Messages in this thread | | | From | Sumit Garg <> | Date | Mon, 13 Dec 2021 14:34:13 +0530 | Subject | Re: [PATCH] optee: Suppress false positive kmemleak report in optee_handle_rpc() |
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On Mon, 13 Dec 2021 at 14:25, wangxiaolei <xiaolei.wang@windriver.com> wrote: > > > On 12/10/21 5:38 PM, Sumit Garg wrote: > > [Please note: This e-mail is from an EXTERNAL e-mail address] > > > > On Fri, 10 Dec 2021 at 13:40, Jerome Forissier <jerome@forissier.org> wrote: > >> +CC Jens, Etienne > >> > >> On 12/10/21 06:00, Sumit Garg wrote: > >>> On Fri, 10 Dec 2021 at 09:42, Wang, Xiaolei <Xiaolei.Wang@windriver.com> wrote: > >>>> -----Original Message----- > >>>> From: Sumit Garg <sumit.garg@linaro.org> > >>>> Sent: Thursday, December 9, 2021 7:41 PM > >>>> To: Wang, Xiaolei <Xiaolei.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 Wang <xiaolei.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. > >>>>> How about if it's actually a memory leak caused by the secure world? > >>>>> An example being secure world just allocates kernel memory via OPTEE_SMC_RPC_FUNC_ALLOC and doesn't free it via OPTEE_SMC_RPC_FUNC_FREE. > >>>>> 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 memleak, > >>>> If being secure world just allocate kernel memory via OPTEE_SMC_PRC_FUNC_ALLOC and until the end, there is no free > >>>> It via OPTEE_SMC_PRC_FUNC_FREE, then we should judge it as a memory leak, wo need to judge whether it is caused by secure os? > >>> Yes. AFAICT, optee-os should allocate shared memory to communicate > >>> with tee-supplicant. So once the communication is done, the underlying > >>> shared memory should be freed. I can't think of any scenario where > >>> optee-os should keep hold-off shared memory indefinitely. > >> I believe it can happen when OP-TEE's CFG_PREALLOC_RPC_CACHE is y. See > >> the config file [1] and the commit which introduced this config [2]. > > Okay, I see the reasoning. So during the OP-TEE driver's lifetime, the > > RPC shared memory remains allocated. I guess that is done primarily > > for performance reasons. > > > > But still it doesn't feel appropriate that we term all RPC shm > > allocations as not leaking memory as we might miss obvious ones. > > > > Xiaolei, > > > > Can you once test with CFG_PREALLOC_RPC_CACHE=n while compiling > > optee-os and see if the observed memory leak disappears or not? > > > > -Sumit > > Hi sumit > > > The version I am using has not increased the CFG_PREALLOC_RPC_CACHE > > switch, I checked out to the latest version, but because of the need for > > additional patches for the imx8 platform, I still have no way to test the > > CFG_PREALLOC_RPC_CACHE=n situation >
Can you just try to backport this [1] patch to your imx8 optee-os tree and test?
[1] https://github.com/OP-TEE/optee_os/commit/8887663248ad
-Sumit
> > thanks > > xiaolei > > > > >> [1] https://github.com/OP-TEE/optee_os/blob/3.15.0/mk/config.mk#L709 > >> [2] https://github.com/OP-TEE/optee_os/commit/8887663248ad > >> > >> -- > >> Jerome
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