From nobody Wed Feb 11 02:08:38 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1763782205160561.3013292966233; Fri, 21 Nov 2025 19:30:05 -0800 (PST) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1vMdhf-0003wa-5p; Fri, 21 Nov 2025 21:50:24 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1vMdhZ-0003sm-0u; Fri, 21 Nov 2025 21:50:17 -0500 Received: from isrv.corpit.ru ([212.248.84.144]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1vMdgz-0005qZ-Q6; Fri, 21 Nov 2025 21:50:12 -0500 Received: from tsrv.corpit.ru (tsrv.tls.msk.ru [192.168.177.2]) by isrv.corpit.ru (Postfix) with ESMTP id 0262716C708; Fri, 21 Nov 2025 16:51:58 +0300 (MSK) Received: from think4mjt.tls.msk.ru (mjtthink.wg.tls.msk.ru [192.168.177.146]) by tsrv.corpit.ru (Postfix) with ESMTP id 5B2793219A5; Fri, 21 Nov 2025 16:52:06 +0300 (MSK) From: Michael Tokarev To: qemu-devel@nongnu.org Cc: qemu-stable@nongnu.org, Eric Blake , =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= , Michael Tokarev Subject: [Stable-10.1.3 48/76] qio: Remember context of qio_net_listener_set_client_func_full Date: Fri, 21 Nov 2025 16:51:26 +0300 Message-ID: <20251121135201.1114964-48-mjt@tls.msk.ru> X-Mailer: git-send-email 2.47.3 In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=212.248.84.144; envelope-from=mjt@tls.msk.ru; helo=isrv.corpit.ru X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, T_SPF_HELO_TEMPERROR=0.01, T_SPF_TEMPERROR=0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZM-MESSAGEID: 1763782207579018900 From: Eric Blake io/net-listener.c has two modes of use: asynchronous (the user calls qio_net_listener_set_client_func to wake up the callback via the global GMainContext, or qio_net_listener_set_client_func_full to wake up the callback via the caller's own alternative GMainContext), and synchronous (the user calls qio_net_listener_wait_client which creates its own GMainContext and waits for the first client connection before returning, with no need for a user's callback). But commit 938c8b79 has a latent logic flaw: when qio_net_listener_wait_client finishes on its temporary context, it reverts all of the siocs back to the global GMainContext rather than the potentially non-NULL context they might have been originally registered with. Similarly, if the user creates a net-listener, adds initial addresses, registers an async callback with a non-default context (which ties to all siocs for the initial addresses), then adds more addresses with qio_net_listener_add, the siocs for later addresses are blindly placed in the global context, rather than sharing the context of the earlier ones. In practice, I don't think this has caused issues. As pointed out by the original commit, all async callers prior to that commit were already okay with the NULL default context; and the typical usage pattern is to first add ALL the addresses the listener will pay attention to before ever setting the async callback. Likewise, if a file uses only qio_net_listener_set_client_func instead of qio_net_listener_set_client_func_full, then it is never using a custom context, so later assignments of async callbacks will still be to the same global context as earlier ones. Meanwhile, any callers that want to do the sync operation to grab the first client are unlikely to register an async callback; altogether bypassing the question of whether later assignments of a GSource are being tied to a different context over time. I do note that chardev/char-socket.c is the only file that calls both qio_net_listener_wait_client (sync for a single client in tcp_chr_accept_server_sync), and qio_net_listener_set_client_func_full (several places, all with chr->gcontext, but sometimes with a NULL callback function during teardown). But as far as I can tell, the two uses are mutually exclusive, based on the is_waitconnect parameter to qmp_chardev_open_socket_server. That said, it is more robust to remember when an async callback function is tied to a non-default context, and have both the sync wait and any late address additions honor that same context. That way, the code will be robust even if a later user performs a sync wait for a specific client in the middle of servicing a longer-lived QIONetListener that has an async callback for all other clients. CC: qemu-stable@nongnu.org Fixes: 938c8b79 ("qio: store gsources for net listeners", v2.12.0) Signed-off-by: Eric Blake Reviewed-by: Daniel P. Berrang=C3=A9 Message-ID: <20251113011625.878876-19-eblake@redhat.com> (cherry picked from commit b5676493a08b4ff80680aae7a1b1bfef8797c6e7) Signed-off-by: Michael Tokarev diff --git a/include/io/net-listener.h b/include/io/net-listener.h index ab9f291ed6..42fbfab546 100644 --- a/include/io/net-listener.h +++ b/include/io/net-listener.h @@ -50,6 +50,7 @@ struct QIONetListener { QIOChannelSocket **sioc; GSource **io_source; size_t nsioc; + GMainContext *context; =20 bool connected; =20 diff --git a/io/net-listener.c b/io/net-listener.c index d71b65270e..0f16b78fbb 100644 --- a/io/net-listener.c +++ b/io/net-listener.c @@ -51,7 +51,8 @@ static gboolean qio_net_listener_channel_func(QIOChannel = *ioc, return TRUE; } =20 - trace_qio_net_listener_callback(listener, listener->io_func); + trace_qio_net_listener_callback(listener, listener->io_func, + listener->context); if (listener->io_func) { listener->io_func(listener, sioc, listener->io_data); } @@ -125,13 +126,14 @@ void qio_net_listener_add(QIONetListener *listener, object_ref(OBJECT(sioc)); listener->connected =3D true; =20 - trace_qio_net_listener_watch(listener, listener->io_func, "add"); + trace_qio_net_listener_watch(listener, listener->io_func, + listener->context, "add"); if (listener->io_func !=3D NULL) { object_ref(OBJECT(listener)); listener->io_source[listener->nsioc] =3D qio_channel_add_watch_sou= rce( QIO_CHANNEL(listener->sioc[listener->nsioc]), G_IO_IN, qio_net_listener_channel_func, - listener, (GDestroyNotify)object_unref, NULL); + listener, (GDestroyNotify)object_unref, listener->context); } =20 listener->nsioc++; @@ -147,7 +149,8 @@ void qio_net_listener_set_client_func_full(QIONetListen= er *listener, size_t i; =20 trace_qio_net_listener_unwatch(listener, listener->io_func, - "set_client_func"); + listener->context, "set_client_func"); + for (i =3D 0; i < listener->nsioc; i++) { if (listener->io_source[i]) { g_source_destroy(listener->io_source[i]); @@ -162,9 +165,10 @@ void qio_net_listener_set_client_func_full(QIONetListe= ner *listener, listener->io_func =3D func; listener->io_data =3D data; listener->io_notify =3D notify; + listener->context =3D context; =20 trace_qio_net_listener_watch(listener, listener->io_func, - "set_client_func"); + listener->context, "set_client_func"); if (listener->io_func !=3D NULL) { for (i =3D 0; i < listener->nsioc; i++) { object_ref(OBJECT(listener)); @@ -225,7 +229,8 @@ QIOChannelSocket *qio_net_listener_wait_client(QIONetLi= stener *listener) }; size_t i; =20 - trace_qio_net_listener_unwatch(listener, listener->io_func, "wait_clie= nt"); + trace_qio_net_listener_unwatch(listener, listener->io_func, + listener->context, "wait_client"); for (i =3D 0; i < listener->nsioc; i++) { if (listener->io_source[i]) { g_source_destroy(listener->io_source[i]); @@ -255,14 +260,15 @@ QIOChannelSocket *qio_net_listener_wait_client(QIONet= Listener *listener) g_main_loop_unref(loop); g_main_context_unref(ctxt); =20 - trace_qio_net_listener_watch(listener, listener->io_func, "wait_client= "); + trace_qio_net_listener_watch(listener, listener->io_func, + listener->context, "wait_client"); if (listener->io_func !=3D NULL) { for (i =3D 0; i < listener->nsioc; i++) { object_ref(OBJECT(listener)); listener->io_source[i] =3D qio_channel_add_watch_source( QIO_CHANNEL(listener->sioc[i]), G_IO_IN, qio_net_listener_channel_func, - listener, (GDestroyNotify)object_unref, NULL); + listener, (GDestroyNotify)object_unref, listener->context); } } =20 @@ -277,7 +283,8 @@ void qio_net_listener_disconnect(QIONetListener *listen= er) return; } =20 - trace_qio_net_listener_unwatch(listener, listener->io_func, "disconnec= t"); + trace_qio_net_listener_unwatch(listener, listener->io_func, + listener->context, "disconnect"); for (i =3D 0; i < listener->nsioc; i++) { if (listener->io_source[i]) { g_source_destroy(listener->io_source[i]); diff --git a/io/trace-events b/io/trace-events index 10976eca5f..0cb77d579b 100644 --- a/io/trace-events +++ b/io/trace-events @@ -74,6 +74,6 @@ qio_channel_command_abort(void *ioc, int pid) "Command ab= ort ioc=3D%p pid=3D%d" qio_channel_command_wait(void *ioc, int pid, int ret, int status) "Command= abort ioc=3D%p pid=3D%d ret=3D%d status=3D%d" =20 # net-listener.c -qio_net_listener_watch(void *listener, void *func, const char *extra) "Net= listener=3D%p watch enabled func=3D%p by %s" -qio_net_listener_unwatch(void *listener, void *func, const char *extra) "N= et listener=3D%p watch disabled func=3D%p by %s" -qio_net_listener_callback(void *listener, void *func) "Net listener=3D%p c= allback forwarding to func=3D%p" +qio_net_listener_watch(void *listener, void *func, void *ctx, const char *= extra) "Net listener=3D%p watch enabled func=3D%p ctx=3D%p by %s" +qio_net_listener_unwatch(void *listener, void *func, void *ctx, const char= *extra) "Net listener=3D%p watch disabled func=3D%p ctx=3D%p by %s" +qio_net_listener_callback(void *listener, void *func, void *ctx) "Net list= ener=3D%p callback forwarding to func=3D%p ctx=3D%p" --=20 2.47.3