| Message ID | 20191212052841.6734-3-suwan.kim027@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | usbip: Fix infinite loop in vhci rx | expand |
On Thu, Dec 12, 2019 at 02:28:41PM +0900, Suwan Kim wrote: > If a transaction error happens in vhci_recv_ret_submit(), event > handler closes connection and changes port status to kick hub_event. > Then hub tries to flush the endpoint URBs, but that causes infinite > loop between usb_hub_flush_endpoint() and vhci_urb_dequeue() because > "vhci_priv" in vhci_urb_dequeue() was already released by > vhci_recv_ret_submit() before a transmission error occurred. Thus, > vhci_urb_dequeue() terminates early and usb_hub_flush_endpoint() > continuously calls vhci_urb_dequeue(). > > The root cause of this issue is that vhci_recv_ret_submit() > terminates early without giving back URB when transaction error > occurs in vhci_recv_ret_submit(). That causes the error URB to still > be linked at endpoint list without “vhci_priv". > > So, in the case of trasnaction error in vhci_recv_ret_submit(), ^^^ typo > unlink URB from the endpoint, insert proper error code in > urb->status and give back URB. > > Reported-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com> > Signed-off-by: Suwan Kim <suwan.kim027@gmail.com> Tested-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com> > --- > drivers/usb/usbip/vhci_rx.c | 13 +++++++++---- > 1 file changed, 9 insertions(+), 4 deletions(-) > > diff --git a/drivers/usb/usbip/vhci_rx.c b/drivers/usb/usbip/vhci_rx.c > index 33f8972ba842..dc26acad6baf 100644 > --- a/drivers/usb/usbip/vhci_rx.c > +++ b/drivers/usb/usbip/vhci_rx.c > @@ -77,16 +77,21 @@ static void vhci_recv_ret_submit(struct vhci_device *vdev, > usbip_pack_pdu(pdu, urb, USBIP_RET_SUBMIT, 0); > > /* recv transfer buffer */ > - if (usbip_recv_xbuff(ud, urb) < 0) > - return; > + if (usbip_recv_xbuff(ud, urb) < 0) { > + urb->status = -EPIPE; > + goto error; > + } > > /* recv iso_packet_descriptor */ > - if (usbip_recv_iso(ud, urb) < 0) > - return; > + if (usbip_recv_iso(ud, urb) < 0) { > + urb->status = -EPIPE; > + goto error; > + } > > /* restore the padding in iso packets */ > usbip_pad_iso(ud, urb); > > +error: > if (usbip_dbg_flag_vhci_rx) > usbip_dump_urb(urb); >
On Thu, 12 Dec 2019, Suwan Kim wrote: > If a transaction error happens in vhci_recv_ret_submit(), event > handler closes connection and changes port status to kick hub_event. > Then hub tries to flush the endpoint URBs, but that causes infinite > loop between usb_hub_flush_endpoint() and vhci_urb_dequeue() because > "vhci_priv" in vhci_urb_dequeue() was already released by > vhci_recv_ret_submit() before a transmission error occurred. Thus, > vhci_urb_dequeue() terminates early and usb_hub_flush_endpoint() > continuously calls vhci_urb_dequeue(). > > The root cause of this issue is that vhci_recv_ret_submit() > terminates early without giving back URB when transaction error > occurs in vhci_recv_ret_submit(). That causes the error URB to still > be linked at endpoint list without “vhci_priv". > > So, in the case of trasnaction error in vhci_recv_ret_submit(), > unlink URB from the endpoint, insert proper error code in > urb->status and give back URB. > > Reported-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com> > Signed-off-by: Suwan Kim <suwan.kim027@gmail.com> > --- > drivers/usb/usbip/vhci_rx.c | 13 +++++++++---- > 1 file changed, 9 insertions(+), 4 deletions(-) > > diff --git a/drivers/usb/usbip/vhci_rx.c b/drivers/usb/usbip/vhci_rx.c > index 33f8972ba842..dc26acad6baf 100644 > --- a/drivers/usb/usbip/vhci_rx.c > +++ b/drivers/usb/usbip/vhci_rx.c > @@ -77,16 +77,21 @@ static void vhci_recv_ret_submit(struct vhci_device *vdev, > usbip_pack_pdu(pdu, urb, USBIP_RET_SUBMIT, 0); > > /* recv transfer buffer */ > - if (usbip_recv_xbuff(ud, urb) < 0) > - return; > + if (usbip_recv_xbuff(ud, urb) < 0) { > + urb->status = -EPIPE; > + goto error; > + } > > /* recv iso_packet_descriptor */ > - if (usbip_recv_iso(ud, urb) < 0) > - return; > + if (usbip_recv_iso(ud, urb) < 0) { > + urb->status = -EPIPE; > + goto error; > + } -EPIPE is used for STALL. The appropriate error code for transaction error would be -EPROTO (or -EILSEQ or -ETIME, but people seem to be settling on -EPROTO). Alan Stern
On Thu, Dec 12, 2019 at 10:54:08AM -0500, Alan Stern wrote: > On Thu, 12 Dec 2019, Suwan Kim wrote: > > > If a transaction error happens in vhci_recv_ret_submit(), event > > handler closes connection and changes port status to kick hub_event. > > Then hub tries to flush the endpoint URBs, but that causes infinite > > loop between usb_hub_flush_endpoint() and vhci_urb_dequeue() because > > "vhci_priv" in vhci_urb_dequeue() was already released by > > vhci_recv_ret_submit() before a transmission error occurred. Thus, > > vhci_urb_dequeue() terminates early and usb_hub_flush_endpoint() > > continuously calls vhci_urb_dequeue(). > > > > The root cause of this issue is that vhci_recv_ret_submit() > > terminates early without giving back URB when transaction error > > occurs in vhci_recv_ret_submit(). That causes the error URB to still > > be linked at endpoint list without “vhci_priv". > > > > So, in the case of trasnaction error in vhci_recv_ret_submit(), > > unlink URB from the endpoint, insert proper error code in > > urb->status and give back URB. > > > > Reported-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com> > > Signed-off-by: Suwan Kim <suwan.kim027@gmail.com> > > --- > > drivers/usb/usbip/vhci_rx.c | 13 +++++++++---- > > 1 file changed, 9 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/usb/usbip/vhci_rx.c b/drivers/usb/usbip/vhci_rx.c > > index 33f8972ba842..dc26acad6baf 100644 > > --- a/drivers/usb/usbip/vhci_rx.c > > +++ b/drivers/usb/usbip/vhci_rx.c > > @@ -77,16 +77,21 @@ static void vhci_recv_ret_submit(struct vhci_device *vdev, > > usbip_pack_pdu(pdu, urb, USBIP_RET_SUBMIT, 0); > > > > /* recv transfer buffer */ > > - if (usbip_recv_xbuff(ud, urb) < 0) > > - return; > > + if (usbip_recv_xbuff(ud, urb) < 0) { > > + urb->status = -EPIPE; > > + goto error; > > + } > > > > /* recv iso_packet_descriptor */ > > - if (usbip_recv_iso(ud, urb) < 0) > > - return; > > + if (usbip_recv_iso(ud, urb) < 0) { > > + urb->status = -EPIPE; > > + goto error; > > + } > > -EPIPE is used for STALL. The appropriate error code for transaction > error would be -EPROTO (or -EILSEQ or -ETIME, but people seem to be > settling on -EPROTO). Thanks for the feedback. I will fix it :) Regards, Suwan Kim
diff --git a/drivers/usb/usbip/vhci_rx.c b/drivers/usb/usbip/vhci_rx.c index 33f8972ba842..dc26acad6baf 100644 --- a/drivers/usb/usbip/vhci_rx.c +++ b/drivers/usb/usbip/vhci_rx.c @@ -77,16 +77,21 @@ static void vhci_recv_ret_submit(struct vhci_device *vdev, usbip_pack_pdu(pdu, urb, USBIP_RET_SUBMIT, 0); /* recv transfer buffer */ - if (usbip_recv_xbuff(ud, urb) < 0) - return; + if (usbip_recv_xbuff(ud, urb) < 0) { + urb->status = -EPIPE; + goto error; + } /* recv iso_packet_descriptor */ - if (usbip_recv_iso(ud, urb) < 0) - return; + if (usbip_recv_iso(ud, urb) < 0) { + urb->status = -EPIPE; + goto error; + } /* restore the padding in iso packets */ usbip_pad_iso(ud, urb); +error: if (usbip_dbg_flag_vhci_rx) usbip_dump_urb(urb);
If a transaction error happens in vhci_recv_ret_submit(), event handler closes connection and changes port status to kick hub_event. Then hub tries to flush the endpoint URBs, but that causes infinite loop between usb_hub_flush_endpoint() and vhci_urb_dequeue() because "vhci_priv" in vhci_urb_dequeue() was already released by vhci_recv_ret_submit() before a transmission error occurred. Thus, vhci_urb_dequeue() terminates early and usb_hub_flush_endpoint() continuously calls vhci_urb_dequeue(). The root cause of this issue is that vhci_recv_ret_submit() terminates early without giving back URB when transaction error occurs in vhci_recv_ret_submit(). That causes the error URB to still be linked at endpoint list without “vhci_priv". So, in the case of trasnaction error in vhci_recv_ret_submit(), unlink URB from the endpoint, insert proper error code in urb->status and give back URB. Reported-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com> Signed-off-by: Suwan Kim <suwan.kim027@gmail.com> --- drivers/usb/usbip/vhci_rx.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-)