From nobody Thu Nov 6 22:56:53 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (208.118.235.17 [208.118.235.17]) by mx.zohomail.com with SMTPS id 1543929914926812.0094759877005; Tue, 4 Dec 2018 05:25:14 -0800 (PST) Received: from localhost ([::1]:56718 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gUAhG-0004dr-Ow for importer@patchew.org; Tue, 04 Dec 2018 08:25:06 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54617) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gUAbS-0005Z4-Q5 for qemu-devel@nongnu.org; Tue, 04 Dec 2018 08:19:08 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gUAbP-0002df-Mb for qemu-devel@nongnu.org; Tue, 04 Dec 2018 08:19:06 -0500 Received: from mx1.redhat.com ([209.132.183.28]:57256) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gUAbP-0002cd-Gu for qemu-devel@nongnu.org; Tue, 04 Dec 2018 08:19:03 -0500 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id D91C25F for ; Tue, 4 Dec 2018 13:19:02 +0000 (UTC) Received: from localhost (ovpn-112-31.ams2.redhat.com [10.36.112.31]) by smtp.corp.redhat.com (Postfix) with ESMTP id 533AD611D2; Tue, 4 Dec 2018 13:18:56 +0000 (UTC) From: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= To: qemu-devel@nongnu.org Date: Tue, 4 Dec 2018 17:18:01 +0400 Message-Id: <20181204131802.16885-6-marcandre.lureau@redhat.com> In-Reply-To: <20181204131802.16885-1-marcandre.lureau@redhat.com> References: <20181204131802.16885-1-marcandre.lureau@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Tue, 04 Dec 2018 13:19:02 +0000 (UTC) Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v3 5/6] monitor: prevent inserting new monitors after cleanup X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Paolo Bonzini , "Dr. David Alan Gilbert" , Markus Armbruster , peterx@redhat.com, =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" Content-Type: text/plain; charset="utf-8" monitor_cleanup() is one of the last things main() calls before it returns. In the following patch, monitor_cleanup() will release the monitor_lock during flushing. There may be pending commands to insert new monitors, which would modify the mon_list during iteration, and the clean-up could thus miss those new insertions. Add a monitor_destroyed global to check if monitor_cleanup() has been already called. In this case, don't insert the new monitor in the list, but free it instead. Signed-off-by: Marc-Andr=C3=A9 Lureau Reviewed-by: Markus Armbruster --- monitor.c | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-) diff --git a/monitor.c b/monitor.c index 25cf4223e8..f0256bdec5 100644 --- a/monitor.c +++ b/monitor.c @@ -263,10 +263,11 @@ typedef struct QMPRequest QMPRequest; /* QMP checker flags */ #define QMP_ACCEPT_UNKNOWNS 1 =20 -/* Protects mon_list, monitor_qapi_event_state. */ +/* Protects mon_list, monitor_qapi_event_state, monitor_destroyed. */ static QemuMutex monitor_lock; static GHashTable *monitor_qapi_event_state; static QTAILQ_HEAD(mon_list, Monitor) mon_list; +static bool monitor_destroyed; =20 /* Protects mon_fdsets */ static QemuMutex mon_fdsets_lock; @@ -4538,8 +4539,21 @@ void error_vprintf_unless_qmp(const char *fmt, va_li= st ap) static void monitor_list_append(Monitor *mon) { qemu_mutex_lock(&monitor_lock); - QTAILQ_INSERT_HEAD(&mon_list, mon, entry); + /* + * This prevents inserting new monitors during monitor_cleanup(). + * A cleaner solution would involve the main thread telling other + * threads to terminate, waiting for their termination. + */ + if (!monitor_destroyed) { + QTAILQ_INSERT_HEAD(&mon_list, mon, entry); + mon =3D NULL; + } qemu_mutex_unlock(&monitor_lock); + + if (mon) { + monitor_data_destroy(mon); + g_free(mon); + } } =20 static void monitor_qmp_setup_handlers_bh(void *opaque) @@ -4635,6 +4649,7 @@ void monitor_cleanup(void) =20 /* Flush output buffers and destroy monitors */ qemu_mutex_lock(&monitor_lock); + monitor_destroyed =3D true; QTAILQ_FOREACH_SAFE(mon, &mon_list, entry, next) { QTAILQ_REMOVE(&mon_list, mon, entry); monitor_flush(mon); --=20 2.20.0.rc1