There is a hidden logic for acpi_tb_install_standard_table() as it can be
invoked from boot stage and during runtime.
1. When it is invoked from the OS boot stage, ACPICA mutex may not be
available, and thus no acpi_ut_acquire_mutex()/acpi_ut_release_mutex() are
invoked in these code paths:
acpi_initialize_tables
acpi_tb_parse_root_table
acpi_tb_install_standard_table (4 invocations)
acpi_install_table
acpi_tb_install_standard_table
2. When it is invoked during the runtime, ACPICA mutex is correctly used:
acpi_ex_load_op
acpi_tb_install_and_load_table
acpi_tb_install_standard_table
acpi_load_table
acpi_tb_install_and_load_table
acpi_tb_install_standard_table
So the mutex is now used in acpi_tb_install_and_load_table(), while it actually
should be in acpi_tb_install_standard_table().
This introduces another problem in acpi_tb_install_standard_table() where
acpi_gbl_table_handler is invoked from and the lock contexts are thus not
consistent for the table handlers. This triggers a regression when
acpi_get_table()/acpi_put_table() start to hold table mutex during runtime.
The regression is noticed by LKP as new errors reported by ACPICA mutex
debugging facility.
[ 2.043693] ACPI Error: Mutex [ACPI_MTX_Tables] already acquired by this thread [497483776] (20160930/utmutex-254)
[ 2.054084] ACPI Error: Mutex [0x2] is not acquired, cannot release (20160930/utmutex-326)
And it triggers a dead lock:
[ 247.066214] INFO: task swapper/0:1 blocked for more than 120 seconds.
...
[ 247.091271] Call Trace:
...
[ 247.121523] down_timeout+0x47/0x50
[ 247.125065] acpi_os_wait_semaphore+0x47/0x62
[ 247.129475] acpi_ut_acquire_mutex+0x43/0x81
[ 247.133798] acpi_get_table+0x2d/0x84
[ 247.137513] acpi_table_attr_init+0xcd/0x100
[ 247.146590] acpi_sysfs_table_handler+0x5d/0xb8
[ 247.151174] acpi_bus_table_handler+0x23/0x2a
[ 247.155583] acpi_tb_install_standard_table+0xe0/0x213
[ 247.164489] acpi_tb_install_and_load_table+0x3a/0x82
[ 247.169592] acpi_ex_load_op+0x194/0x201
...
[ 247.200108] acpi_ns_evaluate+0x1bb/0x247
[ 247.204170] acpi_evaluate_object+0x178/0x274
[ 247.213249] acpi_processor_set_pdc+0x154/0x17b
...
The table mutex is held in acpi_tb_install_and_load_table() and is re-visited by
acpi_get_table().
Noticing that the early mutex requirement actually belongs to the OSL layer
and has already been handled in Linux
acpi_os_wait_semaphore()/acpi_os_signal_semaphore(). This patch then can
fix the regression by removing this hidden logic from ACPICA core and
leaving it to OSPMs. A documentation update should also be required.
Fixes: 174cc7187e6f ('ACPICA: Tables: Back port acpi_get_table_with_size() and early_acpi_os_unmap_memory() from Linux kernel')
Reported-by: Tomi Sarvela <tomi.p.sarvela@xxxxxxxxx>
Reported-by: Ye Xiaolong <xiaolong.ye@xxxxxxxxx>
Cc: Tomi Sarvela <tomi.p.sarvela@xxxxxxxxx>
Cc: Ye Xiaolong <xiaolong.ye@xxxxxxxxx>
Signed-off-by: Lv Zheng <lv.zheng@xxxxxxxxx>
---
drivers/acpi/acpica/tbdata.c | 9 ++-------
drivers/acpi/acpica/tbinstal.c | 17 +++++++++++++++--
2 files changed, 17 insertions(+), 9 deletions(-)
diff --git a/drivers/acpi/acpica/tbdata.c b/drivers/acpi/acpica/tbdata.c
index 82b0b57..b0399e8 100644
--- a/drivers/acpi/acpica/tbdata.c
+++ b/drivers/acpi/acpica/tbdata.c
@@ -852,23 +852,18 @@ acpi_tb_install_and_load_table(acpi_physical_address address,
ACPI_FUNCTION_TRACE(tb_install_and_load_table);
- (void)acpi_ut_acquire_mutex(ACPI_MTX_TABLES);
-
/* Install the table and load it into the namespace */
status = acpi_tb_install_standard_table(address, flags, TRUE,
override, &i);
if (ACPI_FAILURE(status)) {
- goto unlock_and_exit;
+ goto exit;
}
- (void)acpi_ut_release_mutex(ACPI_MTX_TABLES);
status = acpi_tb_load_table(i, acpi_gbl_root_node);
- (void)acpi_ut_acquire_mutex(ACPI_MTX_TABLES);
-unlock_and_exit:
+exit:
*table_index = i;
- (void)acpi_ut_release_mutex(ACPI_MTX_TABLES);
return_ACPI_STATUS(status);
}
diff --git a/drivers/acpi/acpica/tbinstal.c b/drivers/acpi/acpica/tbinstal.c
index 5fdf251..01e1b3d 100644
--- a/drivers/acpi/acpica/tbinstal.c
+++ b/drivers/acpi/acpica/tbinstal.c
@@ -217,6 +217,10 @@ acpi_tb_install_standard_table(acpi_physical_address address,
goto release_and_exit;
}
+ /* Acquire the table lock */
+
+ (void)acpi_ut_acquire_mutex(ACPI_MTX_TABLES);
+
if (reload) {
/*
* Validate the incoming table signature.
@@ -244,7 +248,7 @@ acpi_tb_install_standard_table(acpi_physical_address address,
new_table_desc.signature.integer));
status = AE_BAD_SIGNATURE;
- goto release_and_exit;
+ goto unlock_and_exit;
}
/* Check if table is already registered */
@@ -279,7 +283,7 @@ acpi_tb_install_standard_table(acpi_physical_address address,
/* Table is still loaded, this is an error */
status = AE_ALREADY_EXISTS;
- goto release_and_exit;
+ goto unlock_and_exit;
} else {
/*
* Table was unloaded, allow it to be reloaded.
@@ -290,6 +294,7 @@ acpi_tb_install_standard_table(acpi_physical_address address,
* indicate the re-installation.
*/
acpi_tb_uninstall_table(&new_table_desc);
+ (void)acpi_ut_release_mutex(ACPI_MTX_TABLES);
*table_index = i;
return_ACPI_STATUS(AE_OK);
}
@@ -303,11 +308,19 @@ acpi_tb_install_standard_table(acpi_physical_address address,
/* Invoke table handler if present */
+ (void)acpi_ut_release_mutex(ACPI_MTX_TABLES);
if (acpi_gbl_table_handler) {
(void)acpi_gbl_table_handler(ACPI_TABLE_EVENT_INSTALL,
new_table_desc.pointer,
acpi_gbl_table_handler_context);
}
+ (void)acpi_ut_acquire_mutex(ACPI_MTX_TABLES);
+
+unlock_and_exit:
+
+ /* Release the table lock */
+
+ (void)acpi_ut_release_mutex(ACPI_MTX_TABLES);
release_and_exit:
--
2.7.4
--
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