[src/trunk]: src/sys/dev/usb usbnet: Ensure ifp->if_softc is initialized _bef...

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/b1fe1ed322d6
branches:  trunk
changeset: 362486:b1fe1ed322d6
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Thu Mar 03 05:47:14 2022 +0000

description:
usbnet: Ensure ifp->if_softc is initialized _before_ publishing ifp.

Otherwise other parts of the system might start using ifp the moment
we if_register it, and trip over null if_softc.

diffstat:

 sys/dev/usb/usbnet.c |  11 +++++++----
 1 files changed, 7 insertions(+), 4 deletions(-)

diffs (61 lines):

diff -r ea1795b888ed -r b1fe1ed322d6 sys/dev/usb/usbnet.c
--- a/sys/dev/usb/usbnet.c      Thu Mar 03 05:47:06 2022 +0000
+++ b/sys/dev/usb/usbnet.c      Thu Mar 03 05:47:14 2022 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: usbnet.c,v 1.47 2022/03/03 05:47:06 riastradh Exp $    */
+/*     $NetBSD: usbnet.c,v 1.48 2022/03/03 05:47:14 riastradh Exp $    */
 
 /*
  * Copyright (c) 2019 Matthew R. Green
@@ -31,7 +31,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: usbnet.c,v 1.47 2022/03/03 05:47:06 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: usbnet.c,v 1.48 2022/03/03 05:47:14 riastradh Exp $");
 
 #include <sys/param.h>
 #include <sys/kernel.h>
@@ -80,6 +80,7 @@
        bool                    unp_dying;
        bool                    unp_stopping;
        bool                    unp_attached;
+       bool                    unp_ifp_attached;
        bool                    unp_link;
 
        int                     unp_refcnt;
@@ -1492,7 +1493,9 @@
        struct ifnet * const ifp = usbnet_ifp(un);
 
        KASSERT(unp->unp_attached);
+       KASSERT(!unp->unp_ifp_attached);
 
+       ifp->if_softc = un;
        strlcpy(ifp->if_xname, device_xname(un->un_dev), IFNAMSIZ);
        ifp->if_flags = if_flags;
        ifp->if_extflags = IFEF_MPSAFE | if_extflags;
@@ -1511,6 +1514,7 @@
        if (ifp->_if_input == NULL)
                ifp->if_percpuq = if_percpuq_create(ifp);
        if_register(ifp);
+       unp->unp_ifp_attached = true;
 
        /*
         * If ethernet address is all zero, skip ether_ifattach() and
@@ -1528,7 +1532,6 @@
 
        /* Now ready, and attached. */
        IFQ_SET_READY(&ifp->if_snd);
-       ifp->if_softc = un;
 
        usbd_add_drv_event(USB_EVENT_DRIVER_ATTACH, un->un_udev, un->un_dev);
 
@@ -1584,7 +1587,7 @@
                mii_detach(mii, MII_PHY_ANY, MII_OFFSET_ANY);
                ifmedia_fini(&mii->mii_media);
        }
-       if (ifp->if_softc) {
+       if (unp->unp_ifp_attached) {
                if (!usbnet_empty_eaddr(un))
                        ether_ifdetach(ifp);
                else