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authorLv Zheng <lv.zheng@intel.com>2016-07-05 08:53:12 +0300
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2016-07-05 23:48:44 +0300
commit45209046c47b93fadf26dc59a9da724f387b9cf2 (patch)
tree0eaaaeee0a25b9bb2c86260f6a7ab0fb3fab9099
parent2f38b1b16d9280689e5cfa47a4c50956bf437f0d (diff)
downloadlinux-45209046c47b93fadf26dc59a9da724f387b9cf2.tar.xz
ACPICA: Namespace: Fix namespace/interpreter lock ordering
There is a lock order issue in acpi_load_tables(). The namespace lock is held before holding the interpreter lock. With ACPI_MUTEX_DEBUG enabled in the kernel, this is printed to the log during boot: [ 0.885699] ACPI Error: Invalid acquire order: Thread 405884224 owns [ACPI_MTX_Namespace], wants [ACPI_MTX_Interpreter] (20160422/utmutex-263) [ 0.885881] ACPI Error: Could not acquire AML Interpreter mutex (20160422/exutils-95) [ 0.893846] ACPI Error: Mutex [0x0] is not acquired, cannot release (20160422/utmutex-326) [ 0.894019] ACPI Error: Could not release AML Interpreter mutex (20160422/exutils-133) The issue has been introduced by the following commit: Commit: 2f38b1b16d9280689e5cfa47a4c50956bf437f0d ACPICA Commit: bfe03ffcde8ed56a7eae38ea0b188aeb12f9c52e Subject: ACPICA: Namespace: Fix a regression that MLC support triggers dead lock in dynamic table loading Which fixed a deadlock issue for acpi_ns_load_table() in acpi_ex_add_table() but didn't take care of the lock order in acpi_ns_load_table() correctly. Originally (before the above commit), ACPICA used the namespace/interpreter locks in the following 2 key code paths: 1. Table loading: acpi_ns_load_table L(Namespace) acpi_ns_parse_table acpi_ns_one_complete_parse U(Namespace) 2. Object evaluation: acpi_ns_evaluate L(Interpreter) acpi_ps_execute_method U(Interpreter) acpi_ns_load_table L(Namespace) U(Namespace) acpi_ev_initialize_region L(Namespace) U(Namespace) address_space.setup L(Namespace) U(Namespace) address_space.handler L(Namespace) U(Namespace) acpi_os_wait_semaphore acpi_os_acquire_mutex acpi_os_sleep L(Interpreter) U(Interpreter) During runtime, while acpi_ns_evaluate is called, the lock order is always Interpreter -> Namespace. In turn, the problematic commit acquires the locks in the following order: 3. Table loading: acpi_ns_load_table L(Namespace) acpi_ns_parse_table L(Interpreter) acpi_ns_one_complete_parse U(Interpreter) U(Namespace) To fix the lock order issue, move the interpreter lock to acpi_ns_load_table() to ensure the lock order correctness: 4. Table loading: acpi_ns_load_table L(Interpreter) L(Namespace) acpi_ns_parse_table acpi_ns_one_complete_parse U(Namespace) U(Interpreter) However, this doesn't fix the current design issues related to the namespace lock. For example, we can notice that in acpi_ns_evaluate(), outside of acpi_ns_load_table(), the namespace objects may be created by the named object creation control methods. And the creation of the method-owned namespace objects are not locked by the namespace lock. This patch doesn't try to fix such kind of existing issues. Fixes: 2f38b1b16d92 (ACPICA: Namespace: Fix a regression that MLC support triggers dead lock in dynamic table loading) Signed-off-by: Lv Zheng <lv.zheng@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
-rw-r--r--drivers/acpi/acpica/nsload.c7
-rw-r--r--drivers/acpi/acpica/nsparse.c9
2 files changed, 8 insertions, 8 deletions
diff --git a/drivers/acpi/acpica/nsload.c b/drivers/acpi/acpica/nsload.c
index b5e2b0ada0ab..297f6aacd7d4 100644
--- a/drivers/acpi/acpica/nsload.c
+++ b/drivers/acpi/acpica/nsload.c
@@ -46,6 +46,7 @@
#include "acnamesp.h"
#include "acdispat.h"
#include "actables.h"
+#include "acinterp.h"
#define _COMPONENT ACPI_NAMESPACE
ACPI_MODULE_NAME("nsload")
@@ -78,6 +79,8 @@ acpi_ns_load_table(u32 table_index, struct acpi_namespace_node *node)
ACPI_FUNCTION_TRACE(ns_load_table);
+ acpi_ex_enter_interpreter();
+
/*
* Parse the table and load the namespace with all named
* objects found within. Control methods are NOT parsed
@@ -89,7 +92,7 @@ acpi_ns_load_table(u32 table_index, struct acpi_namespace_node *node)
*/
status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
if (ACPI_FAILURE(status)) {
- return_ACPI_STATUS(status);
+ goto unlock_interp;
}
/* If table already loaded into namespace, just return */
@@ -130,6 +133,8 @@ acpi_ns_load_table(u32 table_index, struct acpi_namespace_node *node)
unlock:
(void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
+unlock_interp:
+ (void)acpi_ex_exit_interpreter();
if (ACPI_FAILURE(status)) {
return_ACPI_STATUS(status);
diff --git a/drivers/acpi/acpica/nsparse.c b/drivers/acpi/acpica/nsparse.c
index 1783cd7e1446..f631a47724f0 100644
--- a/drivers/acpi/acpica/nsparse.c
+++ b/drivers/acpi/acpica/nsparse.c
@@ -47,7 +47,6 @@
#include "acparser.h"
#include "acdispat.h"
#include "actables.h"
-#include "acinterp.h"
#define _COMPONENT ACPI_NAMESPACE
ACPI_MODULE_NAME("nsparse")
@@ -171,8 +170,6 @@ 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
*
@@ -188,7 +185,7 @@ 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)) {
- goto error_exit;
+ return_ACPI_STATUS(status);
}
/*
@@ -204,10 +201,8 @@ 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)) {
- goto error_exit;
+ return_ACPI_STATUS(status);
}
-error_exit:
- acpi_ex_exit_interpreter();
return_ACPI_STATUS(status);
}