ACPICA: Fix AcpiWalkNamespace race condition with table unload
Added a reader/writer locking mechanism to allow multiple concurrent namespace walks (readers), but a dynamic table unload will have exclusive access to the namespace. This fixes a problem where a table unload could delete the portion of the namespace that is currently being examined by a walk. Adds a new file, utlock.c that implements the reader/writer lock mechanism. ACPICA BZ 749. http://www.acpica.org/bugzilla/show_bug.cgi?id=749 Signed-off-by: Bob Moore <robert.moore@intel.com> Signed-off-by: Lin Ming <ming.m.lin@intel.com> Signed-off-by: Len Brown <len.brown@intel.com>
This commit is contained in:
Bob Moore
Len Brown
Родитель
aab61b676a
Коммит
8a335a2331
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@ -41,4 +41,4 @@ obj-y += tbxface.o tbinstal.o tbutils.o tbfind.o tbfadt.o tbxfroot.o
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obj-y += utalloc.o utdebug.o uteval.o utinit.o utmisc.o utxface.o \
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utcopy.o utdelete.o utglobal.o utmath.o utobject.o \
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utstate.o utmutex.o utobject.o utresrc.o
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utstate.o utmutex.o utobject.o utresrc.o utlock.o
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@ -165,6 +165,10 @@ ACPI_EXTERN u8 acpi_gbl_integer_bit_width;
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ACPI_EXTERN u8 acpi_gbl_integer_byte_width;
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ACPI_EXTERN u8 acpi_gbl_integer_nybble_width;
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/* Reader/Writer lock is used for namespace walk and dynamic table unload */
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ACPI_EXTERN struct acpi_rw_lock acpi_gbl_namespace_rw_lock;
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/*****************************************************************************
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*
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* Mutual exlusion within ACPICA subsystem
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@ -108,6 +108,14 @@ static char *acpi_gbl_mutex_names[ACPI_NUM_MUTEX] = {
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#endif
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#endif
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/* Lock structure for reader/writer interfaces */
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struct acpi_rw_lock {
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acpi_mutex writer_mutex;
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acpi_mutex reader_mutex;
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u32 num_readers;
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};
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/*
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* Predefined handles for spinlocks used within the subsystem.
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* These spinlocks are created by acpi_ut_mutex_initialize
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@ -79,7 +79,7 @@ void acpi_tb_delete_table(struct acpi_table_desc *table_desc);
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void acpi_tb_terminate(void);
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void acpi_tb_delete_namespace_by_owner(u32 table_index);
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acpi_status acpi_tb_delete_namespace_by_owner(u32 table_index);
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acpi_status acpi_tb_allocate_owner_id(u32 table_index);
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@ -345,6 +345,21 @@ acpi_ut_execute_UID(struct acpi_namespace_node *device_node,
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acpi_status
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acpi_ut_execute_sxds(struct acpi_namespace_node *device_node, u8 * highest);
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/*
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* utlock - reader/writer locks
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*/
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acpi_status acpi_ut_create_rw_lock(struct acpi_rw_lock *lock);
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void acpi_ut_delete_rw_lock(struct acpi_rw_lock *lock);
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acpi_status acpi_ut_acquire_read_lock(struct acpi_rw_lock *lock);
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acpi_status acpi_ut_release_read_lock(struct acpi_rw_lock *lock);
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acpi_status acpi_ut_acquire_write_lock(struct acpi_rw_lock *lock);
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void acpi_ut_release_write_lock(struct acpi_rw_lock *lock);
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/*
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* utobject - internal object create/delete/cache routines
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*/
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@ -180,11 +180,23 @@ acpi_ds_initialize_objects(u32 table_index,
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/* Walk entire namespace from the supplied root */
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status = acpi_walk_namespace(ACPI_TYPE_ANY, start_node, ACPI_UINT32_MAX,
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acpi_ds_init_one_object, &info, NULL);
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status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
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if (ACPI_FAILURE(status)) {
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return_ACPI_STATUS(status);
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}
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/*
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* We don't use acpi_walk_namespace since we do not want to acquire
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* the namespace reader lock.
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*/
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status =
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acpi_ns_walk_namespace(ACPI_TYPE_ANY, start_node, ACPI_UINT32_MAX,
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ACPI_NS_WALK_UNLOCK, acpi_ds_init_one_object,
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&info, NULL);
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if (ACPI_FAILURE(status)) {
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ACPI_EXCEPTION((AE_INFO, status, "During WalkNamespace"));
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}
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(void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
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status = acpi_get_table_by_index(table_index, &table);
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if (ACPI_FAILURE(status)) {
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@ -520,13 +520,14 @@ acpi_status acpi_ex_unload_table(union acpi_operand_object *ddb_handle)
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}
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}
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/*
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* Delete the entire namespace under this table Node
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* (Offset contains the table_id)
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*/
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acpi_tb_delete_namespace_by_owner(table_index);
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(void)acpi_tb_release_owner_id(table_index);
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/* Delete the portion of the namespace owned by this table */
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status = acpi_tb_delete_namespace_by_owner(table_index);
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if (ACPI_FAILURE(status)) {
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return_ACPI_STATUS(status);
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}
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(void)acpi_tb_release_owner_id(table_index);
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acpi_tb_set_table_loaded_flag(table_index, FALSE);
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/* Table unloaded, remove a reference to the ddb_handle object */
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@ -475,21 +475,40 @@ acpi_walk_namespace(acpi_object_type type,
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}
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/*
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* Lock the namespace around the walk.
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* The namespace will be unlocked/locked around each call
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* to the user function - since this function
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* must be allowed to make Acpi calls itself.
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* Need to acquire the namespace reader lock to prevent interference
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* with any concurrent table unloads (which causes the deletion of
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* namespace objects). We cannot allow the deletion of a namespace node
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* while the user function is using it. The exception to this are the
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* nodes created and deleted during control method execution -- these
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* nodes are marked as temporary nodes and are ignored by the namespace
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* walk. Thus, control methods can be executed while holding the
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* namespace deletion lock (and the user function can execute control
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* methods.)
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*/
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status = acpi_ut_acquire_read_lock(&acpi_gbl_namespace_rw_lock);
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if (ACPI_FAILURE(status)) {
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return status;
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}
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/*
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* Lock the namespace around the walk. The namespace will be
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* unlocked/locked around each call to the user function - since the user
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* function must be allowed to make ACPICA calls itself (for example, it
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* will typically execute control methods during device enumeration.)
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*/
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status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
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if (ACPI_FAILURE(status)) {
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return_ACPI_STATUS(status);
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goto unlock_and_exit;
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}
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status = acpi_ns_walk_namespace(type, start_object, max_depth,
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ACPI_NS_WALK_UNLOCK,
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user_function, context, return_value);
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ACPI_NS_WALK_UNLOCK, user_function,
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context, return_value);
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(void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
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unlock_and_exit:
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(void)acpi_ut_release_read_lock(&acpi_gbl_namespace_rw_lock);
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return_ACPI_STATUS(status);
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}
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@ -434,27 +434,56 @@ void acpi_tb_terminate(void)
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*
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* PARAMETERS: table_index - Table index
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*
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* RETURN: None
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* RETURN: Status
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*
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* DESCRIPTION: Delete all namespace objects created when this table was loaded.
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*
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******************************************************************************/
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void acpi_tb_delete_namespace_by_owner(u32 table_index)
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acpi_status acpi_tb_delete_namespace_by_owner(u32 table_index)
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{
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acpi_owner_id owner_id;
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acpi_status status;
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(void)acpi_ut_acquire_mutex(ACPI_MTX_TABLES);
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if (table_index < acpi_gbl_root_table_list.count) {
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owner_id =
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acpi_gbl_root_table_list.tables[table_index].owner_id;
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} else {
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(void)acpi_ut_release_mutex(ACPI_MTX_TABLES);
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return;
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ACPI_FUNCTION_TRACE(tb_delete_namespace_by_owner);
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status = acpi_ut_acquire_mutex(ACPI_MTX_TABLES);
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if (ACPI_FAILURE(status)) {
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return_ACPI_STATUS(status);
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}
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if (table_index >= acpi_gbl_root_table_list.count) {
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/* The table index does not exist */
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(void)acpi_ut_release_mutex(ACPI_MTX_TABLES);
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return_ACPI_STATUS(AE_NOT_EXIST);
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}
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/* Get the owner ID for this table, used to delete namespace nodes */
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owner_id = acpi_gbl_root_table_list.tables[table_index].owner_id;
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(void)acpi_ut_release_mutex(ACPI_MTX_TABLES);
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/*
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* Need to acquire the namespace writer lock to prevent interference
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* with any concurrent namespace walks. The interpreter must be
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* released during the deletion since the acquisition of the deletion
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* lock may block, and also since the execution of a namespace walk
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* must be allowed to use the interpreter.
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*/
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acpi_ut_release_mutex(ACPI_MTX_INTERPRETER);
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status = acpi_ut_acquire_write_lock(&acpi_gbl_namespace_rw_lock);
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acpi_ns_delete_namespace_by_owner(owner_id);
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if (ACPI_FAILURE(status)) {
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return_ACPI_STATUS(status);
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}
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acpi_ut_release_write_lock(&acpi_gbl_namespace_rw_lock);
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status = acpi_ut_acquire_mutex(ACPI_MTX_INTERPRETER);
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return_ACPI_STATUS(status);
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}
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/*******************************************************************************
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@ -0,0 +1,175 @@
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/******************************************************************************
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*
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* Module Name: utlock - Reader/Writer lock interfaces
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*
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*****************************************************************************/
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/*
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* Copyright (C) 2000 - 2009, Intel Corp.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions, and the following disclaimer,
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* without modification.
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* 2. Redistributions in binary form must reproduce at minimum a disclaimer
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* substantially similar to the "NO WARRANTY" disclaimer below
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* ("Disclaimer") and any redistribution must be conditioned upon
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* including a substantially similar Disclaimer requirement for further
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* binary redistribution.
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* 3. Neither the names of the above-listed copyright holders nor the names
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* of any contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* Alternatively, this software may be distributed under the terms of the
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* GNU General Public License ("GPL") version 2 as published by the Free
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* Software Foundation.
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*
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* NO WARRANTY
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGES.
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*/
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#include <acpi/acpi.h>
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#include "accommon.h"
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#define _COMPONENT ACPI_UTILITIES
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ACPI_MODULE_NAME("utlock")
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/*******************************************************************************
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*
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* FUNCTION: acpi_ut_create_rw_lock
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* acpi_ut_delete_rw_lock
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*
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* PARAMETERS: Lock - Pointer to a valid RW lock
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*
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* RETURN: Status
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*
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* DESCRIPTION: Reader/writer lock creation and deletion interfaces.
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*
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******************************************************************************/
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acpi_status acpi_ut_create_rw_lock(struct acpi_rw_lock *lock)
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{
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acpi_status status;
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lock->num_readers = 0;
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status = acpi_os_create_mutex(&lock->reader_mutex);
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if (ACPI_FAILURE(status)) {
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return status;
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}
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status = acpi_os_create_mutex(&lock->writer_mutex);
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return status;
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}
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void acpi_ut_delete_rw_lock(struct acpi_rw_lock *lock)
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{
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acpi_os_delete_mutex(lock->reader_mutex);
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acpi_os_delete_mutex(lock->writer_mutex);
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lock->num_readers = 0;
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lock->reader_mutex = NULL;
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lock->writer_mutex = NULL;
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}
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/*******************************************************************************
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*
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* FUNCTION: acpi_ut_acquire_read_lock
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* acpi_ut_release_read_lock
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*
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* PARAMETERS: Lock - Pointer to a valid RW lock
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*
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* RETURN: Status
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*
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* DESCRIPTION: Reader interfaces for reader/writer locks. On acquisition,
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* only the first reader acquires the write mutex. On release,
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* only the last reader releases the write mutex. Although this
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* algorithm can in theory starve writers, this should not be a
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* problem with ACPICA since the subsystem is infrequently used
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* in comparison to (for example) an I/O system.
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*
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******************************************************************************/
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acpi_status acpi_ut_acquire_read_lock(struct acpi_rw_lock *lock)
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{
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acpi_status status;
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status = acpi_os_acquire_mutex(lock->reader_mutex, ACPI_WAIT_FOREVER);
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if (ACPI_FAILURE(status)) {
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return status;
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}
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/* Acquire the write lock only for the first reader */
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lock->num_readers++;
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if (lock->num_readers == 1) {
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status =
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acpi_os_acquire_mutex(lock->writer_mutex,
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ACPI_WAIT_FOREVER);
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}
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acpi_os_release_mutex(lock->reader_mutex);
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return status;
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}
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acpi_status acpi_ut_release_read_lock(struct acpi_rw_lock *lock)
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{
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acpi_status status;
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status = acpi_os_acquire_mutex(lock->reader_mutex, ACPI_WAIT_FOREVER);
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if (ACPI_FAILURE(status)) {
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return status;
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}
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/* Release the write lock only for the very last reader */
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lock->num_readers--;
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if (lock->num_readers == 0) {
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acpi_os_release_mutex(lock->writer_mutex);
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}
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acpi_os_release_mutex(lock->reader_mutex);
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return status;
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}
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/*******************************************************************************
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*
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* FUNCTION: acpi_ut_acquire_write_lock
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* acpi_ut_release_write_lock
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*
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* PARAMETERS: Lock - Pointer to a valid RW lock
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*
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* RETURN: Status
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*
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* DESCRIPTION: Writer interfaces for reader/writer locks. Simply acquire or
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* release the writer mutex associated with the lock. Acquisition
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* of the lock is fully exclusive and will block all readers and
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* writers until it is released.
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*
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******************************************************************************/
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acpi_status acpi_ut_acquire_write_lock(struct acpi_rw_lock *lock)
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{
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acpi_status status;
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status = acpi_os_acquire_mutex(lock->writer_mutex, ACPI_WAIT_FOREVER);
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return status;
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}
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void acpi_ut_release_write_lock(struct acpi_rw_lock *lock)
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{
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acpi_os_release_mutex(lock->writer_mutex);
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}
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@ -60,7 +60,8 @@ static acpi_status acpi_ut_delete_mutex(acpi_mutex_handle mutex_id);
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*
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* RETURN: Status
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*
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* DESCRIPTION: Create the system mutex objects.
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* DESCRIPTION: Create the system mutex objects. This includes mutexes,
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* spin locks, and reader/writer locks.
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*
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******************************************************************************/
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@ -71,9 +72,8 @@ acpi_status acpi_ut_mutex_initialize(void)
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ACPI_FUNCTION_TRACE(ut_mutex_initialize);
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/*
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* Create each of the predefined mutex objects
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*/
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/* Create each of the predefined mutex objects */
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for (i = 0; i < ACPI_NUM_MUTEX; i++) {
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status = acpi_ut_create_mutex(i);
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if (ACPI_FAILURE(status)) {
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@ -86,6 +86,9 @@ acpi_status acpi_ut_mutex_initialize(void)
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spin_lock_init(acpi_gbl_gpe_lock);
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spin_lock_init(acpi_gbl_hardware_lock);
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/* Create the reader/writer lock for namespace access */
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status = acpi_ut_create_rw_lock(&acpi_gbl_namespace_rw_lock);
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return_ACPI_STATUS(status);
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}
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@ -97,7 +100,8 @@ acpi_status acpi_ut_mutex_initialize(void)
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*
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* RETURN: None.
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*
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* DESCRIPTION: Delete all of the system mutex objects.
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* DESCRIPTION: Delete all of the system mutex objects. This includes mutexes,
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* spin locks, and reader/writer locks.
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*
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******************************************************************************/
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@ -107,9 +111,8 @@ void acpi_ut_mutex_terminate(void)
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ACPI_FUNCTION_TRACE(ut_mutex_terminate);
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/*
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* Delete each predefined mutex object
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*/
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/* Delete each predefined mutex object */
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for (i = 0; i < ACPI_NUM_MUTEX; i++) {
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(void)acpi_ut_delete_mutex(i);
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}
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@ -118,6 +121,10 @@ void acpi_ut_mutex_terminate(void)
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acpi_os_delete_lock(acpi_gbl_gpe_lock);
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acpi_os_delete_lock(acpi_gbl_hardware_lock);
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/* Delete the reader/writer lock */
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acpi_ut_delete_rw_lock(&acpi_gbl_namespace_rw_lock);
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return_VOID;
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}
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