Re: [PATCH] optee: Suppress false positive kmemleak report in optee_handle_rpc()

-----Original Message----- From: Sumit Gargsumit.garg@linaro.org Sent: Thursday, December 9, 2021 7:41 PM To: Wang, XiaoleiXiaolei.Wang@windriver.com Cc:jens.wiklander@linaro.org;op-tee@lists.trustedfirmware.org;linux-kernel@vger.kernel.org Subject: Re: [PATCH] optee: Suppress false positive kmemleak report in optee_handle_rpc()

[Please note: This e-mail is from an EXTERNAL e-mail address]

On Mon, 6 Dec 2021 at 17:35, Xiaolei Wangxiaolei.wang@windriver.com 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.

IMO, we need to cross-check optee-os if it's responsible for leaking kernel memory.

Hi Sumit

You mean we need to check whether there is a real memory leak,

if being secure world just allocates kernel memory via OPTEE_SMC_RPC_FUNC_ALLOC

and until the end, there is no free it via OPTEE_SMC_RPC_FUNC_FREE,

then we should judge it as a memory leak.

thanks

xiaolei

-Sumit

...

Signed-off-by: Xiaolei Wangxiaolei.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);
             break;
     case OPTEE_SMC_RPC_FUNC_FREE:
             shm = reg_pair_to_ptr(param->a1, param->a2);
  

-- 2.25.1