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From: Jarkko Sakkinen <jarkko@kernel.org>
To: Tyler Hicks <tyhicks@linux.microsoft.com>
Cc: "Jens Wiklander" <jens.wiklander@linaro.org>,
	"Allen Pais" <apais@linux.microsoft.com>,
	"Sumit Garg" <sumit.garg@linaro.org>,
	"Peter Huewe" <peterhuewe@gmx.de>,
	"Jason Gunthorpe" <jgg@ziepe.ca>,
	"Vikas Gupta" <vikas.gupta@broadcom.com>,
	"Thirupathaiah Annapureddy" <thiruan@microsoft.com>,
	"Pavel Tatashin" <pasha.tatashin@soleen.com>,
	"Rafał Miłecki" <zajec5@gmail.com>,
	op-tee@lists.trustedfirmware.org,
	linux-integrity@vger.kernel.org,
	bcm-kernel-feedback-list@broadcom.com,
	linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 7/8] tpm_ftpm_tee: Free and unregister TEE shared memory during kexec
Date: Tue, 15 Jun 2021 16:04:11 +0300	[thread overview]
Message-ID: <20210615130411.hvpnaxnhimjloiz3@kernel.org> (raw)
In-Reply-To: <20210610210913.536081-8-tyhicks@linux.microsoft.com>

On Thu, Jun 10, 2021 at 04:09:12PM -0500, Tyler Hicks wrote:
> 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")
> Signed-off-by: Tyler Hicks <tyhicks@linux.microsoft.com>


Acked-by: Jarkko Sakkinen <jarkko@kernel.org>

> ---
>  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 2ccdf8ac6994..6e3235565a4d 100644
> --- a/drivers/char/tpm/tpm_ftpm_tee.c
> +++ b/drivers/char/tpm/tpm_ftpm_tee.c
> @@ -254,11 +254,11 @@ static int ftpm_tee_probe(struct device *dev)
>  	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;
>  	}
> -- 
> 2.25.1
> 
> 

/Jarkko

  reply	other threads:[~2021-06-15 13:04 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-10 21:09 [PATCH v4 0/8] tee: Improve support for kexec and kdump Tyler Hicks
2021-06-10 21:09 ` [PATCH v4 1/8] optee: Fix memory leak when failing to register shm pages Tyler Hicks
2021-06-11  9:05   ` Jens Wiklander
2021-06-10 21:09 ` [PATCH v4 2/8] optee: Refuse to load the driver under the kdump kernel Tyler Hicks
2021-06-11  9:08   ` Jens Wiklander
2021-06-10 21:09 ` [PATCH v4 3/8] optee: fix tee out of memory failure seen during kexec reboot Tyler Hicks
2021-06-11  9:11   ` Jens Wiklander
2021-06-11 12:53     ` Tyler Hicks
2021-06-14  7:21       ` Jens Wiklander
2021-06-14  7:22   ` Jens Wiklander
2021-06-10 21:09 ` [PATCH v4 4/8] optee: Clear stale cache entries during initialization Tyler Hicks
2021-06-14  8:27   ` Jens Wiklander
2021-06-14 19:06     ` Tyler Hicks
2021-06-14 19:15       ` Jens Wiklander
2021-06-10 21:09 ` [PATCH v4 5/8] tee: add tee_shm_alloc_kernel_buf() Tyler Hicks
2021-06-10 21:09 ` [PATCH v4 6/8] tee: Support kernel shm registration without dma-buf backing Tyler Hicks
2021-06-11  5:16   ` Sumit Garg
2021-06-11 13:09     ` Tyler Hicks
2021-06-11 13:16       ` Tyler Hicks
2021-06-12  8:19         ` Sumit Garg
2021-06-13  8:16           ` Tyler Hicks
2021-06-14  4:59             ` Sumit Garg
2021-06-10 21:09 ` [PATCH v4 7/8] tpm_ftpm_tee: Free and unregister TEE shared memory during kexec Tyler Hicks
2021-06-15 13:04   ` Jarkko Sakkinen [this message]
2021-06-10 21:09 ` [PATCH v4 8/8] firmware: tee_bnxt: Release TEE shm, session, and context " Tyler Hicks

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