[PATCH] ACPICA: Fix memory leak at acpi_ds_create_field()

acpi_ds_create_field() allocates internal_pcc_buffer for operation
regions in the PCC address space.

The function runs once per field, so a second field on the
same region overwrites the pointer and orphans the previous buffer.

The matching ACPI_FREE() in acpi_ut_delete_internal_obj() only ever sees
the last one.

An arm64 platform whose SSDT declares regions with multiple fields each
leaks two buffers at boot, as detected by kmemleak:

  unreferenced object 0xffff000051e65400 (size 192):
    comm "swapper/0", pid 1, jiffies 4294668436
    backtrace (crc 0):
      __kmalloc_noprof
      acpi_ds_create_field
      acpi_ds_load2_end_op
      acpi_ds_exec_end_op
      acpi_ps_parse_loop
      acpi_ps_parse_aml
      acpi_ns_load_table
      acpi_load_tables
      acpi_init

Do not allocate a region if it was previously allocated before,
preserving the current design, but, not leaking memory.

Fixes: 0acf24ad7e10 ("ACPICA: Add support for PCC Opregion special context data")
Signed-off-by: Breno Leitao <[email protected]>
---
 drivers/acpi/acpica/dsfield.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/acpi/acpica/dsfield.c b/drivers/acpi/acpica/dsfield.c
index d7d56cc600d31..f7e503bf57c87 100644
--- a/drivers/acpi/acpica/dsfield.c
+++ b/drivers/acpi/acpica/dsfield.c
@@ -522,7 +522,8 @@ acpi_ds_create_field(union acpi_parse_object *op,
 	}
 
 	if (info.region_node->object->region.space_id ==
-	    ACPI_ADR_SPACE_PLATFORM_COMM) {
+	    ACPI_ADR_SPACE_PLATFORM_COMM &&
+	    !region_node->object->field.internal_pcc_buffer) {
 		region_node->object->field.internal_pcc_buffer =
 		    ACPI_ALLOCATE_ZEROED(info.region_node->object->region.
 					 length);

---
base-commit: 28d012efb4327f9c75d5e042a7c91e9a542efa98
change-id: 20260813-acpica-pcc-field-leak-8f676f55179b

Best regards,
--  
Breno Leitao <[email protected]>