ACPICA: Tables: Fix invalid pointer accesses in acpi_tb_parse_root_table().

Linux XSDT validation mechanism backport has introduced a regreession:
  Commit: 671cc68dc61f029d44b43a681356078e02d8dab8
  Subject: ACPICA: Back port and refine validation of the XSDT root table.
There is a pointer still accessed after unmapping.

This patch fixes this issue.  Lv Zheng.

Fixes: 671cc68dc61f (ACPICA: Back port and refine validation of the XSDT root table.)
References: https://bugzilla.kernel.org/show_bug.cgi?id=73911
References: https://bugs.archlinux.org/task/39811
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Reported-and-tested-by: Bruce Chiarelli <mano155@gmail.com>
Reported-and-tested-by: Spyros Stathopoulos <spystath@gmail.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Cc: 3.14+ <stable@vger.kernel.org> # 3.14+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/acpi/acpica/tbutils.c b/drivers/acpi/acpica/tbutils.c
index a4702eee91a820d131960754c14da6aa62f50939..9fb85f38de90e3b073635ef2b854895b13e7b5b8 100644 (file)
--- a/drivers/acpi/acpica/tbutils.c
+++ b/drivers/acpi/acpica/tbutils.c
@@ -461,6 +461,7 @@ acpi_status __init acpi_tb_parse_root_table(acpi_physical_address rsdp_address)
        u32 table_count;
        struct acpi_table_header *table;
        acpi_physical_address address;
+       acpi_physical_address rsdt_address;
        u32 length;
        u8 *table_entry;
        acpi_status status;
@@ -488,11 +489,14 @@ acpi_status __init acpi_tb_parse_root_table(acpi_physical_address rsdp_address)
                 * as per the ACPI specification.
                 */
                address = (acpi_physical_address) rsdp->xsdt_physical_address;
+               rsdt_address =
+                   (acpi_physical_address) rsdp->rsdt_physical_address;
                table_entry_size = ACPI_XSDT_ENTRY_SIZE;
        } else {
                /* Root table is an RSDT (32-bit physical addresses) */
 
                address = (acpi_physical_address) rsdp->rsdt_physical_address;
+               rsdt_address = address;
                table_entry_size = ACPI_RSDT_ENTRY_SIZE;
        }
 
@@ -515,8 +519,7 @@ acpi_status __init acpi_tb_parse_root_table(acpi_physical_address rsdp_address)
 
                        /* Fall back to the RSDT */
 
-                       address =
-                           (acpi_physical_address) rsdp->rsdt_physical_address;
+                       address = rsdt_address;
                        table_entry_size = ACPI_RSDT_ENTRY_SIZE;
                }
        }