From: Prasad J Pandit <p...@fedoraproject.org>
While servicing OHCI transfer descriptors(TD), ohci_service_iso_td
retires a TD if it has passed its time frame. It does not check if
the TD was already processed once and holds an error code in TD_CC.
It may happen if the TD list has a loop. Add check to avoid an
infinite loop condition.
Signed-off-by: Prasad J Pandit <p...@fedoraproject.org>
Reviewed-by: Li Qiang <liq...@gmail.com>
Message-id: 20200915182259.68522-3-ppan...@redhat.com
Signed-off-by: Gerd Hoffmann <kra...@redhat.com>
---
hw/usb/hcd-ohci.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/hw/usb/hcd-ohci.c b/hw/usb/hcd-ohci.c
index 9dc59101f958..8b912e95d31d 100644
--- a/hw/usb/hcd-ohci.c
+++ b/hw/usb/hcd-ohci.c
@@ -691,6 +691,10 @@ static int ohci_service_iso_td(OHCIState *ohci, struct
ohci_ed *ed,
the next ISO TD of the same ED */
trace_usb_ohci_iso_td_relative_frame_number_big(relative_frame_number,
frame_count);
+ if (OHCI_CC_DATAOVERRUN == OHCI_BM(iso_td.flags, TD_CC)) {
+ /* avoid infinite loop */
+ return 1;
+ }
OHCI_SET_BM(iso_td.flags, TD_CC, OHCI_CC_DATAOVERRUN);
ed->head &= ~OHCI_DPTR_MASK;
ed->head |= (iso_td.next & OHCI_DPTR_MASK);
--
2.27.0
