Hi Simon-san,
>
> On Fri, Jan 30, 2015 at 03:58:23PM +0900, Yoshihiro Shimoda wrote:
> > This patch fixes an issue that the following commit causes NULL
> > pointer dereference in dma_release_channel().
> > "usb: renesas_usbhs: add support for requesting DT DMA"
> > (commit id abd2dbf6bb1b5f3a03a8c76b1a8879da1dd30caa)
> >
> > The usbhsf_dma_init_dt() should set fifo->{t,r}x_chan to NULL if
> > dma_request_slave_channel_reason() returns IS_ERR value.
> > Otherwise, usbhsf_dma_quit() will call dma_release_channel(), and then
> > NULL pointer dereference happens.
> >
> > Reported-by: Simon Horman <horms@xxxxxxxxxxxx>
> > Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
>
> I have tested this on the lager and koelsch boards using
> shmobile_defconfig and next-20150129 as a base. The environment
> where I originally observed the problem.
>
> Tested-by: Simon Horman <horms+renesas@xxxxxxxxxxxx>
Thank you for the test!
Best regards,
Yoshihiro Shimoda
> > ---
> > This patch is based on Felipe's usb.git / testing/next branch.
> > (commit id =7db3990cb707ff91cd6507d53a0a730afe97)
> >
> > drivers/usb/renesas_usbhs/fifo.c | 4 ++++
> > 1 file changed, 4 insertions(+)
> >
> > diff --git a/drivers/usb/renesas_usbhs/fifo.c b/drivers/usb/renesas_usbhs/fifo.c
> > index 4c086b1..d891bff 100644
> > --- a/drivers/usb/renesas_usbhs/fifo.c
> > +++ b/drivers/usb/renesas_usbhs/fifo.c
> > @@ -1072,7 +1072,11 @@ static void usbhsf_dma_init_pdev(struct usbhs_fifo *fifo)
> > static void usbhsf_dma_init_dt(struct device *dev, struct usbhs_fifo *fifo)
> > {
> > fifo->tx_chan = dma_request_slave_channel_reason(dev, "tx");
> > + if (IS_ERR(fifo->tx_chan))
> > + fifo->tx_chan = NULL;
> > fifo->rx_chan = dma_request_slave_channel_reason(dev, "rx");
> > + if (IS_ERR(fifo->rx_chan))
> > + fifo->rx_chan = NULL;
> > }
> >
> > static void usbhsf_dma_init(struct usbhs_priv *priv,
> > --
> > 1.7.9.5
> >
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