From: Lv Zheng Date: Tue, 5 Jul 2016 05:53:12 +0000 (+0800) Subject: ACPICA: Namespace: Fix namespace/interpreter lock ordering X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=45209046c47b;p=openwrt%2Fstaging%2Fblogic.git 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 Signed-off-by: Rafael J. Wysocki --- 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); }