According to Section 6.2.14 from ACPI spec 6.3 [1], the setting
of proximity domain is optional, as below:

This optional object is used to describe proximity domain
associations within a machine. _PXM evaluates to an integer
that identifies a device as belonging to a Proximity Domain
defined in the System Resource Affinity Table (SRAT).

This patch checks node id with the below case before returning
node_to_cpumask_map[node]:
1. if node_id >= nr_node_ids, return cpu_none_mask
2. if node_id < 0, return cpu_online_mask
3. if node_to_cpumask_map[node_id] is NULL, return cpu_online_mask

[1] https://uefi.org/sites/default/files/resources/ACPI_6_3_final_Jan30.pdf

Signed-off-by: Yunsheng Lin <redacted>
---
note node_to_cpumask_map[node] is already a pointer, so the
cpumask_clear should be called with node_to_cpumask_map[node]
instead of &node_to_cpumask_map[node]? And cpumask_of_node()
function need to be inlined when defined in a header file?
If the above are problems, maybe another patch to fix or clean
it up.
---
 arch/alpha/include/asm/topology.h | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/alpha/include/asm/topology.h b/arch/alpha/include/asm/topology.h
index 5a77a40..9e0b1cd1 100644
--- a/arch/alpha/include/asm/topology.h
+++ b/arch/alpha/include/asm/topology.h

@@ -30,8 +30,11 @@ static const struct cpumask *cpumask_of_node(int node)
 {
 	int cpu;
 
-	if (node == NUMA_NO_NODE)
-		return cpu_all_mask;
+	if (node >= nr_node_ids)
+		return cpu_none_mask;
+
+	if (node < 0 || !node_to_cpumask_map[node])
+		return cpu_online_mask;
 
 	cpumask_clear(&node_to_cpumask_map[node]);
 

-- 
2.8.1