From: Baolin Wang <baolin.wang@linux.alibaba.com>
To: "Huang, Ying" <ying.huang@intel.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>,
akpm@linux-foundation.org, mike.kravetz@oracle.com,
shy828301@gmail.com, willy@infradead.org, ziy@nvidia.com,
minchan@kernel.org, apopple@nvidia.com,
ave.hansen@linux.intel.com, o451686892@gmail.com,
almasrymina@google.com, jhubbard@nvidia.com,
rcampbell@nvidia.com, peterx@redhat.com, naoya.horiguchi@nec.com,
mhocko@suse.com, riel@redhat.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 14/16] mm/migration: fix potential invalid node access for reclaim-based migration
Date: Mon, 7 Mar 2022 15:04:52 +0800 [thread overview]
Message-ID: <0e74a360-6a72-4edf-47bb-8358a3f1d883@linux.alibaba.com> (raw)
In-Reply-To: <87ee3e5opu.fsf@yhuang6-desk2.ccr.corp.intel.com>
On 3/7/2022 1:14 PM, Huang, Ying wrote:
> Baolin Wang <baolin.wang@linux.alibaba.com> writes:
>
>> On 3/4/2022 5:34 PM, Miaohe Lin wrote:
>>> If we failed to setup hotplug state callbacks for mm/demotion:online in
>>> some corner cases, node_demotion will be left uninitialized. Invalid node
>>> might be returned from the next_demotion_node() when doing reclaim-based
>>> migration. Use kcalloc to allocate node_demotion to fix the issue.
>>> Fixes: ac16ec835314 ("mm: migrate: support multiple target nodes
>>> demotion")
>>> Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
>>> ---
>>> mm/migrate.c | 6 +++---
>>> 1 file changed, 3 insertions(+), 3 deletions(-)
>>> diff --git a/mm/migrate.c b/mm/migrate.c
>>> index 279940c0c064..7b1c0b988234 100644
>>> --- a/mm/migrate.c
>>> +++ b/mm/migrate.c
>>> @@ -2516,9 +2516,9 @@ static int __init migrate_on_reclaim_init(void)
>>> {
>>> int ret;
>>> - node_demotion = kmalloc_array(nr_node_ids,
>>> - sizeof(struct demotion_nodes),
>>> - GFP_KERNEL);
>>> + node_demotion = kcalloc(nr_node_ids,
>>> + sizeof(struct demotion_nodes),
>>> + GFP_KERNEL);
>>
>> Nit: not sure if this is worthy of this rare corner case, but I think
>> the target demotion nodes' default value should be NUMA_NO_NODE
>> instead of 0.
>
> The "nr" field of "struct demotion_nodes" should be initialized as 0. I
> think that is checked before "nodes[]" field.
Right, but it will be confusing that if nr = 0, while the nodes[] still
contains valid node id 0. While we are at this, why not initialize the
node_demotion structure with a clear default value? Anyway, no strong
opinion on this :)
next prev parent reply other threads:[~2022-03-07 7:04 UTC|newest]
Thread overview: 73+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-04 9:33 [PATCH 00/16] A few cleanup and fixup patches for migration Miaohe Lin
2022-03-04 9:33 ` [PATCH 01/16] mm/migration: remove unneeded local variable mapping_locked Miaohe Lin
2022-03-04 13:48 ` Muchun Song
2022-03-07 2:00 ` Huang, Ying
2022-03-08 11:41 ` Miaohe Lin
2022-03-04 9:33 ` [PATCH 02/16] mm/migration: remove unneeded out label Miaohe Lin
2022-03-04 12:12 ` Muchun Song
2022-03-07 2:03 ` Huang, Ying
2022-03-08 11:44 ` Miaohe Lin
2022-03-04 9:33 ` [PATCH 03/16] mm/migration: remove unneeded local variable page_lru Miaohe Lin
2022-03-07 10:58 ` Alistair Popple
2022-03-08 11:29 ` Miaohe Lin
2022-03-04 9:33 ` [PATCH 04/16] mm/migration: reduce the rcu lock duration Miaohe Lin
2022-03-04 12:16 ` Muchun Song
2022-03-07 2:32 ` Huang, Ying
2022-03-08 12:09 ` Miaohe Lin
2022-03-09 1:02 ` Huang, Ying
2022-03-09 8:28 ` Miaohe Lin
2022-03-04 9:33 ` [PATCH 05/16] mm/migration: fix the confusing PageTransHuge check Miaohe Lin
2022-03-04 12:20 ` Muchun Song
2022-03-04 9:33 ` [PATCH 06/16] mm/migration: use helper function vma_lookup() in add_page_for_migration Miaohe Lin
2022-03-04 9:34 ` [PATCH 07/16] mm/migration: use helper macro min_t in do_pages_stat Miaohe Lin
2022-03-04 13:51 ` Muchun Song
2022-03-07 1:14 ` Andrew Morton
2022-03-07 11:51 ` Miaohe Lin
2022-03-04 9:34 ` [PATCH 08/16] mm/migration: avoid unneeded nodemask_t initialization Miaohe Lin
2022-03-04 13:57 ` Muchun Song
2022-03-07 2:31 ` Baolin Wang
2022-03-04 9:34 ` [PATCH 09/16] mm/migration: remove some duplicated codes in migrate_pages Miaohe Lin
2022-03-04 15:16 ` Zi Yan
2022-03-07 1:44 ` Baolin Wang
2022-03-04 9:34 ` [PATCH 10/16] mm/migration: remove PG_writeback handle in folio_migrate_flags Miaohe Lin
2022-03-07 1:21 ` Andrew Morton
2022-03-07 12:44 ` Miaohe Lin
2022-03-04 9:34 ` [PATCH 11/16] mm/migration: remove unneeded lock page and PageMovable check Miaohe Lin
2022-03-04 9:34 ` [PATCH 12/16] mm/migration: fix potential page refcounts leak in migrate_pages Miaohe Lin
2022-03-04 15:21 ` Zi Yan
2022-03-07 1:57 ` Baolin Wang
2022-03-07 5:02 ` Huang, Ying
2022-03-07 6:00 ` Baolin Wang
2022-03-07 12:03 ` Miaohe Lin
2022-03-07 12:01 ` Miaohe Lin
2022-03-07 5:01 ` Huang, Ying
2022-03-07 12:11 ` Miaohe Lin
2022-03-04 9:34 ` [PATCH 13/16] mm/migration: return errno when isolate_huge_page failed Miaohe Lin
2022-03-05 2:23 ` Muchun Song
2022-03-07 11:46 ` Miaohe Lin
2022-03-07 2:14 ` Baolin Wang
2022-03-07 12:20 ` Miaohe Lin
2022-03-08 1:32 ` Baolin Wang
2022-03-08 6:34 ` Miaohe Lin
2022-03-07 5:07 ` Huang, Ying
2022-03-08 12:12 ` Miaohe Lin
2022-03-09 1:00 ` Huang, Ying
2022-03-09 8:29 ` Miaohe Lin
2022-03-04 9:34 ` [PATCH 14/16] mm/migration: fix potential invalid node access for reclaim-based migration Miaohe Lin
2022-03-07 2:25 ` Baolin Wang
2022-03-07 5:14 ` Huang, Ying
2022-03-07 7:04 ` Baolin Wang [this message]
2022-03-08 11:46 ` Miaohe Lin
2022-03-07 5:14 ` Huang, Ying
2022-03-04 9:34 ` [PATCH 15/16] mm/migration: fix possible do_pages_stat_array racing with memory offline Miaohe Lin
2022-03-07 5:21 ` Huang, Ying
2022-03-07 7:01 ` Muchun Song
2022-03-07 7:42 ` Huang, Ying
2022-03-08 11:33 ` Miaohe Lin
2022-03-04 9:34 ` [PATCH 16/16] mm/migration: fix potential pte_unmap on an not mapped pte Miaohe Lin
2022-03-07 5:37 ` Huang, Ying
2022-03-08 12:19 ` Miaohe Lin
2022-03-09 0:56 ` Huang, Ying
2022-03-09 8:48 ` Miaohe Lin
2022-03-07 7:35 ` Alistair Popple
2022-03-08 11:55 ` Miaohe Lin
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