From fc43fb69a7af92839551f99c1a96a37b77b3ae7a Mon Sep 17 00:00:00 2001 From: Pavel Skripkin Date: Sun, 25 Jul 2021 13:36:30 +0300 Subject: [PATCH] can: mcba_usb_start(): add missing urb->transfer_dma initialization Yasushi reported, that his Microchip CAN Analyzer stopped working since commit 91c02557174b ("can: mcba_usb: fix memory leak in mcba_usb"). The problem was in missing urb->transfer_dma initialization. In my previous patch to this driver I refactored mcba_usb_start() code to avoid leaking usb coherent buffers. To archive it, I passed local stack variable to usb_alloc_coherent() and then saved it to private array to correctly free all coherent buffers on ->close() call. But I forgot to initialize urb->transfer_dma with variable passed to usb_alloc_coherent(). All of this was causing device to not work, since dma addr 0 is not valid and following log can be found on bug report page, which points exactly to problem described above. | DMAR: [DMA Write] Request device [00:14.0] PASID ffffffff fault addr 0 [fault reason 05] PTE Write access is not set Fixes: 91c02557174b ("can: mcba_usb: fix memory leak in mcba_usb") Link: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=990850 Link: https://lore.kernel.org/r/20210725103630.23864-1-paskripkin@gmail.com Cc: linux-stable Reported-by: Yasushi SHOJI Signed-off-by: Pavel Skripkin Tested-by: Yasushi SHOJI [mkl: fixed typos in commit message - thanks Yasushi SHOJI] Signed-off-by: Marc Kleine-Budde --- drivers/net/can/usb/mcba_usb.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/net/can/usb/mcba_usb.c b/drivers/net/can/usb/mcba_usb.c index a45865b..a1a154c 100644 --- a/drivers/net/can/usb/mcba_usb.c +++ b/drivers/net/can/usb/mcba_usb.c @@ -653,6 +653,8 @@ static int mcba_usb_start(struct mcba_priv *priv) break; } + urb->transfer_dma = buf_dma; + usb_fill_bulk_urb(urb, priv->udev, usb_rcvbulkpipe(priv->udev, MCBA_USB_EP_IN), buf, MCBA_USB_RX_BUFF_SIZE, -- 2.7.4