[PATCH v4 1/5] ACPICA: Namespace: Fix a regression that MLC support triggers dead lock in dynamic table loading

From: Lv Zheng
Date: Tue Jun 21 2016 - 00:34:42 EST


The new MLC approach invokes MLC per-table basis. But the dynamic loading
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
which, the interpreter lock should be locked by acpi_ns_parse_table() but
wasn't. Reported by Mika Westerberg. Fixed by Lv Zheng.

Fixes: 2785ce8d0da1 ("ACPICA: Add per-table execution of module-level code")
Cc: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
Reported-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
Signed-off-by: Lv Zheng <lv.zheng@xxxxxxxxx>
---
drivers/acpi/acpica/exconfig.c | 2 ++
drivers/acpi/acpica/nsparse.c | 9 +++++++--
2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/acpi/acpica/exconfig.c b/drivers/acpi/acpica/exconfig.c
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..1783cd7 100644
--- a/drivers/acpi/acpica/nsparse.c
+++ b/drivers/acpi/acpica/nsparse.c
@@ -47,6 +47,7 @@
#include "acparser.h"
#include "acdispat.h"
#include "actables.h"
+#include "acinterp.h"

#define _COMPONENT ACPI_NAMESPACE
ACPI_MODULE_NAME("nsparse")
@@ -170,6 +171,8 @@ acpi_ns_parse_table(u32 table_index, struct acpi_namespace_node *start_node)

ACPI_FUNCTION_TRACE(ns_parse_table);

+ acpi_ex_enter_interpreter();
+
/*
* AML Parse, pass 1
*
@@ -185,7 +188,7 @@ acpi_ns_parse_table(u32 table_index, struct acpi_namespace_node *start_node)
status = acpi_ns_one_complete_parse(ACPI_IMODE_LOAD_PASS1,
table_index, start_node);
if (ACPI_FAILURE(status)) {
- return_ACPI_STATUS(status);
+ goto error_exit;
}

/*
@@ -201,8 +204,10 @@ acpi_ns_parse_table(u32 table_index, struct acpi_namespace_node *start_node)
status = acpi_ns_one_complete_parse(ACPI_IMODE_LOAD_PASS2,
table_index, start_node);
if (ACPI_FAILURE(status)) {
- return_ACPI_STATUS(status);
+ goto error_exit;
}

+error_exit:
+ acpi_ex_exit_interpreter();
return_ACPI_STATUS(status);
}
--
1.7.10