On Mon, Dec 11, 2023 at 02:42:52PM +0800, Qiang Yu wrote:
> Ensure read and write locks for the channel are not taken in succession by
> dropping the read lock from parse_xfer_event() such that a callback given
> to client can potentially queue buffers and acquire the write lock in that
> process. Any queueing of buffers should be done without channel read lock
> acquired as it can result in multiple locks and a soft lockup.
>
Cc: <stable@xxxxxxxxxxxxxxx> # 5.7
Fixes: 1d3173a3bae7 ("bus: mhi: core: Add support for processing events from client device")
> Signed-off-by: Qiang Yu <quic_qianyu@xxxxxxxxxxx>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
- Mani
> ---
> drivers/bus/mhi/host/main.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/drivers/bus/mhi/host/main.c b/drivers/bus/mhi/host/main.c
> index 32021fe..25f98d6 100644
> --- a/drivers/bus/mhi/host/main.c
> +++ b/drivers/bus/mhi/host/main.c
> @@ -642,6 +642,8 @@ static int parse_xfer_event(struct mhi_controller *mhi_cntrl,
> mhi_del_ring_element(mhi_cntrl, tre_ring);
> local_rp = tre_ring->rp;
>
> + read_unlock_bh(&mhi_chan->lock);
> +
> /* notify client */
> mhi_chan->xfer_cb(mhi_chan->mhi_dev, &result);
>
> @@ -667,6 +669,8 @@ static int parse_xfer_event(struct mhi_controller *mhi_cntrl,
> kfree(buf_info->cb_buf);
> }
> }
> +
> + read_lock_bh(&mhi_chan->lock);
> }
> break;
> } /* CC_EOT */
> --
> 2.7.4
>
>
--
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