[PATCH] ACPI: tables: Fix NULL dereference by acpi_os_map_memory()

[Kiwamu Okabe]

The Infer static analyzer https://fbinfer.com/ reports following
NULL poinster dereference by the acpi_os_map_memory() function.
I believe this patch does fix the issue without any panic.

Signed-off-by: Kiwamu Okabe <okabe@xxxxxxxxxxxxx>
---
 drivers/acpi/tables.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/acpi/tables.c b/drivers/acpi/tables.c
index 8ab0a82b4da4..ae7b7343bacf 100644
--- a/drivers/acpi/tables.c
+++ b/drivers/acpi/tables.c
@@ -717,6 +717,9 @@ acpi_table_initrd_override(struct acpi_table_header *existing_table,
 	while (table_offset + ACPI_HEADER_SIZE <= all_tables_size) {
 		table = acpi_os_map_memory(acpi_tables_addr + table_offset,
 					   ACPI_HEADER_SIZE);
+		if (WARN_ON(!table)) {
+			return AE_OK;
+		}
 		if (table_offset + table->length > all_tables_size) {
 			acpi_os_unmap_memory(table, ACPI_HEADER_SIZE);
 			WARN_ON(1);
@@ -772,6 +775,9 @@ static void __init acpi_table_initrd_scan(void)
 	while (table_offset + ACPI_HEADER_SIZE <= all_tables_size) {
 		table = acpi_os_map_memory(acpi_tables_addr + table_offset,
 					   ACPI_HEADER_SIZE);
+		if (WARN_ON(!table)) {
+			return;
+		}
 		if (table_offset + table->length > all_tables_size) {
 			acpi_os_unmap_memory(table, ACPI_HEADER_SIZE);
 			WARN_ON(1);
-- 
2.39.2