From 96d87bdda3919bb16f754b3d3fd1227e1f38f13c Mon Sep 17 00:00:00 2001 From: Gerd Hoffmann Date: Thu, 2 Feb 2017 12:36:12 +0100 Subject: [PATCH] xhci: guard xhci_kick_epctx against recursive calls Track xhci_kick_epctx processing being active in a variable. Check the variable before calling xhci_kick_epctx from xhci_kick_ep. Add an assert to make sure we don't call recursively into xhci_kick_epctx. Cc: 1653384@bugs.launchpad.net Fixes: 94b037f2a451b3dc855f9f2c346e5049a361bd55 Reported-by: Fabian Lesniak Signed-off-by: Gerd Hoffmann Message-id: 1486035372-3621-1-git-send-email-kraxel@redhat.com Message-id: 1485790607-31399-5-git-send-email-kraxel@redhat.com --- hw/usb/hcd-xhci.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/hw/usb/hcd-xhci.c b/hw/usb/hcd-xhci.c index f89d8dafba..1878dad2ce 100644 --- a/hw/usb/hcd-xhci.c +++ b/hw/usb/hcd-xhci.c @@ -390,6 +390,7 @@ struct XHCIEPContext { dma_addr_t pctx; unsigned int max_psize; uint32_t state; + uint32_t kick_active; /* streams */ unsigned int max_pstreams; @@ -2131,6 +2132,9 @@ static void xhci_kick_ep(XHCIState *xhci, unsigned int slotid, return; } + if (epctx->kick_active) { + return; + } xhci_kick_epctx(epctx, streamid); } @@ -2146,6 +2150,7 @@ static void xhci_kick_epctx(XHCIEPContext *epctx, unsigned int streamid) int i; trace_usb_xhci_ep_kick(epctx->slotid, epctx->epid, streamid); + assert(!epctx->kick_active); /* If the device has been detached, but the guest has not noticed this yet the 2 above checks will succeed, but we must NOT continue */ @@ -2217,6 +2222,7 @@ static void xhci_kick_epctx(XHCIEPContext *epctx, unsigned int streamid) } assert(ring->dequeue != 0); + epctx->kick_active++; while (1) { length = xhci_ring_chain_length(xhci, ring); if (length <= 0) { @@ -2253,6 +2259,7 @@ static void xhci_kick_epctx(XHCIEPContext *epctx, unsigned int streamid) break; } } + epctx->kick_active--; ep = xhci_epid_to_usbep(epctx); if (ep) {