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SubjectRe: [PATCH] optee: Suppress false positive kmemleak report in optee_handle_rpc()
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在 12/15/2021 8:29 PM, Jens Wiklander 写道:
> [Please note: This e-mail is from an EXTERNAL e-mail address]
>
> On Mon, Dec 06, 2021 at 08:05:33PM +0800, Xiaolei Wang wrote:
>> We observed the following kmemleak report:
>> unreferenced object 0xffff000007904500 (size 128):
>> comm "swapper/0", pid 1, jiffies 4294892671 (age 44.036s)
>> hex dump (first 32 bytes):
>> 00 47 90 07 00 00 ff ff 60 00 c0 ff 00 00 00 00 .G......`.......
>> 60 00 80 13 00 80 ff ff a0 00 00 00 00 00 00 00 `...............
>> backtrace:
>> [<000000004c12b1c7>] kmem_cache_alloc+0x1ac/0x2f4
>> [<000000005d23eb4f>] tee_shm_alloc+0x78/0x230
>> [<00000000794dd22c>] optee_handle_rpc+0x60/0x6f0
>> [<00000000d9f7c52d>] optee_do_call_with_arg+0x17c/0x1dc
>> [<00000000c35884da>] optee_open_session+0x128/0x1ec
>> [<000000001748f2ff>] tee_client_open_session+0x28/0x40
>> [<00000000aecb5389>] optee_enumerate_devices+0x84/0x2a0
>> [<000000003df18bf1>] optee_probe+0x674/0x6cc
>> [<000000003a4a534a>] platform_drv_probe+0x54/0xb0
>> [<000000000c51ce7d>] really_probe+0xe4/0x4d0
>> [<000000002f04c865>] driver_probe_device+0x58/0xc0
>> [<00000000b485397d>] device_driver_attach+0xc0/0xd0
>> [<00000000c835f0df>] __driver_attach+0x84/0x124
>> [<000000008e5a429c>] bus_for_each_dev+0x70/0xc0
>> [<000000001735e8a8>] driver_attach+0x24/0x30
>> [<000000006d94b04f>] bus_add_driver+0x104/0x1ec
>>
>> This is not a memory leak because we pass the share memory pointer
>> to secure world and would get it from secure world before releasing it.
>>
>> Signed-off-by: Xiaolei Wang <xiaolei.wang@windriver.com>
>> ---
>> drivers/tee/optee/smc_abi.c | 2 ++
>> 1 file changed, 2 insertions(+)
>>
>> diff --git a/drivers/tee/optee/smc_abi.c b/drivers/tee/optee/smc_abi.c
>> index 6196d7c3888f..cf2e3293567d 100644
>> --- a/drivers/tee/optee/smc_abi.c
>> +++ b/drivers/tee/optee/smc_abi.c
>> @@ -23,6 +23,7 @@
>> #include "optee_private.h"
>> #include "optee_smc.h"
>> #include "optee_rpc_cmd.h"
>> +#include <linux/kmemleak.h>
>> #define CREATE_TRACE_POINTS
>> #include "optee_trace.h"
>>
>> @@ -783,6 +784,7 @@ static void optee_handle_rpc(struct tee_context *ctx,
>> param->a4 = 0;
>> param->a5 = 0;
>> }
>> + kmemleak_not_leak(shm);
> Eventually this pointer will be freed below with the call to tee_shm_free().
> I assume than once the memory is freed it's not execused from being a leak
> any longer. Is that correct?

Yes, it is the correct way to release memory through tee_shm_free, but
if a memory leak is detected by the kernel before free memory, it is
obviously a false alarm.

thanks

xiaolei

>
> Thanks,
> Jens
>
>> break;
>> case OPTEE_SMC_RPC_FUNC_FREE:
>> shm = reg_pair_to_ptr(param->a1, param->a2);
>> --
>> 2.25.1
>>

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