From nobody Sun Nov 9 14:46:29 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.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; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 209.51.188.17 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 (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1551286269535719.5089297278201; Wed, 27 Feb 2019 08:51:09 -0800 (PST) Received: from localhost ([127.0.0.1]:47249 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gz2Q9-00063F-2X for importer@patchew.org; Wed, 27 Feb 2019 11:51:01 -0500 Received: from eggs.gnu.org ([209.51.188.92]:43521) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gz2OL-00059k-FE for qemu-devel@nongnu.org; Wed, 27 Feb 2019 11:49:10 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gz2OJ-0002cO-Ts for qemu-devel@nongnu.org; Wed, 27 Feb 2019 11:49:09 -0500 Received: from mx1.redhat.com ([209.132.183.28]:60282) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gz2OJ-0002bO-IQ for qemu-devel@nongnu.org; Wed, 27 Feb 2019 11:49:07 -0500 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 6257840250; Wed, 27 Feb 2019 16:49:06 +0000 (UTC) Received: from dgilbert-t580.localhost (unknown [10.36.118.3]) by smtp.corp.redhat.com (Postfix) with ESMTP id 81220600C2; Wed, 27 Feb 2019 16:49:02 +0000 (UTC) From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org, quintela@redhat.com, peterx@redhat.com, alex.bennee@linaro.org Date: Wed, 27 Feb 2019 16:49:00 +0000 Message-Id: <20190227164900.16378-1-dgilbert@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Wed, 27 Feb 2019 16:49:06 +0000 (UTC) Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH] migration: Cleanup during exit 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: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" Content-Type: text/plain; charset="utf-8" From: "Dr. David Alan Gilbert" Currently we cleanup the migration object as we exit main after the main_loop finishes; however if there's a migration running things get messy and we can end up with the migration thread still trying to access freed structures. We now take a ref to the object around the migration thread itself, so the act of dropping the ref during exit doesn't cause us to lose the state until the thread quits. Cancelling the migration during migration also tries to get the thread to quit. We do this a bit earlier; so hopefully migration gets out of the way before all the devices etc are freed. Signed-off-by: Dr. David Alan Gilbert Tested-by: Alex Benn=C3=A9e Reviewed-by: Alex Benn=C3=A9e Reviewed-by: Juan Quintela --- include/migration/misc.h | 2 +- migration/migration.c | 10 +++++++++- vl.c | 7 ++++++- 3 files changed, 16 insertions(+), 3 deletions(-) diff --git a/include/migration/misc.h b/include/migration/misc.h index 0471e04d1f..6f9df74436 100644 --- a/include/migration/misc.h +++ b/include/migration/misc.h @@ -36,7 +36,7 @@ void dump_vmstate_json_to_file(FILE *out_fp); =20 /* migration/migration.c */ void migration_object_init(void); -void migration_object_finalize(void); +void migration_shutdown(void); void qemu_start_incoming_migration(const char *uri, Error **errp); bool migration_is_idle(void); void add_migration_state_change_notifier(Notifier *notify); diff --git a/migration/migration.c b/migration/migration.c index e44f77af02..d45561f9b8 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -126,6 +126,7 @@ static bool migration_object_check(MigrationState *ms, = Error **errp); static int migration_maybe_pause(MigrationState *s, int *current_active_state, int new_state); +static void migrate_fd_cancel(MigrationState *s); =20 void migration_object_init(void) { @@ -167,8 +168,13 @@ void migration_object_init(void) } } =20 -void migration_object_finalize(void) +void migration_shutdown(void) { + /* + * Cancel the current migration - that will (eventually) + * stop the migration using this structure + */ + migrate_fd_cancel(current_migration); object_unref(OBJECT(current_migration)); } =20 @@ -3134,6 +3140,7 @@ static void *migration_thread(void *opaque) =20 rcu_register_thread(); =20 + object_ref(OBJECT(s)); s->iteration_start_time =3D qemu_clock_get_ms(QEMU_CLOCK_REALTIME); =20 qemu_savevm_state_header(s->to_dst_file); @@ -3230,6 +3237,7 @@ static void *migration_thread(void *opaque) =20 trace_migration_thread_after_loop(); migration_iteration_finish(s); + object_unref(OBJECT(s)); rcu_unregister_thread(); return NULL; } diff --git a/vl.c b/vl.c index 2f340686a7..e7f460a114 100644 --- a/vl.c +++ b/vl.c @@ -4579,6 +4579,12 @@ int main(int argc, char **argv, char **envp) =20 gdbserver_cleanup(); =20 + /* + * cleaning up the migration object cancels any existing migration + * try to do this early so that it also stops using devices. + */ + migration_shutdown(); + /* No more vcpu or device emulation activity beyond this point */ vm_shutdown(); =20 @@ -4594,7 +4600,6 @@ int main(int argc, char **argv, char **envp) monitor_cleanup(); qemu_chr_cleanup(); user_creatable_cleanup(); - migration_object_finalize(); /* TODO: unref root container, check all devices are ok */ =20 return 0; --=20 2.20.1