Re: [PATCH] ACPICA: fix a memleak issue related to ACPI/GPIO

["chenxiang (M)" <chenxiang66@hisilicon.com>]

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
>
> .
>