugetlb_lock);
> +	spin_lock_irq(&hugetlb_lock);
>  }
>  
>  
> @@ -2316,7 +2273,7 @@ static int alloc_and_dissolve_huge_page(struct hstate *h, struct page *old_page,
>  	 */
>  	page_ref_dec(new_page);
>  retry:
> -	spin_lock(&hugetlb_lock);
> +	spin_lock_irq(&hugetlb_lock);
>  	if (!PageHuge(old_page)) {
>  		/*
>  		 * Freed from under us. Drop new_page too.
> @@ -2330,7 +2287,7 @@ static int alloc_and_dissolve_huge_page(struct hstate *h, struct page *old_page,
>  		 * Fail with -EBUSY if not possible.
>  		 */
>  		remove_hugetlb_page(h, new_page, false);
> -		spin_unlock(&hugetlb_lock);
> +		spin_unlock_irq(&hugetlb_lock);
>  		update_and_free_page(h, new_page);
>  		if (!isolate_huge_page(old_page, list))
>  			ret = -EBUSY;
> @@ -2341,7 +2298,7 @@ static int alloc_and_dissolve_huge_page(struct hstate *h, struct page *old_page,
>  		 * freelist yet. Race window is small, so we can succed here if
>  		 * we retry.
>  		 */
> -		spin_unlock(&hugetlb_lock);
> +		spin_unlock_irq(&hugetlb_lock);
>  		cond_resched();
>  		goto retry;
>  	} else {
> @@ -2357,7 +2314,7 @@ static int alloc_and_dissolve_huge_page(struct hstate *h, struct page *old_page,
>  		page_to_free = old_page;
>  	}
>  unlock_free:
> -	spin_unlock(&hugetlb_lock);
> +	spin_unlock_irq(&hugetlb_lock);
>  	update_and_free_page(h, page_to_free);
>  
>  	return ret;
> @@ -2374,15 +2331,15 @@ int isolate_or_dissolve_huge_page(struct page *page, struct list_head *list)
>  	 * to carefully check the state under the lock.
>  	 * Return success when racing as if we dissolved the page ourselves.
>  	 */
> -	spin_lock(&hugetlb_lock);
> +	spin_lock_irq(&hugetlb_lock);
>  	if (PageHuge(page)) {
>  		head = compound_head(page);
>  		h = page_hstate(head);
>  	} else {
> -		spin_unlock(&hugetlb_lock);
> +		spin_unlock_irq(&hugetlb_lock);
>  		return 0;
>  	}
> -	spin_unlock(&hugetlb_lock);
> +	spin_unlock_irq(&hugetlb_lock);
>  
>  	/*
>  	 * Fence off gigantic pages as there is a cyclic dependency between
> @@ -2462,7 +2419,7 @@ struct page *alloc_huge_page(struct vm_area_struct *vma,
>  	if (ret)
>  		goto out_uncharge_cgroup_reservation;
>  
> -	spin_lock(&hugetlb_lock);
> +	spin_lock_irq(&hugetlb_lock);
>  	/*
>  	 * glb_chg is passed to indicate whether or not a page must be taken
>  	 * from the global free pool (global change).  gbl_chg == 0 indicates
> @@ -2470,7 +2427,7 @@ struct page *alloc_huge_page(struct vm_area_struct *vma,
>  	 */
>  	page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve, gbl_chg);
>  	if (!page) {
> -		spin_unlock(&hugetlb_lock);
> +		spin_unlock_irq(&hugetlb_lock);
>  		page = alloc_buddy_huge_page_with_mpol(h, vma, addr);
>  		if (!page)
>  			goto out_uncharge_cgroup;
> @@ -2478,7 +2435,7 @@ struct page *alloc_huge_page(struct vm_area_struct *vma,
>  			SetHPageRestoreReserve(page);
>  			h->resv_huge_pages--;
>  		}
> -		spin_lock(&hugetlb_lock);
> +		spin_lock_irq(&hugetlb_lock);
>  		list_add(&page->lru, &h->hugepage_activelist);
>  		/* Fall through */
>  	}
> @@ -2491,7 +2448,7 @@ struct page *alloc_huge_page(struct vm_area_struct *vma,
>  						  h_cg, page);
>  	}
>  
> -	spin_unlock(&hugetlb_lock);
> +	spin_unlock_irq(&hugetlb_lock);
>  
>  	hugetlb_set_page_subpool(page, spool);
>  
> @@ -2703,9 +2660,9 @@ static void try_to_free_low(struct hstate *h, unsigned long count,
>  	}
>  
>  out:
> -	spin_unlock(&hugetlb_lock);
> +	spin_unlock_irq(&hugetlb_lock);
>  	update_and_free_pages_bulk(h, &page_list);
> -	spin_lock(&hugetlb_lock);
> +	spin_lock_irq(&hugetlb_lock);
>  }
>  #else
>  static inline void try_to_free_low(struct hstate *h, unsigned long count,
> @@ -2770,7 +2727,7 @@ static int set_max_huge_pages(struct hstate *h, unsigned long count, int nid,
>  	 * pages in hstate via the proc/sysfs interfaces.
>  	 */
>  	mutex_lock(&h->resize_lock);
> -	spin_lock(&hugetlb_lock);
> +	spin_lock_irq(&hugetlb_lock);
>  
>  	/*
>  	 * Check for a node specific request.
> @@ -2801,7 +2758,7 @@ static int set_max_huge_pages(struct hstate *h, unsigned long count, int nid,
>  	 */
>  	if (hstate_is_gigantic(h) && !IS_ENABLED(CONFIG_CONTIG_ALLOC)) {
>  		if (count > persistent_huge_pages(h)) {
> -			spin_unlock(&hugetlb_lock);
> +			spin_unlock_irq(&hugetlb_lock);
>  			mutex_unlock(&h->resize_lock);
>  			NODEMASK_FREE(node_alloc_noretry);
>  			return -EINVAL;
> @@ -2831,14 +2788,14 @@ static int set_max_huge_pages(struct hstate *h, unsigned long count, int nid,
>  		 * page, free_huge_page will handle it by freeing the page
>  		 * and reducing the surplus.
>  		 */
> -		spin_unlock(&hugetlb_lock);
> +		spin_unlock_irq(&hugetlb_lock);
>  
>  		/* yield cpu to avoid soft lockup */
>  		cond_resched();
>  
>  		ret = alloc_pool_huge_page(h, nodes_allowed,
>  						node_alloc_noretry);
> -		spin_lock(&hugetlb_lock);
> +		spin_lock_irq(&hugetlb_lock);
>  		if (!ret)
>  			goto out;
>  
> @@ -2877,9 +2834,9 @@ static int set_max_huge_pages(struct hstate *h, unsigned long count, int nid,
>  		list_add(&page->lru, &page_list);
>  	}
>  	/* free the pages after dropping lock */
> -	spin_unlock(&hugetlb_lock);
> +	spin_unlock_irq(&hugetlb_lock);
>  	update_and_free_pages_bulk(h, &page_list);
> -	spin_lock(&hugetlb_lock);
> +	spin_lock_irq(&hugetlb_lock);
>  
>  	while (count < persistent_huge_pages(h)) {
>  		if (!adjust_pool_surplus(h, nodes_allowed, 1))
> @@ -2887,7 +2844,7 @@ static int set_max_huge_pages(struct hstate *h, unsigned long count, int nid,
>  	}
>  out:
>  	h->max_huge_pages = persistent_huge_pages(h);
> -	spin_unlock(&hugetlb_lock);
> +	spin_unlock_irq(&hugetlb_lock);
>  	mutex_unlock(&h->resize_lock);
>  
>  	NODEMASK_FREE(node_alloc_noretry);
> @@ -3043,9 +3000,9 @@ static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj,
>  	if (err)
>  		return err;
>  
> -	spin_lock(&hugetlb_lock);
> +	spin_lock_irq(&hugetlb_lock);
>  	h->nr_overcommit_huge_pages = input;
> -	spin_unlock(&hugetlb_lock);
> +	spin_unlock_irq(&hugetlb_lock);
>  
>  	return count;
>  }
> @@ -3632,9 +3589,9 @@ int hugetlb_overcommit_handler(struct ctl_table *table, int write,
>  		goto out;
>  
>  	if (write) {
> -		spin_lock(&hugetlb_lock);
> +		spin_lock_irq(&hugetlb_lock);
>  		h->nr_overcommit_huge_pages = tmp;
> -		spin_unlock(&hugetlb_lock);
> +		spin_unlock_irq(&hugetlb_lock);
>  	}
>  out:
>  	return ret;
> @@ -3730,7 +3687,7 @@ static int hugetlb_acct_memory(struct hstate *h, long delta)
>  	if (!delta)
>  		return 0;
>  
> -	spin_lock(&hugetlb_lock);
> +	spin_lock_irq(&hugetlb_lock);
>  	/*
>  	 * When cpuset is configured, it breaks the strict hugetlb page
>  	 * reservation as the accounting is done on a global variable. Such
> @@ -3769,7 +3726,7 @@ static int hugetlb_acct_memory(struct hstate *h, long delta)
>  		return_unused_surplus_pages(h, (unsigned long) -delta);
>  
>  out:
> -	spin_unlock(&hugetlb_lock);
> +	spin_unlock_irq(&hugetlb_lock);
>  	return ret;
>  }
>  
> @@ -5833,7 +5790,7 @@ bool isolate_huge_page(struct page *page, struct list_head *list)
>  {
>  	bool ret = true;
>  
> -	spin_lock(&hugetlb_lock);
> +	spin_lock_irq(&hugetlb_lock);
>  	if (!PageHeadHuge(page) ||
>  	    !HPageMigratable(page) ||
>  	    !get_page_unless_zero(page)) {
> @@ -5843,16 +5800,16 @@ bool isolate_huge_page(struct page *page, struct list_head *list)
>  	ClearHPageMigratable(page);
>  	list_move_tail(&page->lru, list);
>  unlock:
> -	spin_unlock(&hugetlb_lock);
> +	spin_unlock_irq(&hugetlb_lock);
>  	return ret;
>  }
>  
>  void putback_active_hugepage(struct page *page)
>  {
> -	spin_lock(&hugetlb_lock);
> +	spin_lock_irq(&hugetlb_lock);
>  	SetHPageMigratable(page);
>  	list_move_tail(&page->lru, &(page_hstate(page))->hugepage_activelist);
> -	spin_unlock(&hugetlb_lock);
> +	spin_unlock_irq(&hugetlb_lock);
>  	put_page(page);
>  }
>  
> @@ -5886,12 +5843,12 @@ void move_hugetlb_state(struct page *oldpage, struct page *newpage, int reason)
>  		 */
>  		if (new_nid == old_nid)
>  			return;
> -		spin_lock(&hugetlb_lock);
> +		spin_lock_irq(&hugetlb_lock);
>  		if (h->surplus_huge_pages_node[old_nid]) {
>  			h->surplus_huge_pages_node[old_nid]--;
>  			h->surplus_huge_pages_node[new_nid]++;
>  		}
> -		spin_unlock(&hugetlb_lock);
> +		spin_unlock_irq(&hugetlb_lock);
>  	}
>  }
>  
> diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c
> index 726b85f4f303..5383023d0cca 100644
> --- a/mm/hugetlb_cgroup.c
> +++ b/mm/hugetlb_cgroup.c
> @@ -204,11 +204,11 @@ static void hugetlb_cgroup_css_offline(struct cgroup_subsys_state *css)
>  	do {
>  		idx = 0;
>  		for_each_hstate(h) {
> -			spin_lock(&hugetlb_lock);
> +			spin_lock_irq(&hugetlb_lock);
>  			list_for_each_entry(page, &h->hugepage_activelist, lru)
>  				hugetlb_cgroup_move_parent(idx, h_cg, page);
>  
> -			spin_unlock(&hugetlb_lock);
> +			spin_unlock_irq(&hugetlb_lock);
>  			idx++;
>  		}
>  		cond_resched();
> @@ -784,7 +784,7 @@ void hugetlb_cgroup_migrate(struct page *oldhpage, struct page *newhpage)
>  	if (hugetlb_cgroup_disabled())
>  		return;
>  
> -	spin_lock(&hugetlb_lock);
> +	spin_lock_irq(&hugetlb_lock);
>  	h_cg = hugetlb_cgroup_from_page(oldhpage);
>  	h_cg_rsvd = hugetlb_cgroup_from_page_rsvd(oldhpage);
>  	set_hugetlb_cgroup(oldhpage, NULL);
> @@ -794,7 +794,7 @@ void hugetlb_cgroup_migrate(struct page *oldhpage, struct page *newhpage)
>  	set_hugetlb_cgroup(newhpage, h_cg);
>  	set_hugetlb_cgroup_rsvd(newhpage, h_cg_rsvd);
>  	list_move(&newhpage->lru, &h->hugepage_activelist);
> -	spin_unlock(&hugetlb_lock);
> +	spin_unlock_irq(&hugetlb_lock);
>  	return;
>  }
>  
> -- 
> 2.30.2
> 

-- 
Oscar Salvador
SUSE L3