On 3/7/2022 1:14 PM, Huang, Ying wrote:
Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx> 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@xxxxxxxxxx>
---
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 :)
