[PATCH v3 5/6] ACPI: Remove side effect of partly creating a node in acpi_get_node

Jonathan Cameron
2020-08-18T14:27:40Z

acpi_get_node calls acpi_get_pxm to evaluate the _PXM AML method for
entries found in DSDT/SSDT. ACPI 6.3 sec 6.2.14 states
"_PXM evaluates to an integer that identifies a device as belonging to
a Proximity Domain defined in the System Resource Affinity Table (SRAT)."

Hence a _PXM method should not result in creation of a new NUMA node.
Before this patch, _PXM could result in partial instantiation of
NUMA node, missing elements such as zone lists. A call to devm_kzalloc
for example results in a null pointer dereference.

This patch therefore replaces the acpi_map_pxm_to_node with a call
to pxm_to_node.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
Reviewed-by: Barry Song <song.bao.hua@hisilicon.com>
---
drivers/acpi/numa/srat.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/acpi/numa/srat.c b/drivers/acpi/numa/srat.c
index 1fb486f46ee2..2c9a66c203ff 100644
--- a/drivers/acpi/numa/srat.c
+++ b/drivers/acpi/numa/srat.c
@@ -436,6 +436,6 @@ int acpi_get_node(acpi_handle handle)

pxm = acpi_get_pxm(handle);

- return acpi_map_pxm_to_node(pxm);
+ return pxm_to_node(pxm);
}
EXPORT_SYMBOL(acpi_get_node);
--
2.19.1