From 6323991c32b50145b2410f193aa0685e74466053 Mon Sep 17 00:00:00 2001 From: hselasky Date: Sat, 29 Aug 2015 06:11:50 +0000 Subject: MFC r286799: Fix race in USB PF which can happen if we stop tracing exactly when the kernel is tapping an USB transfer. This leads to a NULL pointer access. The solution is to only trace while the USB bus lock is locked. --- sys/dev/usb/usb_pf.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'sys/dev/usb/usb_pf.c') diff --git a/sys/dev/usb/usb_pf.c b/sys/dev/usb/usb_pf.c index 27ab5f7..8c47e79 100644 --- a/sys/dev/usb/usb_pf.c +++ b/sys/dev/usb/usb_pf.c @@ -220,7 +220,13 @@ usbpf_clone_destroy(struct if_clone *ifc, struct ifnet *ifp) ubus = ifp->if_softc; unit = ifp->if_dunit; + /* + * Lock USB before clearing the "ifp" pointer, to avoid + * clearing the pointer in the middle of a TAP operation: + */ + USB_BUS_LOCK(ubus); ubus->ifp = NULL; + USB_BUS_UNLOCK(ubus); bpfdetach(ifp); if_detach(ifp); if_free(ifp); -- cgit v1.1