On Thu, 13 Sep 2018 at 09:59, Christoph Manszewski
<c.manszewski@xxxxxxxxxxx> wrote:
>
> Remove a race condition introduced by error path in functions:
> s5p_aes_interrupt and s5p_aes_crypt_start. Setting the busy field of
> struct s5p_aes_dev to false made it possible for s5p_tasklet_cb to
> change the req field, before s5p_aes_complete was called.
Nice catch. Indeed the code looks racy.
>
> Change the first parameter of s5p_aes_complete to struct
> ablkcipher_request. Before spin_unlock, make a copy of the currently
> handled request, to ensure s5p_aes_complete function call with the
> correct request.
>
> Signed-off-by: Christoph Manszewski <c.manszewski@xxxxxxxxxxx>
> ---
> drivers/crypto/s5p-sss.c | 13 ++++++++-----
> 1 file changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/crypto/s5p-sss.c b/drivers/crypto/s5p-sss.c
> index faa282074e5a..0cf3f12d8f74 100644
> --- a/drivers/crypto/s5p-sss.c
> +++ b/drivers/crypto/s5p-sss.c
> @@ -475,9 +475,9 @@ static void s5p_sg_done(struct s5p_aes_dev *dev)
> }
>
> /* Calls the completion. Cannot be called with dev->lock hold. */
> -static void s5p_aes_complete(struct s5p_aes_dev *dev, int err)
> +static void s5p_aes_complete(struct ablkcipher_request *req, int err)
> {
> - dev->req->base.complete(&dev->req->base, err);
> + req->base.complete(&req->base, err);
> }
>
> static void s5p_unset_outdata(struct s5p_aes_dev *dev)
> @@ -655,6 +655,7 @@ static irqreturn_t s5p_aes_interrupt(int irq, void *dev_id)
> {
> struct platform_device *pdev = dev_id;
> struct s5p_aes_dev *dev = platform_get_drvdata(pdev);
> + struct ablkcipher_request *req;
> int err_dma_tx = 0;
> int err_dma_rx = 0;
> int err_dma_hx = 0;
> @@ -725,9 +726,10 @@ static irqreturn_t s5p_aes_interrupt(int irq, void *dev_id)
> if (err_dma_hx == 1)
> s5p_set_dma_hashdata(dev, dev->hash_sg_iter);
>
> + req = dev->req;
In this path it should not be needed, so just
s5p_aes_complete(dev->req)? At this point dev->busy is true so
s5p_aes_handle_req() will exit before starting new tasklet. Also the
interrupt is an effect of finishing work by device scheduled in last
tasklet... so obviously no tasklet should be running.
> spin_unlock_irqrestore(&dev->lock, flags);
>
> - s5p_aes_complete(dev, 0);
> + s5p_aes_complete(req, 0);
> /* Device is still busy */
> tasklet_schedule(&dev->tasklet);
> } else {
> @@ -755,8 +757,9 @@ static irqreturn_t s5p_aes_interrupt(int irq, void *dev_id)
> if (err_dma_hx == 1)
> s5p_set_dma_hashdata(dev, dev->hash_sg_iter);
>
> + req = dev->req;
Please put it before new line (so there will be new line before
unlock). Logically it should not be separated from other commands in
error path.
Best regards,
Krzysztof
