The patch titled
Subject: mm: memcontrol: rewrite uncharge API fix - double migration
has been added to the -mm tree. Its filename is
mm-memcontrol-rewrite-uncharge-api-fix-double-migration-v2.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-memcontrol-rewrite-uncharge-api-fix-double-migration-v2.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-memcontrol-rewrite-uncharge-api-fix-double-migration-v2.patch
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------------------------------------------------------
From: Johannes Weiner <hannes@xxxxxxxxxxx>
Subject: mm: memcontrol: rewrite uncharge API fix - double migration
Hugh reports:
VM_BUG_ON_PAGE(!(pc->flags & PCG_MEM))
mm/memcontrol.c:6680!
page had count 1 mapcount 0 mapping anon index 0x196
flags locked uptodate reclaim swapbacked, pcflags 1, memcg not root
mem_cgroup_migrate < move_to_new_page < migrate_pages < compact_zone <
compact_zone_order < try_to_compact_pages < __alloc_pages_direct_compact <
__alloc_pages_nodemask < alloc_pages_vma < do_huge_pmd_anonymous_page <
handle_mm_fault < __do_page_fault
mem_cgroup_migrate() assumes that a page is only migrated once and
then freed immediately after.
However, putting the page back on the LRU list and dropping the
isolation refcount is not done atomically. This allows a PFN-based
migrator like compaction to isolate the page, see the expected
anonymous page refcount of 1, and migrate the page once more.
Properly uncharge the page after it's been migrated, including the
clearing of PCG_USED, so that a subsequent charge migration attempt
will be able to detect it and bail out.
Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Reported-by: Hugh Dickins <hughd@xxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff -puN mm/memcontrol.c~mm-memcontrol-rewrite-uncharge-api-fix-double-migration-v2 mm/memcontrol.c
--- a/mm/memcontrol.c~mm-memcontrol-rewrite-uncharge-api-fix-double-migration-v2
+++ a/mm/memcontrol.c
@@ -6604,7 +6604,6 @@ void mem_cgroup_migrate(struct page *old
VM_BUG_ON_PAGE(!(pc->flags & PCG_MEM), oldpage);
VM_BUG_ON_PAGE(do_swap_account && !(pc->flags & PCG_MEMSW), oldpage);
- pc->flags &= ~(PCG_MEM | PCG_MEMSW);
if (PageTransHuge(oldpage)) {
nr_pages <<= compound_order(oldpage);
@@ -6612,6 +6611,13 @@ void mem_cgroup_migrate(struct page *old
VM_BUG_ON_PAGE(!PageTransHuge(newpage), newpage);
}
+ pc->flags = 0;
+
+ local_irq_disable();
+ mem_cgroup_charge_statistics(pc->mem_cgroup, oldpage, -nr_pages);
+ memcg_check_events(pc->mem_cgroup, oldpage);
+ local_irq_enable();
+
commit_charge(newpage, pc->mem_cgroup, nr_pages, lrucare);
}
_
Patches currently in -mm which might be from hannes@xxxxxxxxxxx are
shmem-fix-faulting-into-a-hole-not-taking-i_mutex.patch
shmem-fix-splicing-from-a-hole-while-its-punched.patch
mm-page-writebackc-fix-divide-by-zero-in-bdi_dirty_limits.patch
vmalloc-use-rcu-list-iterator-to-reduce-vmap_area_lock-contention.patch
mm-page-flags-clean-up-the-page-flag-test-set-clear-macros.patch
mm-memcontrol-fold-mem_cgroup_do_charge.patch
mm-memcontrol-rearrange-charging-fast-path.patch
mm-memcontrol-reclaim-at-least-once-for-__gfp_noretry.patch
mm-huge_memory-use-gfp_transhuge-when-charging-huge-pages.patch
mm-memcontrol-retry-reclaim-for-oom-disabled-and-__gfp_nofail-charges.patch
mm-memcontrol-remove-explicit-oom-parameter-in-charge-path.patch
mm-memcontrol-simplify-move-precharge-function.patch
mm-memcontrol-catch-root-bypass-in-move-precharge.patch
mm-memcontrol-use-root_mem_cgroup-res_counter.patch
mm-memcontrol-remove-ordering-between-pc-mem_cgroup-and-pagecgroupused.patch
mm-memcontrol-do-not-acquire-page_cgroup-lock-for-kmem-pages.patch
mm-memcontrol-rewrite-charge-api.patch
mm-memcontrol-rewrite-charge-api-fix-3.patch
mm-memcontrol-rewrite-uncharge-api.patch
mm-memcontrol-rewrite-uncharge-api-fix-2.patch
mm-memcontrol-rewrite-uncharge-api-fix-4.patch
mm-memcontrol-rewrite-uncharge-api-fix-5.patch
mm-memcontrol-rewrite-charge-api-fix-shmem_unuse.patch
mm-memcontrol-rewrite-uncharge-api-fix-uncharge-from-irq-context.patch
mm-memcontrol-rewrite-uncharge-api-fix-double-migration-v2.patch
mm-memcontrol-rewrite-uncharge-api-fix-double-migration.patch
mm-memcontrol-rewrite-uncharge-api-fix-migrate-before-re-mapping.patch
mm-memcontrol-use-page-lists-for-uncharge-batching.patch
mm-memcontrol-use-page-lists-for-uncharge-batching-fix-hugetlb-page-lru.patch
page-cgroup-trivial-cleanup.patch
page-cgroup-get-rid-of-nr_pcg_flags.patch
memcg-remove-lookup_cgroup_page-prototype.patch
mm-vmscan-remove-remains-of-kswapd-managed-zone-all_unreclaimable.patch
mm-vmscan-rework-compaction-ready-signaling-in-direct-reclaim.patch
mm-vmscan-rework-compaction-ready-signaling-in-direct-reclaim-fix.patch
mm-vmscan-remove-all_unreclaimable.patch
mm-vmscan-remove-all_unreclaimable-fix.patch
mm-vmscan-move-swappiness-out-of-scan_control.patch
mm-vmscan-clean-up-struct-scan_control-v2.patch
mm-export-nr_shmem-via-sysinfo2-si_meminfo-interfaces.patch
mm-replace-init_page_accessed-by-__setpagereferenced.patch
mm-update-the-description-for-vm_total_pages.patch
mm-vmscan-report-the-number-of-file-anon-pages-respectively.patch
mm-pagemap-avoid-unnecessary-overhead-when-tracepoints-are-deactivated.patch
mm-rearrange-zone-fields-into-read-only-page-alloc-statistics-and-page-reclaim-lines.patch
mm-move-zone-pages_scanned-into-a-vmstat-counter.patch
mm-vmscan-only-update-per-cpu-thresholds-for-online-cpu.patch
mm-page_alloc-abort-fair-zone-allocation-policy-when-remotes-nodes-are-encountered.patch
mm-page_alloc-reduce-cost-of-the-fair-zone-allocation-policy.patch
mm-writeback-prevent-race-when-calculating-dirty-limits.patch
nilfs2-integrate-sysfs-support-into-driver-fix.patch
linux-next.patch
debugging-keep-track-of-page-owners.patch
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