Re: [PATCH] dmaengine: ti-dma-crossbar: Fix possible race condition with dma_inuse

From: Vinod Koul
Date: Thu Sep 21 2017 - 13:28:10 EST


On Thu, Sep 21, 2017 at 02:35:32PM +0300, Peter Ujfalusi wrote:
> When looking for unused xbar_out lane we should also protect the set_bit()
> call with the same mutex to protect against concurrent threads picking the
> same ID.

Applied, thanks

Just a note, somehow the patches from you only are getting mangled for me.
Curiously, the ones in patchworks are fine and I used to apply that, not sure
what mail servers at our work places are doing!!

>
> Fixes: ec9bfa1e1a796 ("dmaengine: ti-dma-crossbar: dra7: Use bitops instead of idr")
> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@xxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> ---
> drivers/dma/ti-dma-crossbar.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/dma/ti-dma-crossbar.c b/drivers/dma/ti-dma-crossbar.c
> index 10ef9d5d5a66..7df910e7c348 100644
> --- a/drivers/dma/ti-dma-crossbar.c
> +++ b/drivers/dma/ti-dma-crossbar.c
> @@ -262,13 +262,14 @@ static void *ti_dra7_xbar_route_allocate(struct of_phandle_args *dma_spec,
> mutex_lock(&xbar->mutex);
> map->xbar_out = find_first_zero_bit(xbar->dma_inuse,
> xbar->dma_requests);
> - mutex_unlock(&xbar->mutex);
> if (map->xbar_out == xbar->dma_requests) {
> + mutex_unlock(&xbar->mutex);
> dev_err(&pdev->dev, "Run out of free DMA requests\n");
> kfree(map);
> return ERR_PTR(-ENOMEM);
> }
> set_bit(map->xbar_out, xbar->dma_inuse);
> + mutex_unlock(&xbar->mutex);
>
> map->xbar_in = (u16)dma_spec->args[0];
>
> --
> 2.14.1
>
>
> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
>
>

--
~Vinod