Messages in this thread | | | From | "Huang, Ying" <> | Subject | Re: [PATCH 14/16] mm/migration: fix potential invalid node access for reclaim-based migration | Date | Mon, 07 Mar 2022 13:14:05 +0800 |
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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.
Best Regards, Huang, Ying
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