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Fix a race in tcpdns close with uv_close on timer

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stop timers before closing

netmgr: tcpdns_close needs to be asynchronous, it manipulates sock->timer
This commit is contained in:
Witold Kręcicki
2019-12-06 22:25:52 +01:00
parent 23ab349bbd
commit 3e66b7ba1c
4 changed files with 60 additions and 26 deletions
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39
lib/isc/netmgr/netmgr.c
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@@ -550,6 +550,9 @@ process_queue(isc__networker_t *worker, isc_queue_t *queue) {
case netievent_tcpclose:
isc__nm_async_tcpclose(worker, ievent);
break;
case netievent_tcpdnsclose:
isc__nm_async_tcpdnsclose(worker, ievent);
break;
case netievent_closecb:
isc__nm_async_closecb(worker, ievent);
break;
@@ -675,8 +678,9 @@ nmsocket_cleanup(isc_nmsocket_t *sock, bool dofree) {
sock->pquota = NULL;
if (sock->timer_initialized) {
uv_close((uv_handle_t *)&sock->timer, NULL);
sock->timer_initialized = false;
uv_timer_stop(&sock->timer);
uv_close((uv_handle_t *)&sock->timer, NULL);
}
isc_astack_destroy(sock->inactivehandles);
@@ -1022,6 +1026,7 @@ isc_nmhandle_unref(isc_nmhandle_t *handle) {
isc_nmsocket_t *sock = NULL;
size_t handlenum;
bool reuse = false;
bool do_close = true;
int refs;
REQUIRE(VALID_NMHANDLE(handle));
@@ -1039,28 +1044,28 @@ isc_nmhandle_unref(isc_nmhandle_t *handle) {
handle->doreset(handle->opaque);
}
/*
* The handle is closed. If the socket has a callback configured
* for that (e.g., to perform cleanup after request processing),
* call it now.
* call it now, or schedule it to run asynchronously.
*/
bool do_close = true;
if (sock->closehandle_cb != NULL) {
if (sock->tid == isc_nm_tid()) {
sock->closehandle_cb(sock);
} else {
isc__netievent_closecb_t * event =
isc__netievent_closecb_t *event =
isc__nm_get_ievent(sock->mgr,
netievent_closecb);
isc_nmsocket_attach(sock, &event->sock);
isc__nm_enqueue_ievent(&sock->mgr->workers[sock->tid],
(isc__netievent_t *) event);
/*
* If we do this asynchronously then the async event
* will clean the socket, so clean up the handle from
* socket and exit.
* If we're doing this asynchronously, then the
* async event will take care of closing the
* socket, so we can clean up the handle
* from the socket, but skip calling
* nmsocket_maybe_destory()
*/
do_close = false;
}
@@ -1068,9 +1073,8 @@ isc_nmhandle_unref(isc_nmhandle_t *handle) {
/*
* We do all of this under lock to avoid races with socket
* destruction.
* We have to do this now otherwise we might race - at this point
* the socket is either unused or attached to event->sock.
* destruction. We have to do this now, because at this point the
* socket is either unused or still attached to event->sock.
*/
LOCK(&sock->lock);
@@ -1092,15 +1096,8 @@ isc_nmhandle_unref(isc_nmhandle_t *handle) {
}
UNLOCK(&sock->lock);
/* Close callback will clean everything up */
if (!do_close) {
return;
}
if (atomic_load(&sock->ah) == 0 &&
!atomic_load(&sock->active) &&
!atomic_load(&sock->destroying))
if (do_close && atomic_load(&sock->ah) == 0 &&
!atomic_load(&sock->active) && !atomic_load(&sock->destroying))
{
nmsocket_maybe_destroy(sock);
}