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iflib: call ether_ifdetach and netmap_detach before stop

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From Jake:
Calling ether_ifdetach after iflib_stop leads to a potential race where
a stale ifp pointer can remain in the route entry list for IPv6 traffic.
This will potentially cause a page fault or other system instability if
the ifp pointer is accessed.

Move both iflib_netmap_detach and ether_ifdetach to be called prior to
iflib_stop. This avoids the race above, and helps ensure that other ifp
references are removed before stopping the interface.

Submitted by:	Jacob Keller <jacob.e.keller@intel.com>
Reviewed by:	erj@, gallatin@, jhb@
MFC after:	3 days
Sponsored by:	Intel Corporation
Differential Revision:	https://reviews.freebsd.org/D22071
This commit is contained in:
Eric Joyner 2019-10-23 23:20:49 +00:00
parent f1664f3258
commit 1558015e3e
1 changed files with 24 additions and 8 deletions

32
sys/net/iflib.c

@ -703,6 +703,7 @@ static int iflib_altq_if_transmit(if_t ifp, struct mbuf *m);
#endif
static int iflib_register(if_ctx_t);
static void iflib_deregister(if_ctx_t);
static void iflib_unregister_vlan_handlers(if_ctx_t ctx);
static void iflib_init_locked(if_ctx_t ctx);
static void iflib_add_device_sysctl_pre(if_ctx_t ctx);
static void iflib_add_device_sysctl_post(if_ctx_t ctx);
@ -5007,6 +5008,9 @@ iflib_pseudo_deregister(if_ctx_t ctx)
struct taskqgroup *tqg;
iflib_fl_t fl;
/* Unregister VLAN event handlers early */
iflib_unregister_vlan_handlers(ctx);
ether_ifdetach(ifp);
/* XXX drain any dependent tasks */
tqg = qgroup_if_io_tqg;
@ -5080,12 +5084,16 @@ iflib_device_deregister(if_ctx_t ctx)
ctx->ifc_flags |= IFC_IN_DETACH;
STATE_UNLOCK(ctx);
/* Unregister VLAN handlers before calling iflib_stop() */
iflib_unregister_vlan_handlers(ctx);
iflib_netmap_detach(ifp);
ether_ifdetach(ifp);
CTX_LOCK(ctx);
iflib_stop(ctx);
CTX_UNLOCK(ctx);
iflib_netmap_detach(ifp);
ether_ifdetach(ifp);
iflib_rem_pfil(ctx);
if (ctx->ifc_led_dev != NULL)
led_destroy(ctx->ifc_led_dev);
@ -5375,13 +5383,8 @@ iflib_register(if_ctx_t ctx)
}
static void
iflib_deregister(if_ctx_t ctx)
iflib_unregister_vlan_handlers(if_ctx_t ctx)
{
if_t ifp = ctx->ifc_ifp;
/* Remove all media */
ifmedia_removeall(&ctx->ifc_media);
/* Unregister VLAN events */
if (ctx->ifc_vlan_attach_event != NULL) {
EVENTHANDLER_DEREGISTER(vlan_config, ctx->ifc_vlan_attach_event);
@ -5392,6 +5395,19 @@ iflib_deregister(if_ctx_t ctx)
ctx->ifc_vlan_detach_event = NULL;
}
}
static void
iflib_deregister(if_ctx_t ctx)
{
if_t ifp = ctx->ifc_ifp;
/* Remove all media */
ifmedia_removeall(&ctx->ifc_media);
/* Ensure that VLAN event handlers are unregistered */
iflib_unregister_vlan_handlers(ctx);
/* Release kobject reference */
kobj_delete((kobj_t) ctx, NULL);