Re: [PATCH v2] mhi: Fix double dma free

[Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>]

On Tue, Feb 09, 2021 at 07:11:04PM +0100, Loic Poulain wrote:
> mhi_deinit_chan_ctxt functionthat takes care of unitializing channel
> resources, including unmapping coherent MHI areas, can be called
> from different path in case of controller unregistering/removal:
>  - From a client driver remove callback, via mhi_unprepare_channel
>  - From mhi_driver_remove that unitialize all channels
> 
> mhi_driver_remove()
> |-> driver->remove()
> |    |-> mhi_unprepare_channel()
> |        |-> mhi_deinit_chan_ctxt()
> |...
> |-> mhi_deinit_chan_ctxt()
> 
> This leads to double dma freeing...
> 
> Fix that by preventing deinit for already uninitialized channel.
> 
> Fixes: a7f422f2f89e ("bus: mhi: Fix channel close issue on driver remove")
> Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
> Reported-by: Kalle Valo <kvalo@codeaurora.org>
> Tested-by: Kalle Valo <kvalo@codeaurora.org>

Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

Thanks,
Mani

> ---
>  v2: add Fixes tag
> 
>  drivers/bus/mhi/core/init.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
> index aa575d3..be4eebb 100644
> --- a/drivers/bus/mhi/core/init.c
> +++ b/drivers/bus/mhi/core/init.c
> @@ -557,6 +557,9 @@ void mhi_deinit_chan_ctxt(struct mhi_controller *mhi_cntrl,
>  	tre_ring = &mhi_chan->tre_ring;
>  	chan_ctxt = &mhi_cntrl->mhi_ctxt->chan_ctxt[mhi_chan->chan];
>  
> +	if (!chan_ctxt->rbase) /* Already uninitialized */
> +		return;
> +
>  	mhi_free_coherent(mhi_cntrl, tre_ring->alloc_size,
>  			  tre_ring->pre_aligned, tre_ring->dma_handle);
>  	vfree(buf_ring->base);
> -- 
> 2.7.4
>