On Fri, Mar 27, 2026 at 09:01:15AM +0000, Shf Chen (陳少甫) via OP-TEE wrote:
Hi,
We found a possible race condition issue during OP-TEE kernel driver probing the device. A NULL pointer dereference exception can happen when another kernel driver open OP-TEE context with tee_client_open_context() then do a SMC call to OP-TEE. Below is the exception:
How is your kernel driver being probed? Have you registered it as a proper TEE bus driver? Any custom ways to invoke TEE kernel client APIs are surely susceptible to races like the one you mentioned below.
-Sumit
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 Mem abort info: ESR = 0x0000000096000005 EC = 0x25: DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 FSC = 0x05: level 1 translation fault Data abort info: ISV = 0, ISS = 0x00000005, ISS2 = 0x00000000 CM = 0, WnR = 0, TnD = 0, TagAccess = 0 GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 user pgtable: 4k pages, 39-bit VAs, pgdp=00000001026bb000 [0000000000000000] pgd=0000000000000000, p4d=0000000000000000, pud=0000000000000000 Internal error: Oops: 0000000096000005 [#1] PREEMPT SMP Workqueue: events_unbound deferred_probe_work_func pstate: 03400005 (nzcv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--) pc : optee_cq_wait_init+0x78/0x124 [optee] lr : optee_cq_wait_init+0x60/0x124 [optee] sp : ffffffc081fcb7f0 x29: ffffffc081fcb7f0 x28: 0000000000000000 x27: 0000000000001000 x26: ffffff8080e42c60 x25: ffffff8084d46040 x24: 0000000000000000 x23: 0000000000000000 x22: ffffffc081fcb8c0 x21: ffffffc081fcb8a8 x20: 0000000000000000 x19: ffffff8082741570 x18: ffffffe572f8ca00 x17: 00000000fa28650f x16: 00000000fa28650f x15: ffffff8084d47000 x14: 0000000000000000 x13: 0000000000000000 x12: 0000000084d47000 x11: 0000000000000000 x10: 0000000032000012 x9 : 04d4600000000001 x8 : ffffffc081fcb8c8 x7 : 0000000000000000 x6 : 000000000000003f x5 : ffffff83c86649e0 x4 : 0000000000000008 x3 : 0000000000000000 x2 : ffffff80827415a0 x1 : 0000000000000000 x0 : ffffffc081fcb8c0 Call trace: optee_cq_wait_init+0x78/0x124 [optee f6dbc35f8d96acbe1f3c329d72018151d796208d] optee_smc_do_call_with_arg+0x12c/0x95c [optee f6dbc35f8d96acbe1f3c329d72018151d796208d] optee_shm_register+0x284/0x360 [optee f6dbc35f8d96acbe1f3c329d72018151d796208d] register_shm_helper+0x1a4/0x2f4 [tee cdd8a0d077d984bda1f31f9e8903836edbe46603] tee_shm_register_kernel_buf+0x60/0x90 [tee cdd8a0d077d984bda1f31f9e8903836edbe46603] cmdq_sec_allocate_wsm+0x58/0xc4 [mtk_cmdq_sec_mbox ac82dc958e32252a21c6ce55bb8839ebb288387a] cmdq_sec_probe+0x80/0x4a0 [mtk_cmdq_sec_mbox ac82dc958e32252a21c6ce55bb8839ebb288387a]
We found the optee->call_queue hasn't been initialized when our driver called OP-TEE, and it might have some issues about the device data structure initialize order in optee_probe()[drivers/tee/optee/smc_abi.c]:
rc = tee_device_register(optee->teedev); // <----- TEE device register here if (rc) goto err_unreg_supp_teedev;
rc = tee_device_register(optee->supp_teedev); if (rc) goto err_unreg_supp_teedev;
optee_cq_init(&optee->call_queue, thread_count); // <----- Some data structures are initialized afterwards optee_supp_init(&optee->supp); optee->smc.memremaped_shm = memremaped_shm; optee->pool = pool; optee_shm_arg_cache_init(optee, arg_cache_flags); mutex_init(&optee->rpmb_dev_mutex);
We want to ask if the data structure initialization should be done before the tee device registration?
Best regards, Shao-Fu Chen