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.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/mm-memcontrol-rewrite-uncharge-api-fix-double-migration.patch and later at http://ozlabs.org/~akpm/mmotm/broken-out/mm-memcontrol-rewrite-uncharge-api-fix-double-migration.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ 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. Catch pages that have already been migrated and abort migration gracefully. Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx> Reported-by: Hugh Dickins <hughd@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/memcontrol.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff -puN mm/memcontrol.c~mm-memcontrol-rewrite-uncharge-api-fix-double-migration mm/memcontrol.c --- a/mm/memcontrol.c~mm-memcontrol-rewrite-uncharge-api-fix-double-migration +++ a/mm/memcontrol.c @@ -6653,7 +6653,10 @@ void mem_cgroup_migrate(struct page *old if (!PageCgroupUsed(pc)) return; - VM_BUG_ON_PAGE(!(pc->flags & PCG_MEM), oldpage); + /* Already migrated */ + if (!(pc->flags & PCG_MEM)) + return; + VM_BUG_ON_PAGE(do_swap_account && !(pc->flags & PCG_MEMSW), oldpage); pc->flags &= ~(PCG_MEM | PCG_MEMSW); _ Patches currently in -mm which might be from hannes@xxxxxxxxxxx are memcg-cleanup-memcg_cache_params-refcnt-usage.patch memcg-destroy-kmem-caches-when-last-slab-is-freed.patch memcg-mark-caches-that-belong-to-offline-memcgs-as-dead.patch slub-dont-fail-kmem_cache_shrink-if-slab-placement-optimization-fails.patch slub-make-slab_free-non-preemptable.patch memcg-wait-for-kfrees-to-finish-before-destroying-cache.patch slub-make-dead-memcg-caches-discard-free-slabs-immediately.patch slub-kmem_cache_shrink-check-if-partial-list-is-empty-under-list_lock.patch slab-do-not-keep-free-objects-slabs-on-dead-memcg-caches.patch slab-set-free_limit-for-dead-caches-to-0.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.patch mm-memcontrol-rewrite-uncharge-api-fix-migrate-before-re-mapping.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-remove-all_unreclaimable.patch mm-vmscan-move-swappiness-out-of-scan_control.patch mm-export-nr_shmem-via-sysinfo2-si_meminfo-interfaces.patch mm-replace-init_page_accessed-by-__setpagereferenced.patch mm-zbud-zbud_alloc-minor-param-change.patch mm-zbud-change-zbud_alloc-size-type-to-size_t.patch mm-zpool-implement-common-zpool-api-to-zbud-zsmalloc.patch mm-zpool-zbud-zsmalloc-implement-zpool.patch mm-zpool-update-zswap-to-use-zpool.patch mm-zpool-prevent-zbud-zsmalloc-from-unloading-when-used.patch nilfs2-integrate-sysfs-support-into-driver-fix.patch memcg-deprecate-memoryforce_empty-knob.patch memcg-deprecate-memoryforce_empty-knob-fix.patch debugging-keep-track-of-page-owners.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html