On Sun, 25 Jul 2021 16:42:49 +0900 Yasushi SHOJI <yasushi.shoji@xxxxxxxxx> wrote: > Hi Pavel, > Hi, Yasushi! > Apologize for the late reply. > > Since 6bd3d80d1f019cef, my Microchip CAN Analyzer stopped working, > more precisely I can't capture any data with it and repeated messages > from the driver flod the syslog. I usually use the Debian kernel image > and linux 5.10.46-2 migrated to unstable on July 20th. I noticed my > device stopped working a few days later but didn't have time to > bisect. > > Does your device work with the patch? > Does the patch work on the main line? > I don't have this device, I just fixed this syzbot bug report: https://syzkaller.appspot.com/bug?id=c94c1c23e829d5ac97995d51219f0c5a0cd1fa54. I think, I found the root case. In this patch I saved dma_buff to local variable and then to array, but forgot to assign it to urb->transfer_buf. This log [ 33.862175] DMAR: [DMA Write] Request device [00:14.0] PASID ffffffff fault addr 0 [fault reason 05] PTE Write access is not set points exactly to this problem. Can You try the following patch? diff --git a/drivers/net/can/usb/mcba_usb.c b/drivers/net/can/usb/mcba_usb.c index a45865bd7254..a1a154c08b7f 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, I've added Marc to this discussion, I believe, he can help us, since he is CAN maintainer. I am sorry for breaking your device :( > I've posted some report with my hardware configuration at debian > mailing list: https://bugs.debian.org/990850 > > Please let me know if you need any more information. > > Best, > -- > yashi With regards, Pavel Skripkin
