Date: Sat, 29 Aug 2015 06:11:51 +0000 (UTC) From: Hans Petter Selasky <hselasky@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-10@freebsd.org Subject: svn commit: r287272 - stable/10/sys/dev/usb Message-ID: <201508290611.t7T6Bpto027107@repo.freebsd.org>
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Author: hselasky Date: Sat Aug 29 06:11:50 2015 New Revision: 287272 URL: https://svnweb.freebsd.org/changeset/base/287272 Log: 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. Modified: stable/10/sys/dev/usb/usb_pf.c stable/10/sys/dev/usb/usb_transfer.c Directory Properties: stable/10/ (props changed) Modified: stable/10/sys/dev/usb/usb_pf.c ============================================================================== --- stable/10/sys/dev/usb/usb_pf.c Sat Aug 29 06:07:55 2015 (r287271) +++ stable/10/sys/dev/usb/usb_pf.c Sat Aug 29 06:11:50 2015 (r287272) @@ -220,7 +220,13 @@ usbpf_clone_destroy(struct if_clone *ifc 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); Modified: stable/10/sys/dev/usb/usb_transfer.c ============================================================================== --- stable/10/sys/dev/usb/usb_transfer.c Sat Aug 29 06:07:55 2015 (r287271) +++ stable/10/sys/dev/usb/usb_transfer.c Sat Aug 29 06:11:50 2015 (r287272) @@ -2381,8 +2381,11 @@ usbd_callback_wrapper(struct usb_xfer_qu } #if USB_HAVE_PF - if (xfer->usb_state != USB_ST_SETUP) + if (xfer->usb_state != USB_ST_SETUP) { + USB_BUS_LOCK(info->bus); usbpf_xfertap(xfer, USBPF_XFERTAP_DONE); + USB_BUS_UNLOCK(info->bus); + } #endif /* call processing routine */ (xfer->callback) (xfer, xfer->error);
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