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From: Andrew Morton <akpm@linux-foundation.org>
To: akpm@linux-foundation.org, alex.shi@linux.alibaba.com,
	hannes@cmpxchg.org, hughd@google.com, linux-mm@kvack.org,
	mhocko@suse.com, mm-commits@vger.kernel.org, shakeelb@google.com,
	stable@vger.kernel.org, torvalds@linux-foundation.org
Subject: [patch 06/15] mm/memcg: fix refcount error while moving and swapping
Date: Thu, 23 Jul 2020 21:15:24 -0700
Message-ID: <20200724041524.eAqB5zPs6%akpm@linux-foundation.org> (raw)
In-Reply-To: <20200723211432.b31831a0df3bc2cbdae31b40@linux-foundation.org>

From: Hugh Dickins <hughd@google.com>
Subject: mm/memcg: fix refcount error while moving and swapping

It was hard to keep a test running, moving tasks between memcgs with
move_charge_at_immigrate, while swapping: mem_cgroup_id_get_many()'s
refcount is discovered to be 0 (supposedly impossible), so it is then
forced to REFCOUNT_SATURATED, and after thousands of warnings in quick
succession, the test is at last put out of misery by being OOM killed.

This is because of the way moved_swap accounting was saved up until the
task move gets completed in __mem_cgroup_clear_mc(), deferred from when
mem_cgroup_move_swap_account() actually exchanged old and new ids. 
Concurrent activity can free up swap quicker than the task is scanned,
bringing id refcount down 0 (which should only be possible when
offlining).

Just skip that optimization: do that part of the accounting immediately.

Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2007071431050.4726@eggly.anvils
Fixes: 615d66c37c75 ("mm: memcontrol: fix memcg id ref counter on swap charge move")
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/memcontrol.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/mm/memcontrol.c~mm-memcg-fix-refcount-error-while-moving-and-swapping
+++ a/mm/memcontrol.c
@@ -5669,7 +5669,6 @@ static void __mem_cgroup_clear_mc(void)
 		if (!mem_cgroup_is_root(mc.to))
 			page_counter_uncharge(&mc.to->memory, mc.moved_swap);
 
-		mem_cgroup_id_get_many(mc.to, mc.moved_swap);
 		css_put_many(&mc.to->css, mc.moved_swap);
 
 		mc.moved_swap = 0;
@@ -5860,7 +5859,8 @@ put:			/* get_mctgt_type() gets the page
 			ent = target.ent;
 			if (!mem_cgroup_move_swap_account(ent, mc.from, mc.to)) {
 				mc.precharge--;
-				/* we fixup refcnts and charges later. */
+				mem_cgroup_id_get_many(mc.to, 1);
+				/* we fixup other refcnts and charges later. */
 				mc.moved_swap++;
 			}
 			break;
_

  parent reply index

Thread overview: 86+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-24  4:14 incoming Andrew Morton
2020-07-24  4:15 ` [patch 01/15] mm/memory.c: avoid access flag update TLB flush for retried page fault Andrew Morton
     [not found]   ` <30cf7356-bef1-c621-60cb-e12a8bd9111d@linux.alibaba.com>
2020-07-24  4:56     ` Andrew Morton
2020-07-24  4:15 ` [patch 02/15] mm/mmap.c: close race between munmap() and expand_upwards()/downwards() Andrew Morton
2020-07-24  4:15 ` [patch 03/15] vfs/xattr: mm/shmem: kernfs: release simple xattr entry in a right way Andrew Morton
2020-07-24  4:15 ` [patch 04/15] mm: initialize return of vm_insert_pages Andrew Morton
2020-07-24  4:15 ` [patch 05/15] mm/memcontrol: fix OOPS inside mem_cgroup_get_nr_swap_pages() Andrew Morton
2020-07-24  4:15 ` Andrew Morton [this message]
2020-07-24  4:15 ` [patch 07/15] mm: memcg/slab: fix memory leak at non-root kmem_cache destroy Andrew Morton
2020-07-24  4:15 ` [patch 08/15] mm/hugetlb: avoid hardcoding while checking if cma is enabled Andrew Morton
2020-07-24  4:15 ` [patch 09/15] khugepaged: fix null-pointer dereference due to race Andrew Morton
2020-07-24  4:15 ` [patch 10/15] mailmap: add entry for Mike Rapoport Andrew Morton
2020-07-24  4:15 ` [patch 11/15] squashfs: fix length field overlap check in metadata reading Andrew Morton
2020-07-24  4:15 ` [patch 12/15] scripts/decode_stacktrace: strip basepath from all paths Andrew Morton
2020-07-24  4:15 ` [patch 13/15] io-mapping: indicate mapping failure Andrew Morton
2020-07-24  4:15 ` [patch 14/15] MAINTAINERS: add KCOV section Andrew Morton
2020-07-24  4:15 ` [patch 15/15] scripts/gdb: fix lx-symbols 'gdb.error' while loading modules Andrew Morton
2020-07-27 19:47 ` + mm-remove-unnecessary-wrapper-function-do_mmap_pgoff.patch added to -mm tree Andrew Morton
2020-07-27 19:56 ` + nilfs2-only-call-unlock_new_inode-if-i_new.patch " Andrew Morton
2020-07-27 19:57 ` + nilfs2-convert-__nilfs_msg-to-integrate-the-level-and-format.patch " Andrew Morton
2020-07-27 19:57 ` + nilfs2-use-a-more-common-logging-style.patch " Andrew Morton
2020-07-27 19:58 ` + checkpatch-add-test-for-repeated-words.patch " Andrew Morton
2020-07-27 20:05 ` + ocfs2-replace-http-links-with-https-ones.patch " Andrew Morton
2020-07-27 20:09 ` + ocfs2-fix-unbalanced-locking.patch " Andrew Morton
2020-07-27 20:10 ` + kernelh-remove-duplicate-include-of-asm-div64h.patch " Andrew Morton
2020-07-27 20:11 ` + tools-replace-http-links-with-https-ones.patch " Andrew Morton
2020-07-27 20:12 ` + lib-replace-http-links-with-https-ones.patch " Andrew Morton
2020-07-27 20:12 ` + include-replace-http-links-with-https-ones.patch " Andrew Morton
2020-07-27 20:34 ` + mm-make-mm-locked_vm-an-atomic64-counter.patch " Andrew Morton
2020-07-27 20:34 ` + mm-util-account_locked_vm-does-not-hold-mmap_lock.patch " Andrew Morton
2020-07-27 20:37 ` + cg_read_strcmp-fix-null-pointer-dereference.patch " Andrew Morton
2020-07-27 20:51 ` + mm-hugetlb-add-mempolicy-check-in-the-reservation-routine.patch " Andrew Morton
2020-07-27 20:52 ` [withdrawn] checkpatch-support-deprecated-terms-checking.patch removed from " Andrew Morton
2020-07-27 23:47 ` [obsolete] scripts-deprecated_terms-recommend-denylist-allowlist-instead-of-blacklist-whitelist.patch " Andrew Morton
2020-07-27 23:50 ` [obsolete] scripts-deprecated_terms-sync-with-inclusive-terms.patch " Andrew Morton
2020-07-28  0:18 ` [failures] mm-hugetlb-add-mempolicy-check-in-the-reservation-routine.patch " Andrew Morton
2020-07-28  1:19 ` mmotm 2020-07-27-18-18 uploaded Andrew Morton
     [not found]   ` <ae87385b-f830-dbdf-ebc7-1afb82a7fed0@infradead.org>
2020-07-28 21:55     ` mmotm 2020-07-27-18-18 uploaded (mm/page_alloc.c) Andrew Morton
     [not found]       ` <20200729082053.6c2fb654@canb.auug.org.au>
2020-07-28 22:31         ` Andrew Morton
     [not found]       ` <048cef07-ad4b-8788-94a4-e144de731ab6@infradead.org>
2020-07-29  1:44         ` Andrew Morton
2020-07-28 20:53 ` + mm-mempolicy-fix-kerneldoc-of-numa_map_to_online_node.patch added to -mm tree Andrew Morton
2020-07-28 20:53 ` + mm-mmu_notifier-fix-and-extend-kerneldoc.patch " Andrew Morton
2020-07-28 20:54 ` + mm-swap-fix-kerneldoc-of-swap_vma_readahead.patch " Andrew Morton
2020-07-28 20:58 ` + mm-memcontrol-dont-count-limit-setting-reclaim-as-memory-pressure.patch " Andrew Morton
2020-07-28 21:01 ` + mm-memcontrol-restore-proper-dirty-throttling-when-memoryhigh-changes.patch " Andrew Morton
2020-07-28 22:06 ` + mm-compaction-correct-the-comments-of-compact_defer_shift.patch " Andrew Morton
2020-07-28 22:09 ` + selftests-add-mincore-tests.patch " Andrew Morton
2020-07-28 22:16 ` + proc-pid-smaps-consistent-whitespace-output-format.patch " Andrew Morton
2020-07-28 22:21 ` + xtensa-switch-to-generic-version-of-pte-allocation-fix.patch " Andrew Morton
2020-07-28 22:21 ` Andrew Morton
2020-07-29 21:49 ` + mm-slab-avoid-the-use-of-one-element-array-and-use-struct_size-helper.patch " Andrew Morton
2020-07-29 23:52 ` [obsolete] mm-slab-avoid-the-use-of-one-element-array-and-use-struct_size-helper.patch removed from " Andrew Morton
2020-07-31 19:24 ` + kasan-dont-tag-stacks-allocated-with-pagealloc.patch added to " Andrew Morton
2020-07-31 19:24 ` + kasan-arm64-dont-instrument-functions-that-enable-kasan.patch " Andrew Morton
2020-07-31 19:24 ` + kasan-allow-enabling-stack-tagging-for-tag-based-mode.patch " Andrew Morton
2020-07-31 19:24 ` + kasan-adjust-kasan_stack_oob-for-tag-based-mode.patch " Andrew Morton
2020-07-31 20:00 ` [obsolete] mmhwpoison-rework-soft-offline-for-in-use-pages-fix.patch removed from " Andrew Morton
2020-07-31 20:05 ` + mmhwpoison-cleanup-unused-pagehuge-check.patch added to " Andrew Morton
2020-07-31 20:05 ` + mm-hwpoison-remove-recalculating-hpage.patch " Andrew Morton
2020-07-31 20:05 ` + mmmadvise-call-soft_offline_page-without-mf_count_increased.patch " Andrew Morton
2020-07-31 20:05 ` + mmmadvise-refactor-madvise_inject_error.patch " Andrew Morton
2020-07-31 20:05 ` + mmhwpoison-inject-dont-pin-for-hwpoison_filter.patch " Andrew Morton
2020-07-31 20:05 ` + mmhwpoison-un-export-get_hwpoison_page-and-make-it-static.patch " Andrew Morton
2020-07-31 20:05 ` + mmhwpoison-kill-put_hwpoison_page.patch " Andrew Morton
2020-07-31 20:06 ` + mmhwpoison-remove-mf_count_increased.patch " Andrew Morton
2020-07-31 20:06 ` + mmhwpoison-remove-flag-argument-from-soft-offline-functions.patch " Andrew Morton
2020-07-31 20:06 ` + mmhwpoison-unify-thp-handling-for-hard-and-soft-offline.patch " Andrew Morton
2020-07-31 20:06 ` + mmhwpoison-rework-soft-offline-for-free-pages.patch " Andrew Morton
2020-07-31 20:06 ` + mmhwpoison-rework-soft-offline-for-in-use-pages.patch " Andrew Morton
2020-07-31 20:06 ` + mmhwpoison-refactor-soft_offline_huge_page-and-__soft_offline_page.patch " Andrew Morton
2020-07-31 20:06 ` + mmhwpoison-return-0-if-the-page-is-already-poisoned-in-soft-offline.patch " Andrew Morton
2020-07-31 20:06 ` + mmhwpoison-introduce-mf_msg_unsplit_thp.patch " Andrew Morton
2020-07-31 20:06 ` + mmhwpoison-double-check-page-count-in-__get_any_page.patch " Andrew Morton
2020-07-31 20:23 ` + mm-gup-restrict-cma-region-by-using-allocation-scope-api.patch " Andrew Morton
2020-07-31 20:23 ` + mm-hugetlb-make-hugetlb-migration-callback-cma-aware.patch " Andrew Morton
2020-07-31 20:23 ` + mm-gup-use-a-standard-migration-target-allocation-callback.patch " Andrew Morton
2020-07-31 20:25 ` + mm-migrate-make-a-standard-migration-target-allocation-function-fix.patch " Andrew Morton
2020-07-31 20:26 ` + mm-memcontrol-decouple-reference-counting-from-page-accounting-fix.patch " Andrew Morton
2020-07-31 20:32 ` + mm-dmapoolc-add-warn_on-in-dma_pool_destroy.patch " Andrew Morton
2020-07-31 20:49 ` + kstrto-correct-documentation-references-to-simple_strto.patch " Andrew Morton
2020-07-31 20:49 ` + kstrto-do-not-describe-simple_strto-as-obsolete-replaced.patch " Andrew Morton
2020-07-31 20:57 ` + mm-hugetlb-fix-calculation-of-adjust_range_if_pmd_sharing_possible.patch " Andrew Morton
2020-07-31 20:59 ` + poison-remove-obsolete-comment.patch " Andrew Morton
2020-07-31 21:02 ` + cma-dont-quit-at-first-error-when-activating-reserved-areas.patch " Andrew Morton
2020-07-31 21:10 ` [nacked] mm-dmapoolc-add-warn_on-in-dma_pool_destroy.patch removed from " Andrew Morton
2020-07-31 23:46 ` mmotm 2020-07-31-16-45 uploaded Andrew Morton

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