From 1be90ebecc95b09a2ee5af3f60c412b45a766c4f Mon Sep 17 00:00:00 2001 From: Prasad J Pandit Date: Tue, 15 Sep 2020 23:52:59 +0530 Subject: [PATCH] hw: usb: hcd-ohci: check for processed TD before retire 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 Reviewed-by: Li Qiang Message-id: 20200915182259.68522-3-ppandit@redhat.com Signed-off-by: Gerd Hoffmann --- 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 9dc59101f9..8b912e95d3 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); -- 2.11.4.GIT