[src/trunk]: src/sys/dev/pci Fix a possible deadlock in iavf(4)

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

details:   https://anonhg.NetBSD.org/src/rev/24cfad1156b3
branches:  trunk
changeset: 975971:24cfad1156b3
user:      yamaguchi <yamaguchi%NetBSD.org@localhost>
date:      Thu Sep 10 03:20:08 2020 +0000

description:
Fix a possible deadlock in iavf(4)

diffstat:

 sys/dev/pci/if_iavf.c |  14 ++++++++++----
 1 files changed, 10 insertions(+), 4 deletions(-)

diffs (48 lines):

diff -r ec119d91560a -r 24cfad1156b3 sys/dev/pci/if_iavf.c
--- a/sys/dev/pci/if_iavf.c     Thu Sep 10 03:02:36 2020 +0000
+++ b/sys/dev/pci/if_iavf.c     Thu Sep 10 03:20:08 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: if_iavf.c,v 1.4 2020/09/09 00:56:17 yamaguchi Exp $    */
+/*     $NetBSD: if_iavf.c,v 1.5 2020/09/10 03:20:08 yamaguchi Exp $    */
 
 /*
  * Copyright (c) 2013-2015, Intel Corporation
@@ -75,7 +75,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: if_iavf.c,v 1.4 2020/09/09 00:56:17 yamaguchi Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if_iavf.c,v 1.5 2020/09/10 03:20:08 yamaguchi Exp $");
 
 #include <sys/param.h>
 #include <sys/types.h>
@@ -3523,6 +3523,7 @@
        struct ether_multistep step;
        struct ifnet *ifp = &ec->ec_if;
        struct vlanid_list *vlanidp;
+       uint8_t enaddr_prev[ETHER_ADDR_LEN], enaddr_next[ETHER_ADDR_LEN];
 
        KASSERT(mutex_owned(&sc->sc_cfg_lock));
 
@@ -3550,14 +3551,19 @@
        ETHER_UNLOCK(ec);
 
        if (memcmp(sc->sc_enaddr, sc->sc_enaddr_reset, ETHER_ADDR_LEN) != 0) {
+               memcpy(enaddr_prev, sc->sc_enaddr_reset, sizeof(enaddr_prev));
+               memcpy(enaddr_next, sc->sc_enaddr, sizeof(enaddr_next));
                log(LOG_INFO, "%s: Ethernet address changed to %s\n",
-                   ifp->if_xname, ether_sprintf(sc->sc_enaddr));
+                   ifp->if_xname, ether_sprintf(enaddr_next));
+
+               mutex_exit(&sc->sc_cfg_lock);
                IFNET_LOCK(ifp);
                kpreempt_disable();
                /*XXX we need an API to change ethernet address. */
-               iavf_replace_lla(ifp, sc->sc_enaddr_reset, sc->sc_enaddr);
+               iavf_replace_lla(ifp, enaddr_prev, enaddr_next);
                kpreempt_enable();
                IFNET_UNLOCK(ifp);
+               mutex_enter(&sc->sc_cfg_lock);
        }
 
        sc->sc_resetting = false;