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Deactivate the handle before sending the async close callback.

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We could have a race between handle closing and processing async
callback. Deactivate the handle before issuing the callback - we
have the socket referenced anyway so it's not a problem.
This commit is contained in:
Witold Kręcicki 2020-03-26 14:25:06 +01:00
parent 2df610a882
commit 01c4c3301e
3 changed files with 19 additions and 20 deletions
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5
CHANGES
View File

@ -1,3 +1,8 @@
5370. [bug] Deactivation of a netmgr handle associated with a
socket could be skipped in some circumstances.
Fixed by deactivating the netmgr handle before
scheduling the asynchronous close routine. [GL #1700]
5369. [func] Add the ability to specify whether or not to wait
for nameserver domain names to be looked up, with
a new RPZ modifying directive 'nsdname-wait-recurse'.

3
lib/isc/netmgr/netmgr-int.h
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@ -216,6 +216,7 @@ typedef isc__netievent__socket_t isc__netievent_tcpclose_t;
typedef isc__netievent__socket_t isc__netievent_tcpdnsclose_t;
typedef isc__netievent__socket_t isc__netievent_startread_t;
typedef isc__netievent__socket_t isc__netievent_pauseread_t;
typedef isc__netievent__socket_t isc__netievent_closecb_t;
typedef struct isc__netievent__socket_req {
isc__netievent_type type;
@ -241,8 +242,6 @@ typedef struct isc__netievent__socket_handle {
isc_nmhandle_t *handle;
} isc__netievent__socket_handle_t;
typedef isc__netievent__socket_handle_t isc__netievent_closecb_t;
typedef struct isc__netievent_udpsend {
isc__netievent_type type;
isc_nmsocket_t *sock;

31
lib/isc/netmgr/netmgr.c
View File

@ -1164,7 +1164,15 @@ isc_nmhandle_unref(isc_nmhandle_t *handle) {
}
/*
* The handle is closed. If the socket has a callback configured
* Temporarily reference the socket to ensure that it can't
* be deleted by another thread while we're deactivating the
* handle.
*/
isc_nmsocket_attach(sock, &tmp);
nmhandle_deactivate(sock, handle);
/*
* The handle is gone now. If the socket has a callback configured
* for that (e.g., to perform cleanup after request processing),
* call it now, or schedule it to run asynchronously.
*/
@ -1174,27 +1182,16 @@ isc_nmhandle_unref(isc_nmhandle_t *handle) {
} else {
isc__netievent_closecb_t *event = isc__nm_get_ievent(
sock->mgr, netievent_closecb);
/*
* The socket will be finally detached by the closecb
* event handler.
*/
isc_nmsocket_attach(sock, &event->sock);
event->handle = handle;
isc__nm_enqueue_ievent(&sock->mgr->workers[sock->tid],
(isc__netievent_t *)event);
/*
* If we're doing this asynchronously, then the
* async event will take care of cleaning up the
* handle and closing the socket.
*/
return;
}
}
/*
* Temporarily reference the socket to ensure that it can't
* be deleted by another thread while we're deactivating the
* handle.
*/
isc_nmsocket_attach(sock, &tmp);
nmhandle_deactivate(sock, handle);
isc_nmsocket_detach(&tmp);
}
@ -1387,8 +1384,6 @@ isc__nm_async_closecb(isc__networker_t *worker, isc__netievent_t *ev0) {
UNUSED(worker);
nmhandle_deactivate(ievent->sock, ievent->handle);
ievent->sock->closehandle_cb(ievent->sock);
isc_nmsocket_detach(&ievent->sock);
}