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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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