From 51cb8dbf13246a0b144bff01d7d617efe550a055 Mon Sep 17 00:00:00 2001 From: Logan Gunthorpe Date: Tue, 19 Feb 2019 12:56:36 -0700 Subject: [PATCH] NTB: ntb_transport: Ensure qp->tx_mw_dma_addr is initaliazed Dan Carpenter's static checker reported: drivers/ntb/ntb_transport.c:1926 ntb_transport_create_queue() error: we previously assumed 'qp->tx_dma_chan' could be null (see line 1872) This is because the tx_mw_dma_addr is uninitialized in this function and may be incorrectly released using a NULL DMA channel. In practice this bug will not likely be seen. I'd guess you could hit this if you loaded ntb_netdev with use_dma=True, then unloaded it and loaded it again after setting the module parameter to use_dma=False. To fix this, we simply ensure that tx_mw_dma_addr is always initialized to zero. This is the safest in case any other part of the code operates on it if it is non-zero. Fixes: c59666bb32b9 ("NTB: ntb_transport: Ensure the destination buffer is mapped for TX DMA") Signed-off-by: Logan Gunthorpe Cc: Dan Carpenter Signed-off-by: Jon Mason --- drivers/ntb/ntb_transport.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c index d4f39ba1d976..99033228dccb 100644 --- a/drivers/ntb/ntb_transport.c +++ b/drivers/ntb/ntb_transport.c @@ -1869,6 +1869,7 @@ ntb_transport_create_queue(void *data, struct device *client_dev, qp->rx_dma_chan = NULL; } + qp->tx_mw_dma_addr = 0; if (qp->tx_dma_chan) { qp->tx_mw_dma_addr = dma_map_resource(qp->tx_dma_chan->device->dev,