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SubjectRe: [PATCH 3.2 071/115] usb: renesas_usbhs: fix to avoid using a disabled ep in usbhsg_queue_done()
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On Wed, 2016-04-27 at 01:02 +0200, Ben Hutchings wrote:
> 3.2.80-rc1 review patch.  If anyone has any objections, please let me know.

I'm dropping this as it depends on other changes to renesas_usbhs.

Ben.

> ------------------
>
> From: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
>
> commit 4fccb0767fdbdb781a9c5b5c15ee7b219443c89d upstream.
>
> This patch fixes an issue that usbhsg_queue_done() may cause kernel
> panic when dma callback is running and usb_ep_disable() is called
> by interrupt handler. (Especially, we can reproduce this issue using
> g_audio with usb-dmac driver.)
>
> For example of a flow:
>  usbhsf_dma_complete (on tasklet)
>   --> usbhsf_pkt_handler (on tasklet)
>    --> usbhsg_queue_done (on tasklet)
>     *** interrupt happened and usb_ep_disable() is called ***
>     --> usbhsg_queue_pop (on tasklet)
>      Then, oops happened.
>
> Fixes: e73a989 ("usb: renesas_usbhs: add DMAEngine support")
> Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
> Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
> ---
>  drivers/usb/renesas_usbhs/mod_gadget.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
>
> --- a/drivers/usb/renesas_usbhs/mod_gadget.c
> +++ b/drivers/usb/renesas_usbhs/mod_gadget.c
> @@ -146,10 +146,14 @@ static void usbhsg_queue_done(struct usb
>   struct usbhs_pipe *pipe = pkt->pipe;
>   struct usbhsg_uep *uep = usbhsg_pipe_to_uep(pipe);
>   struct usbhsg_request *ureq = usbhsg_pkt_to_ureq(pkt);
> + unsigned long flags;
>  
>   ureq->req.actual = pkt->actual;
>  
> - usbhsg_queue_pop(uep, ureq, 0);
> + usbhs_lock(priv, flags);
> + if (uep)
> + __usbhsg_queue_pop(uep, ureq, 0);
> + usbhs_unlock(priv, flags);
>  }
>  
>  static void usbhsg_queue_push(struct usbhsg_uep *uep,
>
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--
Ben Hutchings
All extremists should be taken out and shot.[unhandled content-type:application/pgp-signature]
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