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Code Issues Releases Wiki Activity

Fix a race between isc__nm_async_shutdown() and new sends/reads

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There was a data race where a new event could be scheduled after
isc__nm_async_shutdown() had cleaned up all the dangling UDP/TCP
sockets from the loop.
This commit is contained in:
Ondřej Surý
2020-10-27 20:00:08 +01:00
committed by Ondřej Surý
parent 5fcd52209a
commit 6cfadf9db0
4 changed files with 247 additions and 91 deletions
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159
lib/isc/netmgr/tcp.c
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@@ -77,6 +77,42 @@ accept_connection(isc_nmsocket_t *ssock, isc_quota_t *quota);
static void
quota_accept_cb(isc_quota_t *quota, void *sock0);
static void
failed_accept_cb(isc_nmsocket_t *sock, isc_result_t eresult);
static void
failed_accept_cb(isc_nmsocket_t *sock, isc_result_t eresult) {
/*
* Detach the quota early to make room for other connections;
* otherwise it'd be detached later asynchronously, and clog
* the quota unnecessarily.
*/
if (sock->quota != NULL) {
isc_quota_detach(&sock->quota);
}
if (!sock->accepting) {
return;
}
sock->accepting = false;
switch (eresult) {
case ISC_R_NOTCONNECTED:
/* IGNORE: The client disconnected before we could accept */
break;
default:
isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL,
ISC_LOGMODULE_NETMGR, ISC_LOG_ERROR,
"Accepting TCP connection failed: %s",
isc_result_totext(eresult));
}
/*
* Detach the socket properly to make sure uv_close() is called.
*/
isc__nmsocket_detach(&sock);
}
static void
failed_connect_cb(isc_nmsocket_t *sock, isc_result_t eresult) {
isc__nm_uvreq_t *req;
@@ -87,10 +123,11 @@ failed_connect_cb(isc_nmsocket_t *sock, isc_result_t eresult) {
sock->timer_running = false;
}
if (!sock->connecting) {
if (!atomic_load(&sock->connecting)) {
return;
}
sock->connecting = false;
atomic_store(&sock->connecting, false);
req = uv_handle_get_data((uv_handle_t *)&sock->timer);
@@ -131,7 +168,7 @@ tcp_connect_direct(isc_nmsocket_t *sock, isc__nm_uvreq_t *req) {
sock->timer_initialized = true;
}
sock->connecting = true;
atomic_store(&sock->connecting, true);
r = uv_tcp_init(&worker->loop, &sock->uv_handle.tcp);
if (r != 0) {
@@ -225,10 +262,11 @@ tcp_connect_cb(uv_connect_t *uvreq, int status) {
sock->timer_running = false;
}
if (!sock->connecting) {
if (!atomic_load(&sock->connecting)) {
return;
}
sock->connecting = false;
atomic_store(&sock->connecting, false);
REQUIRE(VALID_UVREQ(req));
@@ -514,6 +552,23 @@ isc__nm_async_tcpchildaccept(isc__networker_t *worker, isc__netievent_t *ev0) {
REQUIRE(isc__nm_in_netthread());
REQUIRE(sock->tid == isc_nm_tid());
if (!sock->accepting) {
return;
}
/* Socket was closed midflight by isc__nm_tcp_shutdown() */
if (!isc__nmsocket_active(sock)) {
failed_accept_cb(sock, ISC_R_CANCELED);
return;
}
INSIST(sock->server != NULL);
if (!isc__nmsocket_active(sock->server)) {
failed_accept_cb(sock, ISC_R_CANCELED);
return;
}
sock->quota = ievent->quota;
ievent->quota = NULL;
@@ -553,6 +608,7 @@ isc__nm_async_tcpchildaccept(isc__networker_t *worker, isc__netievent_t *ev0) {
if (result != ISC_R_SUCCESS) {
goto error;
}
sock->accepting = false;
handle = isc__nmhandle_get(sock, NULL, &local);
@@ -576,30 +632,7 @@ isc__nm_async_tcpchildaccept(isc__networker_t *worker, isc__netievent_t *ev0) {
return;
error:
/*
* Detach the quota early to make room for other connections;
* otherwise it'd be detached later asynchronously, and clog
* the quota unnecessarily.
*/
if (sock->quota != NULL) {
isc_quota_detach(&sock->quota);
}
switch (result) {
case ISC_R_NOTCONNECTED:
/* IGNORE: The client disconnected before we could accept */
break;
default:
isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL,
ISC_LOGMODULE_NETMGR, ISC_LOG_ERROR,
"Accepting TCP connection failed: %s",
isc_result_totext(result));
}
/*
* Detach the socket properly to make sure uv_close() is called.
*/
isc__nmsocket_detach(&sock);
failed_accept_cb(sock, result);
}
void
@@ -666,8 +699,6 @@ failed_read_cb(isc_nmsocket_t *sock, isc_result_t result) {
REQUIRE(VALID_NMSOCK(sock));
REQUIRE(sock->statichandle != NULL);
uv_read_stop(&sock->uv_handle.stream);
if (sock->timer_initialized) {
uv_timer_stop(&sock->timer);
sock->timer_running = false;
@@ -677,6 +708,8 @@ failed_read_cb(isc_nmsocket_t *sock, isc_result_t result) {
isc_quota_detach(&sock->quota);
}
uv_read_stop(&sock->uv_handle.stream);
cb = sock->recv_cb;
cbarg = sock->recv_cbarg;
isc__nmsocket_clearcb(sock);
@@ -699,6 +732,7 @@ readtimeout_cb(uv_timer_t *handle) {
*/
if (atomic_load(&sock->processing)) {
uv_timer_start(handle, readtimeout_cb, sock->read_timeout, 0);
sock->timer_running = true;
return;
}
@@ -722,6 +756,18 @@ isc__nm_tcp_read(isc_nmhandle_t *handle, isc_nm_recv_cb_t cb, void *cbarg) {
return;
}
if (sock->server != NULL && !isc__nmsocket_active(sock->server)) {
isc__nm_incstats(sock->mgr, sock->statsindex[STATID_SENDFAIL]);
cb(handle, ISC_R_CANCELED, NULL, cbarg);
return;
}
if (atomic_load(&sock->mgr->closing)) {
isc__nm_incstats(sock->mgr, sock->statsindex[STATID_SENDFAIL]);
cb(handle, ISC_R_CANCELED, NULL, cbarg);
return;
}
REQUIRE(sock->tid == isc_nm_tid());
sock->recv_cb = cb;
@@ -774,6 +820,21 @@ isc__nm_async_tcp_startread(isc__networker_t *worker, isc__netievent_t *ev0) {
REQUIRE(worker->id == isc_nm_tid());
if (!isc__nmsocket_active(sock)) {
failed_read_cb(sock, ISC_R_CANCELED);
return;
}
if (sock->server != NULL && !isc__nmsocket_active(sock->server)) {
failed_read_cb(sock, ISC_R_CANCELED);
return;
}
if (atomic_load(&sock->mgr->closing)) {
failed_read_cb(sock, ISC_R_CANCELED);
return;
}
r = uv_read_start(&sock->uv_handle.stream, tcp_alloc_cb, read_cb);
if (r != 0) {
isc__nm_incstats(sock->mgr, sock->statsindex[STATID_RECVFAIL]);
@@ -894,6 +955,7 @@ read_cb(uv_stream_t *stream, ssize_t nread, const uv_buf_t *buf) {
/* The timer will be updated */
uv_timer_start(&sock->timer, readtimeout_cb,
sock->read_timeout, 0);
sock->timer_running = true;
}
} else {
/*
@@ -1053,6 +1115,7 @@ accept_connection(isc_nmsocket_t *ssock, isc_quota_t *quota) {
isc__nmsocket_attach(ssock, &csock->server);
csock->accept_cb = ssock->accept_cb;
csock->accept_cbarg = ssock->accept_cbarg;
csock->accepting = true;
event->sock = csock;
event->quota = quota;
@@ -1086,6 +1149,18 @@ isc__nm_tcp_send(isc_nmhandle_t *handle, isc_region_t *region, isc_nm_cb_t cb,
return;
}
if (sock->server != NULL && !isc__nmsocket_active(sock->server)) {
isc__nm_incstats(sock->mgr, sock->statsindex[STATID_SENDFAIL]);
cb(handle, ISC_R_CANCELED, cbarg);
return;
}
if (atomic_load(&sock->mgr->closing)) {
isc__nm_incstats(sock->mgr, sock->statsindex[STATID_SENDFAIL]);
cb(handle, ISC_R_CANCELED, cbarg);
return;
}
uvreq = isc__nm_uvreq_get(sock->mgr, sock);
uvreq->uvbuf.base = (char *)region->base;
uvreq->uvbuf.len = region->length;
@@ -1172,6 +1247,12 @@ tcp_send_direct(isc_nmsocket_t *sock, isc__nm_uvreq_t *req) {
if (!isc__nmsocket_active(sock)) {
return (ISC_R_CANCELED);
}
if (sock->server != NULL && !isc__nmsocket_active(sock->server)) {
return (ISC_R_CANCELED);
}
if (atomic_load(&sock->mgr->closing)) {
return (ISC_R_CANCELED);
}
r = uv_write(&req->uv_req.write, &sock->uv_handle.stream, &req->uvbuf,
1, tcp_send_cb);
@@ -1269,6 +1350,15 @@ isc__nm_tcp_shutdown(isc_nmsocket_t *sock) {
REQUIRE(VALID_NMSOCK(sock));
REQUIRE(sock->tid == isc_nm_tid());
if (sock->type != isc_nm_tcpsocket) {
return;
}
if (atomic_load(&sock->connecting)) {
failed_connect_cb(sock, ISC_R_CANCELED);
return;
}
/*
* If the socket is active, mark it inactive and
* continue. If it isn't active, stop now.
@@ -1277,12 +1367,12 @@ isc__nm_tcp_shutdown(isc_nmsocket_t *sock) {
return;
}
if (sock->connecting) {
failed_connect_cb(sock, ISC_R_CANCELED);
if (sock->accepting) {
failed_accept_cb(sock, ISC_R_CANCELED);
return;
}
if (sock->type == isc_nm_tcpsocket && sock->statichandle != NULL) {
if (sock->statichandle != NULL) {
failed_read_cb(sock, ISC_R_CANCELED);
}
}
@@ -1296,6 +1386,7 @@ isc__nm_tcp_cancelread(isc_nmhandle_t *handle) {
sock = handle->sock;
REQUIRE(VALID_NMSOCK(sock));
REQUIRE(sock->type == isc_nm_tcpsocket);
ievent = isc__nm_get_ievent(sock->mgr, netievent_tcpcancel);