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if_bridge(4): Fix module teardown

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bridge_rtnode_zone still has outstanding allocations at the time of
destruction in the current model because all of the interface teardown
happens in a VNET_SYSUNINIT, -after- the MOD_UNLOAD has already been
processed.  The SYSUNINIT triggers destruction of the interfaces, which then
attempts to free the memory from the zone that's already been destroyed, and
we hit a panic.

Solve this by virtualizing the uma_zone we allocate the rtnodes from to fix
the ordering. bridge_rtable_fini should also take care to flush any
remaining routes that weren't taken care of when dynamic routes were flushed
in bridge_stop.

Reviewed by:	kp
Differential Revision:	https://reviews.freebsd.org/D19578
This commit is contained in:
Kyle Evans 2019-03-15 13:19:52 +00:00
parent 0204d1c793
commit a87407ff85
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=345180
1 changed files with 16 additions and 11 deletions
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27
sys/net/if_bridge.c
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@ -235,7 +235,8 @@ static eventhandler_tag bridge_detach_cookie;
int bridge_rtable_prune_period = BRIDGE_RTABLE_PRUNE_PERIOD;
uma_zone_t bridge_rtnode_zone;
VNET_DEFINE_STATIC(uma_zone_t, bridge_rtnode_zone);
#define V_bridge_rtnode_zone VNET(bridge_rtnode_zone)
static int bridge_clone_create(struct if_clone *, int, caddr_t);
static void bridge_clone_destroy(struct ifnet *);
@ -527,6 +528,9 @@ static void
vnet_bridge_init(const void *unused __unused)
{
V_bridge_rtnode_zone = uma_zcreate("bridge_rtnode",
sizeof(struct bridge_rtnode), NULL, NULL, NULL, NULL,
UMA_ALIGN_PTR, 0);
BRIDGE_LIST_LOCK_INIT();
LIST_INIT(&V_bridge_list);
V_bridge_cloner = if_clone_simple(bridge_name,
@ -542,6 +546,7 @@ vnet_bridge_uninit(const void *unused __unused)
if_clone_detach(V_bridge_cloner);
V_bridge_cloner = NULL;
BRIDGE_LIST_LOCK_DESTROY();
uma_zdestroy(V_bridge_rtnode_zone);
}
VNET_SYSUNINIT(vnet_bridge_uninit, SI_SUB_PSEUDO, SI_ORDER_ANY,
vnet_bridge_uninit, NULL);
@ -552,9 +557,6 @@ bridge_modevent(module_t mod, int type, void *data)
switch (type) {
case MOD_LOAD:
bridge_rtnode_zone = uma_zcreate("bridge_rtnode",
sizeof(struct bridge_rtnode), NULL, NULL, NULL, NULL,
UMA_ALIGN_PTR, 0);
bridge_dn_p = bridge_dummynet;
bridge_detach_cookie = EVENTHANDLER_REGISTER(
ifnet_departure_event, bridge_ifdetach, NULL,
@ -563,7 +565,6 @@ bridge_modevent(module_t mod, int type, void *data)
case MOD_UNLOAD:
EVENTHANDLER_DEREGISTER(ifnet_departure_event,
bridge_detach_cookie);
uma_zdestroy(bridge_rtnode_zone);
bridge_dn_p = NULL;
break;
default:
@ -730,6 +731,9 @@ bridge_clone_destroy(struct ifnet *ifp)
bridge_delete_span(sc, bif);
}
/* Tear down the routing table. */
bridge_rtable_fini(sc);
BRIDGE_UNLOCK(sc);
callout_drain(&sc->sc_brcallout);
@ -742,9 +746,6 @@ bridge_clone_destroy(struct ifnet *ifp)
ether_ifdetach(ifp);
if_free(ifp);
/* Tear down the routing table. */
bridge_rtable_fini(sc);
BRIDGE_LOCK_DESTROY(sc);
free(sc, M_DEVBUF);
}
@ -2669,7 +2670,7 @@ bridge_rtupdate(struct bridge_softc *sc, const uint8_t *dst, uint16_t vlan,
* initialize the expiration time and Ethernet
* address.
*/
brt = uma_zalloc(bridge_rtnode_zone, M_NOWAIT | M_ZERO);
brt = uma_zalloc(V_bridge_rtnode_zone, M_NOWAIT | M_ZERO);
if (brt == NULL)
return (ENOMEM);
@ -2682,7 +2683,7 @@ bridge_rtupdate(struct bridge_softc *sc, const uint8_t *dst, uint16_t vlan,
brt->brt_vlan = vlan;
if ((error = bridge_rtnode_insert(sc, brt)) != 0) {
uma_zfree(bridge_rtnode_zone, brt);
uma_zfree(V_bridge_rtnode_zone, brt);
return (error);
}
brt->brt_dst = bif;
@ -2766,11 +2767,14 @@ bridge_timer(void *arg)
BRIDGE_LOCK_ASSERT(sc);
/* Destruction of rtnodes requires a proper vnet context */
CURVNET_SET(sc->sc_ifp->if_vnet);
bridge_rtage(sc);
if (sc->sc_ifp->if_drv_flags & IFF_DRV_RUNNING)
callout_reset(&sc->sc_brcallout,
bridge_rtable_prune_period * hz, bridge_timer, sc);
CURVNET_RESTORE();
}
/*
@ -2886,6 +2890,7 @@ bridge_rtable_fini(struct bridge_softc *sc)
KASSERT(sc->sc_brtcnt == 0,
("%s: %d bridge routes referenced", __func__, sc->sc_brtcnt));
bridge_rtflush(sc, 1);
free(sc->sc_rthash, M_DEVBUF);
}
@ -3028,7 +3033,7 @@ bridge_rtnode_destroy(struct bridge_softc *sc, struct bridge_rtnode *brt)
LIST_REMOVE(brt, brt_list);
sc->sc_brtcnt--;
brt->brt_dst->bif_addrcnt--;
uma_zfree(bridge_rtnode_zone, brt);
uma_zfree(V_bridge_rtnode_zone, brt);
}
/*