From bbdd4a51629ab5f4a09f036f1c142751a9d35645 Mon Sep 17 00:00:00 2001 From: Tyler Hicks Date: Mon, 14 Jun 2021 17:33:16 -0500 Subject: [PATCH] tpm_ftpm_tee: Free and unregister TEE shared memory during kexec commit dfb703ad2a8d366b829818a558337be779746575 upstream. dma-buf backed shared memory cannot be reliably freed and unregistered during a kexec operation even when tee_shm_free() is called on the shm from a .shutdown hook. The problem occurs because dma_buf_put() calls fput() which then uses task_work_add(), with the TWA_RESUME parameter, to queue tee_shm_release() to be called before the current task returns to user mode. However, the current task never returns to user mode before the kexec completes so the memory is never freed nor unregistered. Use tee_shm_alloc_kernel_buf() to avoid dma-buf backed shared memory allocation so that tee_shm_free() can directly call tee_shm_release(). This will ensure that the shm can be freed and unregistered during a kexec operation. Fixes: 09e574831b27 ("tpm/tpm_ftpm_tee: A driver for firmware TPM running inside TEE") Fixes: 1760eb689ed6 ("tpm/tpm_ftpm_tee: add shutdown call back") Cc: stable@vger.kernel.org Signed-off-by: Tyler Hicks Reviewed-by: Sumit Garg Acked-by: Jarkko Sakkinen Signed-off-by: Jens Wiklander Signed-off-by: Greg Kroah-Hartman --- drivers/char/tpm/tpm_ftpm_tee.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/char/tpm/tpm_ftpm_tee.c b/drivers/char/tpm/tpm_ftpm_tee.c index 22bf553ccf9d..69937be2032b 100644 --- a/drivers/char/tpm/tpm_ftpm_tee.c +++ b/drivers/char/tpm/tpm_ftpm_tee.c @@ -255,11 +255,11 @@ static int ftpm_tee_probe(struct platform_device *pdev) pvt_data->session = sess_arg.session; /* Allocate dynamic shared memory with fTPM TA */ - pvt_data->shm = tee_shm_alloc(pvt_data->ctx, - MAX_COMMAND_SIZE + MAX_RESPONSE_SIZE, - TEE_SHM_MAPPED | TEE_SHM_DMA_BUF); + pvt_data->shm = tee_shm_alloc_kernel_buf(pvt_data->ctx, + MAX_COMMAND_SIZE + + MAX_RESPONSE_SIZE); if (IS_ERR(pvt_data->shm)) { - dev_err(dev, "%s: tee_shm_alloc failed\n", __func__); + dev_err(dev, "%s: tee_shm_alloc_kernel_buf failed\n", __func__); rc = -ENOMEM; goto out_shm_alloc; }