From: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx> commit e6cebcc27519dcf1652e604c73b9fd4f416987c0 upstream. For the STOP and RESET commands, only send the channel disconnect status -ENOTCONN if client driver is available. Otherwise, it will result in null pointer dereference. Cc: <stable@xxxxxxxxxxxxxxx> # 5.19 Fixes: e827569062a8 ("bus: mhi: ep: Add support for processing command rings") Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx> Reviewed-by: Jeffrey Hugo <quic_jhugo@xxxxxxxxxxx> Link: https://lore.kernel.org/r/20221228161704.255268-4-manivannan.sadhasivam@xxxxxxxxxx Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/bus/mhi/ep/main.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) --- a/drivers/bus/mhi/ep/main.c +++ b/drivers/bus/mhi/ep/main.c @@ -196,9 +196,11 @@ static int mhi_ep_process_cmd_ring(struc mhi_ep_mmio_disable_chdb(mhi_cntrl, ch_id); /* Send channel disconnect status to client drivers */ - result.transaction_status = -ENOTCONN; - result.bytes_xferd = 0; - mhi_chan->xfer_cb(mhi_chan->mhi_dev, &result); + if (mhi_chan->xfer_cb) { + result.transaction_status = -ENOTCONN; + result.bytes_xferd = 0; + mhi_chan->xfer_cb(mhi_chan->mhi_dev, &result); + } /* Set channel state to STOP */ mhi_chan->state = MHI_CH_STATE_STOP; @@ -228,9 +230,11 @@ static int mhi_ep_process_cmd_ring(struc mhi_ep_ring_reset(mhi_cntrl, ch_ring); /* Send channel disconnect status to client driver */ - result.transaction_status = -ENOTCONN; - result.bytes_xferd = 0; - mhi_chan->xfer_cb(mhi_chan->mhi_dev, &result); + if (mhi_chan->xfer_cb) { + result.transaction_status = -ENOTCONN; + result.bytes_xferd = 0; + mhi_chan->xfer_cb(mhi_chan->mhi_dev, &result); + } /* Set channel state to DISABLED */ mhi_chan->state = MHI_CH_STATE_DISABLED;