RE: [PATCH v3 1/5] ACPICA: Namespace: Fix a regression that MLC support triggers dead lock in dynamic table loading

Hi, Mika

From: Mika Westerberg [mailto:mika.westerberg@linux.intel.com]
Subject: Re: [PATCH v3 1/5] ACPICA: Namespace: Fix a regression that MLC
support triggers dead lock in dynamic table loading

On Mon, Jun 20, 2016 at 05:07:22PM +0800, Lv Zheng wrote:

quoted

The new MLC approach invokes MLC per-table basis. But the dynamic

loading

quoted

support of this is incorrect because of the lock order:
 acpi_ns_evaluate
   acpi_ex_enter_intperter
     acpi_ns_load_table (triggered by Load opcode)
       acpi_ns_exec_module_code_list
         acpi_ex_enter_intperter
The regression is introduced by the following commit:
  Commit: 2785ce8d0da1cac9d8f78615e116cf929e9a9123
  ACPICA Commit: 071eff738c59eda1792ac24b3b688b61691d7e7c
  Subject: ACPICA: Add per-table execution of module-level code
This patch fixes this regression by unlocking the interpreter lock before
invoking MLC. However the unlocking is done to the

acpi_ns_load_table(), in

quoted

which, the interpreter lock should be locked by acpi_ns_parse_table()

but

quoted

wasn't. Reported by Mika Westerberg. Fixed by Lv Zheng.

Fixes: 2785ce8d0da1 ("ACPICA: Add per-table execution of module-level

code")

quoted

Reported-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Lv Zheng <redacted>
---
 drivers/acpi/acpica/exconfig.c |    2 ++
 drivers/acpi/acpica/nsparse.c  |    8 ++++++--
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/acpi/acpica/exconfig.c

b/drivers/acpi/acpica/exconfig.c

quoted

index a1d177d..21932d6 100644

--- a/drivers/acpi/acpica/exconfig.c
+++ b/drivers/acpi/acpica/exconfig.c

@@ -108,7 +108,9 @@ acpi_ex_add_table(u32 table_index,

 	/* Add the table to the namespace */

+	acpi_ex_exit_interpreter();
 	status = acpi_ns_load_table(table_index, parent_node);
+	acpi_ex_enter_interpreter();
 	if (ACPI_FAILURE(status)) {
 		acpi_ut_remove_reference(obj_desc);
 		*ddb_handle = NULL;

diff --git a/drivers/acpi/acpica/nsparse.c b/drivers/acpi/acpica/nsparse.c
index f631a47..0d29383 100644
--- a/drivers/acpi/acpica/nsparse.c
+++ b/drivers/acpi/acpica/nsparse.c

@@ -170,6 +170,8 @@ acpi_ns_parse_table(u32 table_index, struct

acpi_namespace_node *start_node)

quoted

 	ACPI_FUNCTION_TRACE(ns_parse_table);

+	acpi_ex_enter_interpreter();

I'm getting these:

drivers/acpi/acpica/nsparse.c: In function ‘acpi_ns_parse_table’:
drivers/acpi/acpica/nsparse.c:173:2: error: implicit declaration of function
‘acpi_ex_enter_interpreter’ [-Werror=implicit-function-declaration]
  acpi_ex_enter_interpreter();
  ^
drivers/acpi/acpica/nsparse.c:210:2: error: implicit declaration of function
‘acpi_ex_exit_interpreter’ [-Werror=implicit-function-declaration]
  acpi_ex_exit_interpreter();
  ^
cc1: some warnings being treated as errors

Do I need to have some other patch applied before this?

[Lv Zheng] 
The acinterp.h inclusion is in PATCH 03.
I'll re-send the series with this corrected.

Thanks and best regards
-Lv