Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 500d65d4 authored by Andrea Arcangeli's avatar Andrea Arcangeli Committed by Linus Torvalds
Browse files

thp: pmd_trans_huge migrate bugcheck 



No pmd_trans_huge should ever materialize in migration ptes areas, because
we split the hugepage before migration ptes are instantiated.

Signed-off-by: default avatarAndrea Arcangeli <aarcange@redhat.com>
Acked-by: default avatarRik van Riel <riel@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 0af4e98b

include/linux/mm.h

+1 −0
Original line number Diff line number Diff line
@@ -1490,6 +1490,7 @@ struct page *follow_page(struct vm_area_struct *, unsigned long address, 
#define FOLL_DUMP	0x08	/* give error on hole if it would be zero */

#define FOLL_FORCE	0x10	/* get_user_pages read/write w/o permission */

#define FOLL_MLOCK	0x40	/* mark page as mlocked */

#define FOLL_SPLIT	0x80	/* don't return transhuge pages, split them */



typedef int (*pte_fn_t)(pte_t *pte, pgtable_t token, unsigned long addr,

			void *data);

mm/memory.c

+5 −0
Original line number Diff line number Diff line
@@ -1305,6 +1305,10 @@ struct page *follow_page(struct vm_area_struct *vma, unsigned long address, 
		goto out;

	}

	if (pmd_trans_huge(*pmd)) {

		if (flags & FOLL_SPLIT) {

			split_huge_page_pmd(mm, pmd);

			goto split_fallthrough;

		}

		spin_lock(&mm->page_table_lock);

		if (likely(pmd_trans_huge(*pmd))) {

			if (unlikely(pmd_trans_splitting(*pmd))) {
@@ -1320,6 +1324,7 @@ struct page *follow_page(struct vm_area_struct *vma, unsigned long address, 
			spin_unlock(&mm->page_table_lock);

		/* fall through */

	}

split_fallthrough:

	if (unlikely(pmd_bad(*pmd)))

		goto no_page_table;

mm/migrate.c

+6 −1
Original line number Diff line number Diff line
@@ -113,6 +113,8 @@ static int remove_migration_pte(struct page *new, struct vm_area_struct *vma, 
			goto out;



		pmd = pmd_offset(pud, addr);

		if (pmd_trans_huge(*pmd))

			goto out;

		if (!pmd_present(*pmd))

			goto out;
@@ -632,6 +634,9 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private, 
		/* page was freed from under us. So we are done. */

		goto move_newpage;

	}

	if (unlikely(PageTransHuge(page)))

		if (unlikely(split_huge_page(page)))

			goto move_newpage;



	/* prepare cgroup just returns 0 or -ENOMEM */

	rc = -EAGAIN;
@@ -1063,7 +1068,7 @@ static int do_move_page_to_node_array(struct mm_struct *mm, 
		if (!vma || pp->addr < vma->vm_start || !vma_migratable(vma))

			goto set_status;



		page = follow_page(vma, pp->addr, FOLL_GET);

		page = follow_page(vma, pp->addr, FOLL_GET|FOLL_SPLIT);



		err = PTR_ERR(page);

		if (IS_ERR(page))