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 achive 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
inialize 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.
[ 33.862175] DMAR: [DMA Write] Request device [00:14.0] PASID ffffffff fault addr 0 [fault reason 05] PTE Write access is not set
Bug report: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=990850
Reported-by: Yasushi SHOJI <[email protected]>
Fixes: 91c02557174b ("can: mcba_usb: fix memory leak in mcba_usb")
Signed-off-by: Pavel Skripkin <[email protected]>
---
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 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,
--
2.32.0
Hi Pavel,
I've tested this patch on top of v5.14-rc2. All good.
Tested-by: Yasushi SHOJI <[email protected]>
Some nitpicks.
On Sun, Jul 25, 2021 at 7:36 PM Pavel Skripkin <[email protected]> wrote:
>
> 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 achive it, I passed local stack
achieve
> 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
> inialize urb->transfer_dma with variable passed to usb_alloc_coherent().
initialize
> 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.
>
> [ 33.862175] DMAR: [DMA Write] Request device [00:14.0] PASID ffffffff fault addr 0 [fault reason 05] PTE Write access is not set
>
> Bug report: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=990850
>
> Reported-by: Yasushi SHOJI <[email protected]>
> Fixes: 91c02557174b ("can: mcba_usb: fix memory leak in mcba_usb")
> Signed-off-by: Pavel Skripkin <[email protected]>
> ---
> 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 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,
> --
> 2.32.0
Pavel, thanks again for your quick fix. :-)
Best,
--
yashi
On 25.07.2021 22:27:37, Yasushi SHOJI wrote:
> Hi Pavel,
>
> I've tested this patch on top of v5.14-rc2. All good.
>
> Tested-by: Yasushi SHOJI <[email protected]>
>
> Some nitpicks.
>
> On Sun, Jul 25, 2021 at 7:36 PM Pavel Skripkin <[email protected]> wrote:
> >
> > 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 achive it, I passed local stack
>
> achieve
>
> > 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
> > inialize urb->transfer_dma with variable passed to usb_alloc_coherent().
>
> initialize
Fixed while applying.
Thanks,
Marc
--
Pengutronix e.K. | Marc Kleine-Budde |
Embedded Linux | https://www.pengutronix.de |
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