The quilt patch titled
Subject: mm/migration: fix possible do_pages_stat_array racing with memory offline
has been removed from the -mm tree. Its filename was
mm-migration-fix-possible-do_pages_stat_array-racing-with-memory-offline.patch
This patch was dropped because it was merged into mm-stable
------------------------------------------------------
From: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Subject: mm/migration: fix possible do_pages_stat_array racing with memory offline
When follow_page peeks a page, the page could be migrated and then be
offlined while it's still being used by the do_pages_stat_array(). Use
FOLL_GET to hold the page refcnt to fix this potential race.
Link: https://lkml.kernel.org/r/20220318111709.60311-12-linmiaohe@xxxxxxxxxx
Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Acked-by: "Huang, Ying" <ying.huang@xxxxxxxxx>
Reviewed-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Cc: Alistair Popple <apopple@xxxxxxxxxx>
Cc: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
Cc: Zi Yan <ziy@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/migrate.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
--- a/mm/migrate.c~mm-migration-fix-possible-do_pages_stat_array-racing-with-memory-offline
+++ a/mm/migrate.c
@@ -1796,13 +1796,18 @@ static void do_pages_stat_array(struct m
goto set_status;
/* FOLL_DUMP to ignore special (like zero) pages */
- page = follow_page(vma, addr, FOLL_DUMP);
+ page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP);
err = PTR_ERR(page);
if (IS_ERR(page))
goto set_status;
- err = page ? page_to_nid(page) : -ENOENT;
+ if (page) {
+ err = page_to_nid(page);
+ put_page(page);
+ } else {
+ err = -ENOENT;
+ }
set_status:
*status = err;
_
Patches currently in -mm which might be from linmiaohe@xxxxxxxxxx are
mm-swapfile-unuse_pte-can-map-random-data-if-swap-read-fails.patch
mm-swapfile-fix-lost-swap-bits-in-unuse_pte.patch
mm-migration-reduce-the-rcu-lock-duration.patch
mm-migration-remove-unneeded-lock-page-and-pagemovable-check.patch
mm-migration-return-errno-when-isolate_huge_page-failed.patch
mm-migration-fix-potential-pte_unmap-on-an-not-mapped-pte.patch
mm-vmscan-take-min_slab_pages-into-account-when-try-to-call-shrink_node.patch
mm-vmscan-add-a-comment-about-madv_free-pages-check-in-folio_check_dirty_writeback.patch
mm-vmscan-introduce-helper-function-reclaim_page_list.patch
mm-vmscan-take-all-base-pages-of-thp-into-account-when-race-with-speculative-reference.patch
mm-vmscan-remove-obsolete-comment-in-kswapd_run.patch
mm-vmscan-use-helper-folio_is_file_lru.patch
mm-vmscan-use-helper-folio_is_file_lru-fix.patch
mm-z3fold-fix-sheduling-while-atomic.patch
mm-z3fold-fix-possible-null-pointer-dereferencing.patch
mm-z3fold-remove-buggy-use-of-stale-list-for-allocation.patch
mm-z3fold-throw-warning-on-failure-of-trylock_page-in-z3fold_alloc.patch
revert-mm-z3foldc-allow-__gfp_highmem-in-z3fold_alloc.patch
mm-z3fold-put-z3fold-page-back-into-unbuddied-list-when-reclaim-or-migration-fails.patch
mm-z3fold-always-clear-page_claimed-under-z3fold-page-lock.patch
mm-z3fold-fix-z3fold_reclaim_page-races-with-z3fold_free.patch
mm-z3fold-fix-z3fold_page_migrate-races-with-z3fold_map.patch
mm-swap-use-helper-is_swap_pte-in-swap_vma_readahead.patch
mm-swap-use-helper-macro-__attr_rw.patch
mm-swap-fold-__swap_info_get-into-its-sole-caller.patch
mm-swap-remove-unneeded-return-value-of-free_swap_slot.patch
mm-swap-print-bad-swap-offset-entry-in-get_swap_device.patch
mm-swap-remove-buggy-cache-nr-check-in-refill_swap_slots_cache.patch
mm-swap-remove-unneeded-p-=-null-check-in-__swap_duplicate.patch
mm-swap-make-page_swapcount-and-__lru_add_drain_all.patch
mm-swap-avoid-calling-swp_swap_info-when-try-to-check-swp_stable_writes.patch
mm-swap-add-helper-swap_offset_available.patch
mm-swap-fix-the-obsolete-comment-for-swp_type_shift.patch
mm-swap-clean-up-the-comment-of-find_next_to_unuse.patch
mm-swap-fix-the-comment-of-get_kernel_pages.patch
mm-swap-fix-comment-about-swap-extent.patch
