On Tue, Apr 16, 2019 at 03:45:06PM +0200, Laurent Dufour wrote:
> The speculative page fault handler which is run without holding the
> mmap_sem is calling lru_cache_add_active_or_unevictable() but the vm_flags
> is not guaranteed to remain constant.
> Introducing __lru_cache_add_active_or_unevictable() which has the vma flags
> value parameter instead of the vma pointer.
>
> Acked-by: David Rientjes <rient...@google.com>
> Signed-off-by: Laurent Dufour <lduf...@linux.ibm.com>
Reviewed-by: Jérôme Glisse <jgli...@redhat.com>
> ---
> include/linux/swap.h | 10 ++++++++--
> mm/memory.c | 8 ++++----
> mm/swap.c | 6 +++---
> 3 files changed, 15 insertions(+), 9 deletions(-)
>
> diff --git a/include/linux/swap.h b/include/linux/swap.h
> index 4bfb5c4ac108..d33b94eb3c69 100644
> --- a/include/linux/swap.h
> +++ b/include/linux/swap.h
> @@ -343,8 +343,14 @@ extern void deactivate_file_page(struct page *page);
> extern void mark_page_lazyfree(struct page *page);
> extern void swap_setup(void);
>
> -extern void lru_cache_add_active_or_unevictable(struct page *page,
> - struct vm_area_struct *vma);
> +extern void __lru_cache_add_active_or_unevictable(struct page *page,
> + unsigned long vma_flags);
> +
> +static inline void lru_cache_add_active_or_unevictable(struct page *page,
> + struct vm_area_struct *vma)
> +{
> + return __lru_cache_add_active_or_unevictable(page, vma->vm_flags);
> +}
>
> /* linux/mm/vmscan.c */
> extern unsigned long zone_reclaimable_pages(struct zone *zone);
> diff --git a/mm/memory.c b/mm/memory.c
> index 56802850e72c..85ec5ce5c0a8 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -2347,7 +2347,7 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf)
> ptep_clear_flush_notify(vma, vmf->address, vmf->pte);
> page_add_new_anon_rmap(new_page, vma, vmf->address, false);
> mem_cgroup_commit_charge(new_page, memcg, false, false);
> - lru_cache_add_active_or_unevictable(new_page, vma);
> + __lru_cache_add_active_or_unevictable(new_page, vmf->vma_flags);
> /*
> * We call the notify macro here because, when using secondary
> * mmu page tables (such as kvm shadow page tables), we want the
> @@ -2896,7 +2896,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
> if (unlikely(page != swapcache && swapcache)) {
> page_add_new_anon_rmap(page, vma, vmf->address, false);
> mem_cgroup_commit_charge(page, memcg, false, false);
> - lru_cache_add_active_or_unevictable(page, vma);
> + __lru_cache_add_active_or_unevictable(page, vmf->vma_flags);
> } else {
> do_page_add_anon_rmap(page, vma, vmf->address, exclusive);
> mem_cgroup_commit_charge(page, memcg, true, false);
> @@ -3048,7 +3048,7 @@ static vm_fault_t do_anonymous_page(struct vm_fault
> *vmf)
> inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES);
> page_add_new_anon_rmap(page, vma, vmf->address, false);
> mem_cgroup_commit_charge(page, memcg, false, false);
> - lru_cache_add_active_or_unevictable(page, vma);
> + __lru_cache_add_active_or_unevictable(page, vmf->vma_flags);
> setpte:
> set_pte_at(vma->vm_mm, vmf->address, vmf->pte, entry);
>
> @@ -3327,7 +3327,7 @@ vm_fault_t alloc_set_pte(struct vm_fault *vmf, struct
> mem_cgroup *memcg,
> inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES);
> page_add_new_anon_rmap(page, vma, vmf->address, false);
> mem_cgroup_commit_charge(page, memcg, false, false);
> - lru_cache_add_active_or_unevictable(page, vma);
> + __lru_cache_add_active_or_unevictable(page, vmf->vma_flags);
> } else {
> inc_mm_counter_fast(vma->vm_mm, mm_counter_file(page));
> page_add_file_rmap(page, false);
> diff --git a/mm/swap.c b/mm/swap.c
> index 3a75722e68a9..a55f0505b563 100644
> --- a/mm/swap.c
> +++ b/mm/swap.c
> @@ -450,12 +450,12 @@ void lru_cache_add(struct page *page)
> * directly back onto it's zone's unevictable list, it does NOT use a
> * per cpu pagevec.
> */
> -void lru_cache_add_active_or_unevictable(struct page *page,
> - struct vm_area_struct *vma)
> +void __lru_cache_add_active_or_unevictable(struct page *page,
> + unsigned long vma_flags)
> {
> VM_BUG_ON_PAGE(PageLRU(page), page);
>
> - if (likely((vma->vm_flags & (VM_LOCKED | VM_SPECIAL)) != VM_LOCKED))
> + if (likely((vma_flags & (VM_LOCKED | VM_SPECIAL)) != VM_LOCKED))
> SetPageActive(page);
> else if (!TestSetPageMlocked(page)) {
> /*
> --
> 2.21.0
>
