diff mbox series

ACPICA: fix a memleak issue related to ACPI/GPIO

Message ID 1620790207-128605-1-git-send-email-chenxiang66@hisilicon.com
State New
Headers show
Series ACPICA: fix a memleak issue related to ACPI/GPIO | expand

Commit Message

chenxiang May 12, 2021, 3:30 a.m. UTC
From: Xiang Chen <chenxiang66@hisilicon.com>

There is a memleak reported as follows:

unreferenced object 0xffff00208ff85a00 (size 128):
  comm "swapper/0", pid 1, jiffies 4294892588 (age 887.572s)
  hex dump (first 32 bytes):
    00 00 00 00 02 00 00 00 08 5a f8 8f 20 00 ff ff  .........Z.. ...
    08 5a f8 8f 20 00 ff ff 00 00 00 00 00 00 00 00  .Z.. ...........
backtrace:
    [<00000000bc25bad8>] slab_post_alloc_hook+0x80/0x2e0
    [<000000008d547074>] kmem_cache_alloc+0x194/0x2c0
    [<00000000b08da9ad>] acpi_os_create_semaphore+0x3c/0x78
    [<0000000024816c0a>] acpi_ev_install_space_handler+0x214/0x274
    [<00000000d93a5ac2>] acpi_install_address_space_handler+0x64/0xb0
    [<0000000098c37a45>] acpi_gpiochip_add+0x130/0x348
    [<00000000c1cf4b42>] gpiochip_add_data_with_key+0x79c/0xdd0
    [<000000005ce539e9>] devm_gpiochip_add_data_with_key+0x30/0x90
    [<00000000a3038b8d>] dwapb_gpio_probe+0x3e4/0x7e8
    [<0000000047a03eba>] platform_probe+0x68/0xe0
    [<00000000dc15c501>] really_probe+0x17c/0x4a0
    [<00000000aa1f123d>] driver_probe_device+0x68/0xd0
    [<00000000d97646e0>] device_driver_attach+0x74/0x80
    [<0000000073d5b3e5>] __driver_attach+0x8c/0xe0
    [<00000000ff60d118>] bus_for_each_dev+0x7c/0xd8
    [<00000000b018393d>] driver_attach+0x24/0x30

It requires to delete the handler object in function 
acpi_remove_address_space_handler() but it just up the sem with function
acpi_os_release_mutex(), so use acpi_os_delete_mutex() instead of 
acpi_os_release_mutex() in function acpi_remove_address_space_handler().

Signed-off-by: Xiang Chen <chenxiang66@hisilicon.com>
---
 drivers/acpi/acpica/evxfregn.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Kaneda, Erik May 17, 2021, 6:54 p.m. UTC | #1
> -----Original Message-----
> From: chenxiang <chenxiang66@hisilicon.com>
> Sent: Tuesday, May 11, 2021 8:30 PM
> To: Moore, Robert <robert.moore@intel.com>; Kaneda, Erik
> <erik.kaneda@intel.com>; Wysocki, Rafael J <rafael.j.wysocki@intel.com>;
> hoan@os.amperecomputing.com; fancer.lancer@gmail.com
> Cc: linux-acpi@vger.kernel.org; linux-gpio@vger.kernel.org;
> linuxarm@huawei.com; Xiang Chen <chenxiang66@hisilicon.com>
> Subject: [PATCH] ACPICA: fix a memleak issue related to ACPI/GPIO
> 
> From: Xiang Chen <chenxiang66@hisilicon.com>
> 
> There is a memleak reported as follows:
> 
> unreferenced object 0xffff00208ff85a00 (size 128):
>   comm "swapper/0", pid 1, jiffies 4294892588 (age 887.572s)
>   hex dump (first 32 bytes):
>     00 00 00 00 02 00 00 00 08 5a f8 8f 20 00 ff ff  .........Z.. ...
>     08 5a f8 8f 20 00 ff ff 00 00 00 00 00 00 00 00  .Z.. ...........
> backtrace:
>     [<00000000bc25bad8>] slab_post_alloc_hook+0x80/0x2e0
>     [<000000008d547074>] kmem_cache_alloc+0x194/0x2c0
>     [<00000000b08da9ad>] acpi_os_create_semaphore+0x3c/0x78
>     [<0000000024816c0a>] acpi_ev_install_space_handler+0x214/0x274
>     [<00000000d93a5ac2>] acpi_install_address_space_handler+0x64/0xb0
>     [<0000000098c37a45>] acpi_gpiochip_add+0x130/0x348
>     [<00000000c1cf4b42>] gpiochip_add_data_with_key+0x79c/0xdd0
>     [<000000005ce539e9>] devm_gpiochip_add_data_with_key+0x30/0x90
>     [<00000000a3038b8d>] dwapb_gpio_probe+0x3e4/0x7e8
>     [<0000000047a03eba>] platform_probe+0x68/0xe0
>     [<00000000dc15c501>] really_probe+0x17c/0x4a0
>     [<00000000aa1f123d>] driver_probe_device+0x68/0xd0
>     [<00000000d97646e0>] device_driver_attach+0x74/0x80
>     [<0000000073d5b3e5>] __driver_attach+0x8c/0xe0
>     [<00000000ff60d118>] bus_for_each_dev+0x7c/0xd8
>     [<00000000b018393d>] driver_attach+0x24/0x30
> 
> It requires to delete the handler object in function
> acpi_remove_address_space_handler() but it just up the sem with function
> acpi_os_release_mutex(), so use acpi_os_delete_mutex() instead of
> acpi_os_release_mutex() in function
> acpi_remove_address_space_handler().
> 
> Signed-off-by: Xiang Chen <chenxiang66@hisilicon.com>
> ---
>  drivers/acpi/acpica/evxfregn.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/acpi/acpica/evxfregn.c b/drivers/acpi/acpica/evxfregn.c
> index b1ff0a8..4db0bec 100644
> --- a/drivers/acpi/acpica/evxfregn.c
> +++ b/drivers/acpi/acpica/evxfregn.c
> @@ -201,7 +201,7 @@ acpi_remove_address_space_handler(acpi_handle
> device,
> 
>  			/* Now we can delete the handler object */
> 

Hi Xiang,
 
> -			acpi_os_release_mutex(handler_obj-
> >address_space.
> +			acpi_os_delete_mutex(handler_obj->address_space.
>  					      context_mutex);

Thanks for this suggestion! Instead of acpi_os_delete_mutex, could you try using acpi_ut_remove_reference instead?
I believe this will is a safer option. Please test this and see if it fixes the memory leak.

Thanks,
Erik

>  			acpi_ut_remove_reference(handler_obj);
>  			goto unlock_and_exit;
> --
> 2.8.1
chenxiang May 18, 2021, 2:02 a.m. UTC | #2
Hi Erik,


在 2021/5/18 2:54, Kaneda, Erik 写道:
>
>> -----Original Message-----
>> From: chenxiang <chenxiang66@hisilicon.com>
>> Sent: Tuesday, May 11, 2021 8:30 PM
>> To: Moore, Robert <robert.moore@intel.com>; Kaneda, Erik
>> <erik.kaneda@intel.com>; Wysocki, Rafael J <rafael.j.wysocki@intel.com>;
>> hoan@os.amperecomputing.com; fancer.lancer@gmail.com
>> Cc: linux-acpi@vger.kernel.org; linux-gpio@vger.kernel.org;
>> linuxarm@huawei.com; Xiang Chen <chenxiang66@hisilicon.com>
>> Subject: [PATCH] ACPICA: fix a memleak issue related to ACPI/GPIO
>>
>> From: Xiang Chen <chenxiang66@hisilicon.com>
>>
>> There is a memleak reported as follows:
>>
>> unreferenced object 0xffff00208ff85a00 (size 128):
>>    comm "swapper/0", pid 1, jiffies 4294892588 (age 887.572s)
>>    hex dump (first 32 bytes):
>>      00 00 00 00 02 00 00 00 08 5a f8 8f 20 00 ff ff  .........Z.. ...
>>      08 5a f8 8f 20 00 ff ff 00 00 00 00 00 00 00 00  .Z.. ...........
>> backtrace:
>>      [<00000000bc25bad8>] slab_post_alloc_hook+0x80/0x2e0
>>      [<000000008d547074>] kmem_cache_alloc+0x194/0x2c0
>>      [<00000000b08da9ad>] acpi_os_create_semaphore+0x3c/0x78
>>      [<0000000024816c0a>] acpi_ev_install_space_handler+0x214/0x274
>>      [<00000000d93a5ac2>] acpi_install_address_space_handler+0x64/0xb0
>>      [<0000000098c37a45>] acpi_gpiochip_add+0x130/0x348
>>      [<00000000c1cf4b42>] gpiochip_add_data_with_key+0x79c/0xdd0
>>      [<000000005ce539e9>] devm_gpiochip_add_data_with_key+0x30/0x90
>>      [<00000000a3038b8d>] dwapb_gpio_probe+0x3e4/0x7e8
>>      [<0000000047a03eba>] platform_probe+0x68/0xe0
>>      [<00000000dc15c501>] really_probe+0x17c/0x4a0
>>      [<00000000aa1f123d>] driver_probe_device+0x68/0xd0
>>      [<00000000d97646e0>] device_driver_attach+0x74/0x80
>>      [<0000000073d5b3e5>] __driver_attach+0x8c/0xe0
>>      [<00000000ff60d118>] bus_for_each_dev+0x7c/0xd8
>>      [<00000000b018393d>] driver_attach+0x24/0x30
>>
>> It requires to delete the handler object in function
>> acpi_remove_address_space_handler() but it just up the sem with function
>> acpi_os_release_mutex(), so use acpi_os_delete_mutex() instead of
>> acpi_os_release_mutex() in function
>> acpi_remove_address_space_handler().
>>
>> Signed-off-by: Xiang Chen <chenxiang66@hisilicon.com>
>> ---
>>   drivers/acpi/acpica/evxfregn.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/acpi/acpica/evxfregn.c b/drivers/acpi/acpica/evxfregn.c
>> index b1ff0a8..4db0bec 100644
>> --- a/drivers/acpi/acpica/evxfregn.c
>> +++ b/drivers/acpi/acpica/evxfregn.c
>> @@ -201,7 +201,7 @@ acpi_remove_address_space_handler(acpi_handle
>> device,
>>
>>   			/* Now we can delete the handler object */
>>
> Hi Xiang,
>   
>> -			acpi_os_release_mutex(handler_obj-
>>> address_space.
>> +			acpi_os_delete_mutex(handler_obj->address_space.
>>   					      context_mutex);
> Thanks for this suggestion! Instead of acpi_os_delete_mutex, could you try using acpi_ut_remove_reference instead?
> I believe this will is a safer option. Please test this and see if it fixes the memory leak.

But there is already acpi_ut_remove_reference(handler_obj) behind it.

>
> Thanks,
> Erik
>
>>   			acpi_ut_remove_reference(handler_obj);
>>   			goto unlock_and_exit;
>> --
>> 2.8.1
>
> .
>
Kaneda, Erik May 18, 2021, 9:35 p.m. UTC | #3
> -----Original Message-----
> From: chenxiang (M) <chenxiang66@hisilicon.com>
> Sent: Monday, May 17, 2021 7:02 PM
> To: Kaneda, Erik <erik.kaneda@intel.com>; Moore, Robert
> <robert.moore@intel.com>; Wysocki, Rafael J <rafael.j.wysocki@intel.com>;
> hoan@os.amperecomputing.com; fancer.lancer@gmail.com
> Cc: linux-acpi@vger.kernel.org; linux-gpio@vger.kernel.org;
> linuxarm@huawei.com
> Subject: Re: [PATCH] ACPICA: fix a memleak issue related to ACPI/GPIO
> 
> Hi Erik,
> 
> 
> 在 2021/5/18 2:54, Kaneda, Erik 写道:
> >
> >> -----Original Message-----
> >> From: chenxiang <chenxiang66@hisilicon.com>
> >> Sent: Tuesday, May 11, 2021 8:30 PM
> >> To: Moore, Robert <robert.moore@intel.com>; Kaneda, Erik
> >> <erik.kaneda@intel.com>; Wysocki, Rafael J
> <rafael.j.wysocki@intel.com>;
> >> hoan@os.amperecomputing.com; fancer.lancer@gmail.com
> >> Cc: linux-acpi@vger.kernel.org; linux-gpio@vger.kernel.org;
> >> linuxarm@huawei.com; Xiang Chen <chenxiang66@hisilicon.com>
> >> Subject: [PATCH] ACPICA: fix a memleak issue related to ACPI/GPIO
> >>
> >> From: Xiang Chen <chenxiang66@hisilicon.com>
> >>
> >> There is a memleak reported as follows:
> >>
> >> unreferenced object 0xffff00208ff85a00 (size 128):
> >>    comm "swapper/0", pid 1, jiffies 4294892588 (age 887.572s)
> >>    hex dump (first 32 bytes):
> >>      00 00 00 00 02 00 00 00 08 5a f8 8f 20 00 ff ff  .........Z.. ...
> >>      08 5a f8 8f 20 00 ff ff 00 00 00 00 00 00 00 00  .Z.. ...........
> >> backtrace:
> >>      [<00000000bc25bad8>] slab_post_alloc_hook+0x80/0x2e0
> >>      [<000000008d547074>] kmem_cache_alloc+0x194/0x2c0
> >>      [<00000000b08da9ad>] acpi_os_create_semaphore+0x3c/0x78
> >>      [<0000000024816c0a>] acpi_ev_install_space_handler+0x214/0x274
> >>      [<00000000d93a5ac2>] acpi_install_address_space_handler+0x64/0xb0
> >>      [<0000000098c37a45>] acpi_gpiochip_add+0x130/0x348
> >>      [<00000000c1cf4b42>] gpiochip_add_data_with_key+0x79c/0xdd0
> >>      [<000000005ce539e9>]
> devm_gpiochip_add_data_with_key+0x30/0x90
> >>      [<00000000a3038b8d>] dwapb_gpio_probe+0x3e4/0x7e8
> >>      [<0000000047a03eba>] platform_probe+0x68/0xe0
> >>      [<00000000dc15c501>] really_probe+0x17c/0x4a0
> >>      [<00000000aa1f123d>] driver_probe_device+0x68/0xd0
> >>      [<00000000d97646e0>] device_driver_attach+0x74/0x80
> >>      [<0000000073d5b3e5>] __driver_attach+0x8c/0xe0
> >>      [<00000000ff60d118>] bus_for_each_dev+0x7c/0xd8
> >>      [<00000000b018393d>] driver_attach+0x24/0x30
> >>
> >> It requires to delete the handler object in function
> >> acpi_remove_address_space_handler() but it just up the sem with
> function
> >> acpi_os_release_mutex(), so use acpi_os_delete_mutex() instead of
> >> acpi_os_release_mutex() in function
> >> acpi_remove_address_space_handler().
> >>
> >> Signed-off-by: Xiang Chen <chenxiang66@hisilicon.com>
> >> ---
> >>   drivers/acpi/acpica/evxfregn.c | 2 +-
> >>   1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/acpi/acpica/evxfregn.c
> b/drivers/acpi/acpica/evxfregn.c
> >> index b1ff0a8..4db0bec 100644
> >> --- a/drivers/acpi/acpica/evxfregn.c
> >> +++ b/drivers/acpi/acpica/evxfregn.c
> >> @@ -201,7 +201,7 @@
> acpi_remove_address_space_handler(acpi_handle
> >> device,
> >>
> >>   			/* Now we can delete the handler object */
> >>
> > Hi Xiang,
> >
> >> -			acpi_os_release_mutex(handler_obj-
> >>> address_space.
> >> +			acpi_os_delete_mutex(handler_obj->address_space.
> >>   					      context_mutex);
> > Thanks for this suggestion! Instead of acpi_os_delete_mutex, could you try
> using acpi_ut_remove_reference instead?
> > I believe this will is a safer option. Please test this and see if it fixes the
> memory leak.
> 
Hi,

> But there is already acpi_ut_remove_reference(handler_obj) behind it.

The delete mutex could result in unexpected behavior because it's not always the case that acpi_ut_remove_reference will clean up the object. This function cleans up the object if the reference count is 0 so we should add the delete mutex during the deletion instead.

Could you try this code to see if it fixes the leak?

diff --git a/drivers/acpi/acpica/utdelete.c b/drivers/acpi/acpica/utdelete.c
index 624a26794d55..e5ba9795ec69 100644
--- a/drivers/acpi/acpica/utdelete.c
+++ b/drivers/acpi/acpica/utdelete.c
@@ -285,6 +285,14 @@ static void acpi_ut_delete_internal_obj(union acpi_operand_object *object)
                }
                break;

+       case ACPI_TYPE_LOCAL_ADDRESS_HANDLER:
+
+               ACPI_DEBUG_PRINT((ACPI_DB_ALLOCATIONS,
+                                 "***** Address handler %p\n", object));
+
+               acpi_os_delete_mutex(object->address_space.context_mutex);
+               break;
+
        default:

                break;

> 
> >
> > Thanks,
> > Erik
> >
> >>   			acpi_ut_remove_reference(handler_obj);
> >>   			goto unlock_and_exit;
> >> --
> >> 2.8.1
> >
> > .
> >
>
chenxiang May 19, 2021, 10:51 a.m. UTC | #4
Hi Erik,


在 2021/5/19 5:35, Kaneda, Erik 写道:
>
>> -----Original Message-----
>> From: chenxiang (M) <chenxiang66@hisilicon.com>
>> Sent: Monday, May 17, 2021 7:02 PM
>> To: Kaneda, Erik <erik.kaneda@intel.com>; Moore, Robert
>> <robert.moore@intel.com>; Wysocki, Rafael J <rafael.j.wysocki@intel.com>;
>> hoan@os.amperecomputing.com; fancer.lancer@gmail.com
>> Cc: linux-acpi@vger.kernel.org; linux-gpio@vger.kernel.org;
>> linuxarm@huawei.com
>> Subject: Re: [PATCH] ACPICA: fix a memleak issue related to ACPI/GPIO
>>
>> Hi Erik,
>>
>>
>> 在 2021/5/18 2:54, Kaneda, Erik 写道:
>>>> -----Original Message-----
>>>> From: chenxiang <chenxiang66@hisilicon.com>
>>>> Sent: Tuesday, May 11, 2021 8:30 PM
>>>> To: Moore, Robert <robert.moore@intel.com>; Kaneda, Erik
>>>> <erik.kaneda@intel.com>; Wysocki, Rafael J
>> <rafael.j.wysocki@intel.com>;
>>>> hoan@os.amperecomputing.com; fancer.lancer@gmail.com
>>>> Cc: linux-acpi@vger.kernel.org; linux-gpio@vger.kernel.org;
>>>> linuxarm@huawei.com; Xiang Chen <chenxiang66@hisilicon.com>
>>>> Subject: [PATCH] ACPICA: fix a memleak issue related to ACPI/GPIO
>>>>
>>>> From: Xiang Chen <chenxiang66@hisilicon.com>
>>>>
>>>> There is a memleak reported as follows:
>>>>
>>>> unreferenced object 0xffff00208ff85a00 (size 128):
>>>>     comm "swapper/0", pid 1, jiffies 4294892588 (age 887.572s)
>>>>     hex dump (first 32 bytes):
>>>>       00 00 00 00 02 00 00 00 08 5a f8 8f 20 00 ff ff  .........Z.. ...
>>>>       08 5a f8 8f 20 00 ff ff 00 00 00 00 00 00 00 00  .Z.. ...........
>>>> backtrace:
>>>>       [<00000000bc25bad8>] slab_post_alloc_hook+0x80/0x2e0
>>>>       [<000000008d547074>] kmem_cache_alloc+0x194/0x2c0
>>>>       [<00000000b08da9ad>] acpi_os_create_semaphore+0x3c/0x78
>>>>       [<0000000024816c0a>] acpi_ev_install_space_handler+0x214/0x274
>>>>       [<00000000d93a5ac2>] acpi_install_address_space_handler+0x64/0xb0
>>>>       [<0000000098c37a45>] acpi_gpiochip_add+0x130/0x348
>>>>       [<00000000c1cf4b42>] gpiochip_add_data_with_key+0x79c/0xdd0
>>>>       [<000000005ce539e9>]
>> devm_gpiochip_add_data_with_key+0x30/0x90
>>>>       [<00000000a3038b8d>] dwapb_gpio_probe+0x3e4/0x7e8
>>>>       [<0000000047a03eba>] platform_probe+0x68/0xe0
>>>>       [<00000000dc15c501>] really_probe+0x17c/0x4a0
>>>>       [<00000000aa1f123d>] driver_probe_device+0x68/0xd0
>>>>       [<00000000d97646e0>] device_driver_attach+0x74/0x80
>>>>       [<0000000073d5b3e5>] __driver_attach+0x8c/0xe0
>>>>       [<00000000ff60d118>] bus_for_each_dev+0x7c/0xd8
>>>>       [<00000000b018393d>] driver_attach+0x24/0x30
>>>>
>>>> It requires to delete the handler object in function
>>>> acpi_remove_address_space_handler() but it just up the sem with
>> function
>>>> acpi_os_release_mutex(), so use acpi_os_delete_mutex() instead of
>>>> acpi_os_release_mutex() in function
>>>> acpi_remove_address_space_handler().
>>>>
>>>> Signed-off-by: Xiang Chen <chenxiang66@hisilicon.com>
>>>> ---
>>>>    drivers/acpi/acpica/evxfregn.c | 2 +-
>>>>    1 file changed, 1 insertion(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/acpi/acpica/evxfregn.c
>> b/drivers/acpi/acpica/evxfregn.c
>>>> index b1ff0a8..4db0bec 100644
>>>> --- a/drivers/acpi/acpica/evxfregn.c
>>>> +++ b/drivers/acpi/acpica/evxfregn.c
>>>> @@ -201,7 +201,7 @@
>> acpi_remove_address_space_handler(acpi_handle
>>>> device,
>>>>
>>>>    			/* Now we can delete the handler object */
>>>>
>>> Hi Xiang,
>>>
>>>> -			acpi_os_release_mutex(handler_obj-
>>>>> address_space.
>>>> +			acpi_os_delete_mutex(handler_obj->address_space.
>>>>    					      context_mutex);
>>> Thanks for this suggestion! Instead of acpi_os_delete_mutex, could you try
>> using acpi_ut_remove_reference instead?
>>> I believe this will is a safer option. Please test this and see if it fixes the
>> memory leak.
>>
> Hi,
>
>> But there is already acpi_ut_remove_reference(handler_obj) behind it.
> The delete mutex could result in unexpected behavior because it's not always the case that acpi_ut_remove_reference will clean up the object. This function cleans up the object if the reference count is 0 so we should add the delete mutex during the deletion instead.
>
> Could you try this code to see if it fixes the leak?

I have tested the change, and it fixes the leak, and so please feel free 
to add:
Tested-by: Xiang Chen <chenxiang66@hisilicon.com>

>
> diff --git a/drivers/acpi/acpica/utdelete.c b/drivers/acpi/acpica/utdelete.c
> index 624a26794d55..e5ba9795ec69 100644
> --- a/drivers/acpi/acpica/utdelete.c
> +++ b/drivers/acpi/acpica/utdelete.c
> @@ -285,6 +285,14 @@ static void acpi_ut_delete_internal_obj(union acpi_operand_object *object)
>                  }
>                  break;
>
> +       case ACPI_TYPE_LOCAL_ADDRESS_HANDLER:
> +
> +               ACPI_DEBUG_PRINT((ACPI_DB_ALLOCATIONS,
> +                                 "***** Address handler %p\n", object));
> +
> +               acpi_os_delete_mutex(object->address_space.context_mutex);
> +               break;
> +
>          default:
>
>                  break;
>
>>> Thanks,
>>> Erik
>>>
>>>>    			acpi_ut_remove_reference(handler_obj);
>>>>    			goto unlock_and_exit;
>>>> --
>>>> 2.8.1
>>> .
>>>
diff mbox series

Patch

diff --git a/drivers/acpi/acpica/evxfregn.c b/drivers/acpi/acpica/evxfregn.c
index b1ff0a8..4db0bec 100644
--- a/drivers/acpi/acpica/evxfregn.c
+++ b/drivers/acpi/acpica/evxfregn.c
@@ -201,7 +201,7 @@  acpi_remove_address_space_handler(acpi_handle device,
 
 			/* Now we can delete the handler object */
 
-			acpi_os_release_mutex(handler_obj->address_space.
+			acpi_os_delete_mutex(handler_obj->address_space.
 					      context_mutex);
 			acpi_ut_remove_reference(handler_obj);
 			goto unlock_and_exit;