Hi,
The following patches address a few issues and do a few cleanups related to
the handling of the _DEP dependencies list.
Please refer to the patch changelogs for details.
Thanks!
From: Rafael J. Wysocki <[email protected]>
Move the invocation of acpi_attach_data() in acpi_device_add()
into a separate function.
No intentional functional impact.
Signed-off-by: Rafael J. Wysocki <[email protected]>
---
drivers/acpi/scan.c | 31 ++++++++++++++++++++-----------
1 file changed, 20 insertions(+), 11 deletions(-)
Index: linux-pm/drivers/acpi/scan.c
===================================================================
--- linux-pm.orig/drivers/acpi/scan.c
+++ linux-pm/drivers/acpi/scan.c
@@ -640,23 +640,32 @@ static int acpi_device_set_name(struct a
return 0;
}
+static int acpi_tie_acpi_dev(struct acpi_device *adev)
+{
+ acpi_handle handle = adev->handle;
+ acpi_status status;
+
+ if (!handle)
+ return 0;
+
+ status = acpi_attach_data(handle, acpi_scan_drop_device, adev);
+ if (ACPI_FAILURE(status)) {
+ acpi_handle_err(handle, "Unable to attach device data\n");
+ return -ENODEV;
+ }
+
+ return 0;
+}
+
int acpi_device_add(struct acpi_device *device,
void (*release)(struct device *))
{
struct acpi_device_bus_id *acpi_device_bus_id;
int result;
- if (device->handle) {
- acpi_status status;
-
- status = acpi_attach_data(device->handle, acpi_scan_drop_device,
- device);
- if (ACPI_FAILURE(status)) {
- acpi_handle_err(device->handle,
- "Unable to attach device data\n");
- return -ENODEV;
- }
- }
+ result = acpi_tie_acpi_dev(device);
+ if (result)
+ return result;
/*
* Linkage
From: Rafael J. Wysocki <[email protected]>
Make acpi_dev_get_first_consumer_dev_cb() a bit more straightforward
and rewrite the comment in it.
No functional impact.
Signed-off-by: Rafael J. Wysocki <[email protected]>
---
drivers/acpi/scan.c | 13 ++++++-------
1 file changed, 6 insertions(+), 7 deletions(-)
Index: linux-pm/drivers/acpi/scan.c
===================================================================
--- linux-pm.orig/drivers/acpi/scan.c
+++ linux-pm/drivers/acpi/scan.c
@@ -2107,13 +2107,12 @@ static int acpi_dev_get_first_consumer_d
struct acpi_device *adev;
adev = acpi_bus_get_acpi_device(dep->consumer);
- if (!adev)
- /* If we don't find an adev then we want to continue parsing */
- return 0;
-
- *(struct acpi_device **)data = adev;
-
- return 1;
+ if (adev) {
+ *(struct acpi_device **)data = adev;
+ return 1;
+ }
+ /* Continue parsing if the device object is not present. */
+ return 0;
}
static int acpi_scan_clear_dep(struct acpi_dep_data *dep, void *data)
Hi,
On 6/16/21 4:24 PM, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <[email protected]>
>
> Move the invocation of acpi_attach_data() in acpi_device_add()
> into a separate function.
>
> No intentional functional impact.
>
> Signed-off-by: Rafael J. Wysocki <[email protected]>
Thanks, patch looks good to me:
Reviewed-by: Hans de Goede <[email protected]>
Regards,
Hans
> ---
> drivers/acpi/scan.c | 31 ++++++++++++++++++++-----------
> 1 file changed, 20 insertions(+), 11 deletions(-)
>
> Index: linux-pm/drivers/acpi/scan.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/scan.c
> +++ linux-pm/drivers/acpi/scan.c
> @@ -640,23 +640,32 @@ static int acpi_device_set_name(struct a
> return 0;
> }
>
> +static int acpi_tie_acpi_dev(struct acpi_device *adev)
> +{
> + acpi_handle handle = adev->handle;
> + acpi_status status;
> +
> + if (!handle)
> + return 0;
> +
> + status = acpi_attach_data(handle, acpi_scan_drop_device, adev);
> + if (ACPI_FAILURE(status)) {
> + acpi_handle_err(handle, "Unable to attach device data\n");
> + return -ENODEV;
> + }
> +
> + return 0;
> +}
> +
> int acpi_device_add(struct acpi_device *device,
> void (*release)(struct device *))
> {
> struct acpi_device_bus_id *acpi_device_bus_id;
> int result;
>
> - if (device->handle) {
> - acpi_status status;
> -
> - status = acpi_attach_data(device->handle, acpi_scan_drop_device,
> - device);
> - if (ACPI_FAILURE(status)) {
> - acpi_handle_err(device->handle,
> - "Unable to attach device data\n");
> - return -ENODEV;
> - }
> - }
> + result = acpi_tie_acpi_dev(device);
> + if (result)
> + return result;
>
> /*
> * Linkage
>
>
>
From: Rafael J. Wysocki <[email protected]>
If acpi_add_single_object() runs concurrently with respect to
acpi_scan_clear_dep() which deletes a dependencies list entry where
the device being added is the consumer, the device's dep_unmet
counter may not be updated to reflect that change.
Namely, if the dependencies list entry is deleted right after
calling acpi_scan_dep_init() and before calling acpi_device_add(),
acpi_scan_clear_dep() will not find the device object corresponding
to the consumer device ACPI handle and it will not update its
dep_unmet counter to reflect the deletion of the list entry.
Consequently, the dep_unmet counter of the device will never
become zero going forward which may prevent it from being
completely enumerated.
To address this problem, modify acpi_add_single_object() to run
acpi_tie_acpi_dev(), to attach the ACPI device object created by it
to the corresponding ACPI namespace node, under acpi_dep_list_lock
along with acpi_scan_dep_init() whenever the latter is called.
Signed-off-by: Rafael J. Wysocki <[email protected]>
---
drivers/acpi/scan.c | 46 +++++++++++++++++++++++++++++++++-------------
1 file changed, 33 insertions(+), 13 deletions(-)
Index: linux-pm/drivers/acpi/scan.c
===================================================================
--- linux-pm.orig/drivers/acpi/scan.c
+++ linux-pm/drivers/acpi/scan.c
@@ -657,16 +657,12 @@ static int acpi_tie_acpi_dev(struct acpi
return 0;
}
-int acpi_device_add(struct acpi_device *device,
- void (*release)(struct device *))
+int __acpi_device_add(struct acpi_device *device,
+ void (*release)(struct device *))
{
struct acpi_device_bus_id *acpi_device_bus_id;
int result;
- result = acpi_tie_acpi_dev(device);
- if (result)
- return result;
-
/*
* Linkage
* -------
@@ -755,6 +751,17 @@ err_unlock:
return result;
}
+int acpi_device_add(struct acpi_device *adev, void (*release)(struct device *))
+{
+ int ret;
+
+ ret = acpi_tie_acpi_dev(adev);
+ if (ret)
+ return ret;
+
+ return __acpi_device_add(adev, release);
+}
+
/* --------------------------------------------------------------------------
Device Enumeration
-------------------------------------------------------------------------- */
@@ -1681,14 +1688,10 @@ static void acpi_scan_dep_init(struct ac
{
struct acpi_dep_data *dep;
- mutex_lock(&acpi_dep_list_lock);
-
list_for_each_entry(dep, &acpi_dep_list, node) {
if (dep->consumer == adev->handle)
adev->dep_unmet++;
}
-
- mutex_unlock(&acpi_dep_list_lock);
}
void acpi_device_add_finalize(struct acpi_device *device)
@@ -1707,6 +1710,7 @@ static int acpi_add_single_object(struct
acpi_handle handle, int type, bool dep_init)
{
struct acpi_device *device;
+ bool release_dep_lock = false;
int result;
device = kzalloc(sizeof(struct acpi_device), GFP_KERNEL);
@@ -1720,16 +1724,32 @@ static int acpi_add_single_object(struct
* this must be done before the get power-/wakeup_dev-flags calls.
*/
if (type == ACPI_BUS_TYPE_DEVICE || type == ACPI_BUS_TYPE_PROCESSOR) {
- if (dep_init)
+ if (dep_init) {
+ mutex_lock(&acpi_dep_list_lock);
+ /*
+ * Hold the lock until the acpi_tie_acpi_dev() call
+ * below to prevent concurrent acpi_scan_clear_dep()
+ * from deleting a dependency list entry without
+ * updating dep_unmet for the device.
+ */
+ release_dep_lock = true;
acpi_scan_dep_init(device);
-
+ }
acpi_scan_init_status(device);
}
acpi_bus_get_power_flags(device);
acpi_bus_get_wakeup_device_flags(device);
- result = acpi_device_add(device, acpi_device_release);
+ result = acpi_tie_acpi_dev(device);
+
+ if (release_dep_lock)
+ mutex_unlock(&acpi_dep_list_lock);
+
+ if (result)
+ return result;
+
+ result = __acpi_device_add(device, acpi_device_release);
if (result) {
acpi_device_release(&device->dev);
return result;
From: Rafael J. Wysocki <[email protected]>
If acpi_add_single_object() runs concurrently with respect to
acpi_scan_clear_dep() which deletes a dependencies list entry where
the device being added is the consumer, the device's dep_unmet
counter may not be updated to reflect that change.
Namely, if the dependencies list entry is deleted right after
calling acpi_scan_dep_init() and before calling acpi_device_add(),
acpi_scan_clear_dep() will not find the device object corresponding
to the consumer device ACPI handle and it will not update its
dep_unmet counter to reflect the deletion of the list entry.
Consequently, the dep_unmet counter of the device will never
become zero going forward which may prevent it from being
completely enumerated.
To address this problem, modify acpi_add_single_object() to run
acpi_tie_acpi_dev(), to attach the ACPI device object created by it
to the corresponding ACPI namespace node, under acpi_dep_list_lock
along with acpi_scan_dep_init() whenever the latter is called.
Signed-off-by: Rafael J. Wysocki <[email protected]>
Reviewed-by: Hans de Goede <[email protected]>
---
-> v2:
* Fix memory leak spotted by Hans.
* Add the R-by tag from Hans.
---
drivers/acpi/scan.c | 50 ++++++++++++++++++++++++++++++++------------------
1 file changed, 32 insertions(+), 18 deletions(-)
Index: linux-pm/drivers/acpi/scan.c
===================================================================
--- linux-pm.orig/drivers/acpi/scan.c
+++ linux-pm/drivers/acpi/scan.c
@@ -657,16 +652,12 @@ static int acpi_tie_acpi_dev(struct acpi
return 0;
}
-int acpi_device_add(struct acpi_device *device,
- void (*release)(struct device *))
+int __acpi_device_add(struct acpi_device *device,
+ void (*release)(struct device *))
{
struct acpi_device_bus_id *acpi_device_bus_id;
int result;
- result = acpi_tie_acpi_dev(device);
- if (result)
- return result;
-
/*
* Linkage
* -------
@@ -755,6 +746,17 @@ err_unlock:
return result;
}
+int acpi_device_add(struct acpi_device *adev, void (*release)(struct device *))
+{
+ int ret;
+
+ ret = acpi_tie_acpi_dev(adev);
+ if (ret)
+ return ret;
+
+ return __acpi_device_add(adev, release);
+}
+
/* --------------------------------------------------------------------------
Device Enumeration
-------------------------------------------------------------------------- */
@@ -1681,14 +1683,10 @@ static void acpi_scan_dep_init(struct ac
{
struct acpi_dep_data *dep;
- mutex_lock(&acpi_dep_list_lock);
-
list_for_each_entry(dep, &acpi_dep_list, node) {
if (dep->consumer == adev->handle)
adev->dep_unmet++;
}
-
- mutex_unlock(&acpi_dep_list_lock);
}
void acpi_device_add_finalize(struct acpi_device *device)
@@ -1707,6 +1705,7 @@ static int acpi_add_single_object(struct
acpi_handle handle, int type, bool dep_init)
{
struct acpi_device *device;
+ bool release_dep_lock = false;
int result;
device = kzalloc(sizeof(struct acpi_device), GFP_KERNEL);
@@ -1720,16 +1719,31 @@ static int acpi_add_single_object(struct
* this must be done before the get power-/wakeup_dev-flags calls.
*/
if (type == ACPI_BUS_TYPE_DEVICE || type == ACPI_BUS_TYPE_PROCESSOR) {
- if (dep_init)
+ if (dep_init) {
+ mutex_lock(&acpi_dep_list_lock);
+ /*
+ * Hold the lock until the acpi_tie_acpi_dev() call
+ * below to prevent concurrent acpi_scan_clear_dep()
+ * from deleting a dependency list entry without
+ * updating dep_unmet for the device.
+ */
+ release_dep_lock = true;
acpi_scan_dep_init(device);
-
+ }
acpi_scan_init_status(device);
}
acpi_bus_get_power_flags(device);
acpi_bus_get_wakeup_device_flags(device);
- result = acpi_device_add(device, acpi_device_release);
+ result = acpi_tie_acpi_dev(device);
+
+ if (release_dep_lock)
+ mutex_unlock(&acpi_dep_list_lock);
+
+ if (!result)
+ result = __acpi_device_add(device, acpi_device_release);
+
if (result) {
acpi_device_release(&device->dev);
return result;
Hi "Rafael,
I love your patch! Perhaps something to improve:
[auto build test WARNING on pm/linux-next]
[also build test WARNING on next-20210616]
[cannot apply to linux/master linus/master v5.13-rc6]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/0day-ci/linux/commits/Rafael-J-Wysocki/ACPI-scan-Fixes-and-cleanups-related-to-dependencies-list-handling/20210617-013528
base: https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git linux-next
config: i386-randconfig-s001-20210615 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce:
# apt-get install sparse
# sparse version: v0.6.3-341-g8af24329-dirty
# https://github.com/0day-ci/linux/commit/6369a007980e42b3ba7bbfb9833146f1867c790b
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Rafael-J-Wysocki/ACPI-scan-Fixes-and-cleanups-related-to-dependencies-list-handling/20210617-013528
git checkout 6369a007980e42b3ba7bbfb9833146f1867c790b
# save the attached .config to linux build tree
make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' W=1 ARCH=i386
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email protected]>
sparse warnings: (new ones prefixed by >>)
>> drivers/acpi/scan.c:660:5: sparse: sparse: symbol '__acpi_device_add' was not declared. Should it be static?
Please review and possibly fold the followup patch.
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/[email protected]
drivers/acpi/scan.c:660:5: warning: symbol '__acpi_device_add' was not declared. Should it be static?
Reported-by: kernel test robot <[email protected]>
Signed-off-by: kernel test robot <[email protected]>
---
scan.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index be8b149244220..f30ab5a55a9a4 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -657,8 +657,8 @@ static int acpi_tie_acpi_dev(struct acpi_device *adev)
return 0;
}
-int __acpi_device_add(struct acpi_device *device,
- void (*release)(struct device *))
+static int __acpi_device_add(struct acpi_device *device,
+ void (*release)(struct device *))
{
struct acpi_device_bus_id *acpi_device_bus_id;
int result;
Hi "Rafael,
I love your patch! Perhaps something to improve:
[auto build test WARNING on pm/linux-next]
[also build test WARNING on next-20210616]
[cannot apply to linux/master linus/master v5.13-rc6]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/0day-ci/linux/commits/Rafael-J-Wysocki/ACPI-scan-Fixes-and-cleanups-related-to-dependencies-list-handling/20210617-013528
base: https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git linux-next
config: x86_64-randconfig-b001-20210615 (attached as .config)
compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 64720f57bea6a6bf033feef4a5751ab9c0c3b401)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# install x86_64 cross compiling tool for clang build
# apt-get install binutils-x86-64-linux-gnu
# https://github.com/0day-ci/linux/commit/6369a007980e42b3ba7bbfb9833146f1867c790b
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Rafael-J-Wysocki/ACPI-scan-Fixes-and-cleanups-related-to-dependencies-list-handling/20210617-013528
git checkout 6369a007980e42b3ba7bbfb9833146f1867c790b
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email protected]>
All warnings (new ones prefixed by >>):
>> drivers/acpi/scan.c:660:5: warning: no previous prototype for function '__acpi_device_add' [-Wmissing-prototypes]
int __acpi_device_add(struct acpi_device *device,
^
drivers/acpi/scan.c:660:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
int __acpi_device_add(struct acpi_device *device,
^
static
1 warning generated.
vim +/__acpi_device_add +660 drivers/acpi/scan.c
659
> 660 int __acpi_device_add(struct acpi_device *device,
661 void (*release)(struct device *))
662 {
663 struct acpi_device_bus_id *acpi_device_bus_id;
664 int result;
665
666 /*
667 * Linkage
668 * -------
669 * Link this device to its parent and siblings.
670 */
671 INIT_LIST_HEAD(&device->children);
672 INIT_LIST_HEAD(&device->node);
673 INIT_LIST_HEAD(&device->wakeup_list);
674 INIT_LIST_HEAD(&device->physical_node_list);
675 INIT_LIST_HEAD(&device->del_list);
676 mutex_init(&device->physical_node_lock);
677
678 mutex_lock(&acpi_device_lock);
679
680 acpi_device_bus_id = acpi_device_bus_id_match(acpi_device_hid(device));
681 if (acpi_device_bus_id) {
682 result = acpi_device_set_name(device, acpi_device_bus_id);
683 if (result)
684 goto err_unlock;
685 } else {
686 acpi_device_bus_id = kzalloc(sizeof(*acpi_device_bus_id),
687 GFP_KERNEL);
688 if (!acpi_device_bus_id) {
689 result = -ENOMEM;
690 goto err_unlock;
691 }
692 acpi_device_bus_id->bus_id =
693 kstrdup_const(acpi_device_hid(device), GFP_KERNEL);
694 if (!acpi_device_bus_id->bus_id) {
695 kfree(acpi_device_bus_id);
696 result = -ENOMEM;
697 goto err_unlock;
698 }
699
700 ida_init(&acpi_device_bus_id->instance_ida);
701
702 result = acpi_device_set_name(device, acpi_device_bus_id);
703 if (result) {
704 kfree_const(acpi_device_bus_id->bus_id);
705 kfree(acpi_device_bus_id);
706 goto err_unlock;
707 }
708
709 list_add_tail(&acpi_device_bus_id->node, &acpi_bus_id_list);
710 }
711
712 if (device->parent)
713 list_add_tail(&device->node, &device->parent->children);
714
715 if (device->wakeup.flags.valid)
716 list_add_tail(&device->wakeup_list, &acpi_wakeup_device_list);
717
718 mutex_unlock(&acpi_device_lock);
719
720 if (device->parent)
721 device->dev.parent = &device->parent->dev;
722
723 device->dev.bus = &acpi_bus_type;
724 device->dev.release = release;
725 result = device_add(&device->dev);
726 if (result) {
727 dev_err(&device->dev, "Error registering device\n");
728 goto err;
729 }
730
731 result = acpi_device_setup_files(device);
732 if (result)
733 pr_err("Error creating sysfs interface for device %s\n",
734 dev_name(&device->dev));
735
736 return 0;
737
738 err:
739 mutex_lock(&acpi_device_lock);
740
741 if (device->parent)
742 list_del(&device->node);
743
744 list_del(&device->wakeup_list);
745
746 err_unlock:
747 mutex_unlock(&acpi_device_lock);
748
749 acpi_detach_data(device->handle, acpi_scan_drop_device);
750
751 return result;
752 }
753
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/[email protected]
Hi,
On 6/16/21 8:00 PM, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <[email protected]>
>
> If acpi_add_single_object() runs concurrently with respect to
> acpi_scan_clear_dep() which deletes a dependencies list entry where
> the device being added is the consumer, the device's dep_unmet
> counter may not be updated to reflect that change.
>
> Namely, if the dependencies list entry is deleted right after
> calling acpi_scan_dep_init() and before calling acpi_device_add(),
> acpi_scan_clear_dep() will not find the device object corresponding
> to the consumer device ACPI handle and it will not update its
> dep_unmet counter to reflect the deletion of the list entry.
> Consequently, the dep_unmet counter of the device will never
> become zero going forward which may prevent it from being
> completely enumerated.
>
> To address this problem, modify acpi_add_single_object() to run
> acpi_tie_acpi_dev(), to attach the ACPI device object created by it
> to the corresponding ACPI namespace node, under acpi_dep_list_lock
> along with acpi_scan_dep_init() whenever the latter is called.
>
> Signed-off-by: Rafael J. Wysocki <[email protected]>
> Reviewed-by: Hans de Goede <[email protected]>
FWIW this looks good to me now.
Regards,
Hans
> ---
>
> -> v2:
> * Fix memory leak spotted by Hans.
> * Add the R-by tag from Hans.
>
> ---
> drivers/acpi/scan.c | 50 ++++++++++++++++++++++++++++++++------------------
> 1 file changed, 32 insertions(+), 18 deletions(-)
>
> Index: linux-pm/drivers/acpi/scan.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/scan.c
> +++ linux-pm/drivers/acpi/scan.c
> @@ -657,16 +652,12 @@ static int acpi_tie_acpi_dev(struct acpi
> return 0;
> }
>
> -int acpi_device_add(struct acpi_device *device,
> - void (*release)(struct device *))
> +int __acpi_device_add(struct acpi_device *device,
> + void (*release)(struct device *))
> {
> struct acpi_device_bus_id *acpi_device_bus_id;
> int result;
>
> - result = acpi_tie_acpi_dev(device);
> - if (result)
> - return result;
> -
> /*
> * Linkage
> * -------
> @@ -755,6 +746,17 @@ err_unlock:
> return result;
> }
>
> +int acpi_device_add(struct acpi_device *adev, void (*release)(struct device *))
> +{
> + int ret;
> +
> + ret = acpi_tie_acpi_dev(adev);
> + if (ret)
> + return ret;
> +
> + return __acpi_device_add(adev, release);
> +}
> +
> /* --------------------------------------------------------------------------
> Device Enumeration
> -------------------------------------------------------------------------- */
> @@ -1681,14 +1683,10 @@ static void acpi_scan_dep_init(struct ac
> {
> struct acpi_dep_data *dep;
>
> - mutex_lock(&acpi_dep_list_lock);
> -
> list_for_each_entry(dep, &acpi_dep_list, node) {
> if (dep->consumer == adev->handle)
> adev->dep_unmet++;
> }
> -
> - mutex_unlock(&acpi_dep_list_lock);
> }
>
> void acpi_device_add_finalize(struct acpi_device *device)
> @@ -1707,6 +1705,7 @@ static int acpi_add_single_object(struct
> acpi_handle handle, int type, bool dep_init)
> {
> struct acpi_device *device;
> + bool release_dep_lock = false;
> int result;
>
> device = kzalloc(sizeof(struct acpi_device), GFP_KERNEL);
> @@ -1720,16 +1719,31 @@ static int acpi_add_single_object(struct
> * this must be done before the get power-/wakeup_dev-flags calls.
> */
> if (type == ACPI_BUS_TYPE_DEVICE || type == ACPI_BUS_TYPE_PROCESSOR) {
> - if (dep_init)
> + if (dep_init) {
> + mutex_lock(&acpi_dep_list_lock);
> + /*
> + * Hold the lock until the acpi_tie_acpi_dev() call
> + * below to prevent concurrent acpi_scan_clear_dep()
> + * from deleting a dependency list entry without
> + * updating dep_unmet for the device.
> + */
> + release_dep_lock = true;
> acpi_scan_dep_init(device);
> -
> + }
> acpi_scan_init_status(device);
> }
>
> acpi_bus_get_power_flags(device);
> acpi_bus_get_wakeup_device_flags(device);
>
> - result = acpi_device_add(device, acpi_device_release);
> + result = acpi_tie_acpi_dev(device);
> +
> + if (release_dep_lock)
> + mutex_unlock(&acpi_dep_list_lock);
> +
> + if (!result)
> + result = __acpi_device_add(device, acpi_device_release);
> +
> if (result) {
> acpi_device_release(&device->dev);
> return result;
>
>
>