From nobody Tue Feb 10 00:22:49 2026 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 ARC-Seal: i=1; a=rsa-sha256; t=1564052296; cv=none; d=zoho.com; s=zohoarc; b=QiZAfgzcvde+8PJkGVBjayunwVC++s6AZxIiSNKqomvwk/vsA4mxJ+w3k+f13l2WqOPBCUzqxUUKimNpRPxoHtbA+S02zmpg5n238znujuiej2PYWjctyjgmWwmDLSy+3dv+k45ASS656tcRkbveHVT1HI5e24DL32j8XM0rjaQ= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zoho.com; s=zohoarc; t=1564052296; h=Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To:ARC-Authentication-Results; bh=1q2UtyxXiq9nFYmP8cTR7xXRyGrXP627hnv3jFVIY28=; b=ZDpHAovhXmZrs6wo4A4mAmlJCeI4o+oo0L03c1LMe29/MF+JTc3FqDtBqIyNzA8KnubLZIfQUKFJCAN+zLbOdbx5sODvWZOHwAcuKGwzxxRcdGV3svYYFnxO93FGAQwHAYkUuxPVBrDPvMcoIgJb5RqVwkhGyAURqeqTK+vbaCE= ARC-Authentication-Results: i=1; mx.zoho.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 header.from= (p=none dis=none) header.from= Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1564052296599416.0233224175606; Thu, 25 Jul 2019 03:58:16 -0700 (PDT) Received: from localhost ([::1]:58586 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hqbRv-0001JJ-DP for importer@patchew.org; Thu, 25 Jul 2019 06:58:15 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:41109) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hqbRG-00078E-VU for qemu-devel@nongnu.org; Thu, 25 Jul 2019 06:57:36 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hqbRF-0006Cm-Tt for qemu-devel@nongnu.org; Thu, 25 Jul 2019 06:57:34 -0400 Received: from mx1.redhat.com ([209.132.183.28]:50260) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hqbRF-0006Av-Lt for qemu-devel@nongnu.org; Thu, 25 Jul 2019 06:57:33 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id F3423330265; Thu, 25 Jul 2019 10:57:32 +0000 (UTC) Received: from localhost.localdomain (ovpn-117-190.ams2.redhat.com [10.36.117.190]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7AC5A19C7F; Thu, 25 Jul 2019 10:57:30 +0000 (UTC) From: Juan Quintela To: qemu-devel@nongnu.org Date: Thu, 25 Jul 2019 12:57:21 +0200 Message-Id: <20190725105724.2562-2-quintela@redhat.com> In-Reply-To: <20190725105724.2562-1-quintela@redhat.com> References: <20190725105724.2562-1-quintela@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Thu, 25 Jul 2019 10:57:33 +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] [PULL 1/4] migration: fix migrate_cancel leads live_migration thread endless loop X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Laurent Vivier , Thomas Huth , kvm@vger.kernel.org, Juan Quintela , "Dr. David Alan Gilbert" , Ivan Ren , Paolo Bonzini , Ivan Ren , Richard Henderson Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" Content-Type: text/plain; charset="utf-8" From: Ivan Ren When we 'migrate_cancel' a multifd migration, live_migration thread may go into endless loop in multifd_send_pages functions. Reproduce steps: (qemu) migrate_set_capability multifd on (qemu) migrate -d url (qemu) [wait a while] (qemu) migrate_cancel Then may get live_migration 100% cpu usage in following stack: pthread_mutex_lock qemu_mutex_lock_impl multifd_send_pages multifd_queue_page ram_save_multifd_page ram_save_target_page ram_save_host_page ram_find_and_save_block ram_find_and_save_block ram_save_iterate qemu_savevm_state_iterate migration_iteration_run migration_thread qemu_thread_start start_thread clone Signed-off-by: Ivan Ren Message-Id: <1561468699-9819-2-git-send-email-ivanren@tencent.com> Reviewed-by: Dr. David Alan Gilbert Reviewed-by: Juan Quintela Signed-off-by: Juan Quintela --- migration/ram.c | 36 +++++++++++++++++++++++++++++------- 1 file changed, 29 insertions(+), 7 deletions(-) diff --git a/migration/ram.c b/migration/ram.c index 2b0774c2bf..52a2d498e4 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -920,7 +920,7 @@ struct { * false. */ =20 -static void multifd_send_pages(void) +static int multifd_send_pages(void) { int i; static int next_channel; @@ -933,6 +933,11 @@ static void multifd_send_pages(void) p =3D &multifd_send_state->params[i]; =20 qemu_mutex_lock(&p->mutex); + if (p->quit) { + error_report("%s: channel %d has already quit!", __func__, i); + qemu_mutex_unlock(&p->mutex); + return -1; + } if (!p->pending_job) { p->pending_job++; next_channel =3D (i + 1) % migrate_multifd_channels(); @@ -951,9 +956,11 @@ static void multifd_send_pages(void) ram_counters.transferred +=3D transferred;; qemu_mutex_unlock(&p->mutex); qemu_sem_post(&p->sem); + + return 1; } =20 -static void multifd_queue_page(RAMBlock *block, ram_addr_t offset) +static int multifd_queue_page(RAMBlock *block, ram_addr_t offset) { MultiFDPages_t *pages =3D multifd_send_state->pages; =20 @@ -968,15 +975,19 @@ static void multifd_queue_page(RAMBlock *block, ram_a= ddr_t offset) pages->used++; =20 if (pages->used < pages->allocated) { - return; + return 1; } } =20 - multifd_send_pages(); + if (multifd_send_pages() < 0) { + return -1; + } =20 if (pages->block !=3D block) { - multifd_queue_page(block, offset); + return multifd_queue_page(block, offset); } + + return 1; } =20 static void multifd_send_terminate_threads(Error *err) @@ -1049,7 +1060,10 @@ static void multifd_send_sync_main(void) return; } if (multifd_send_state->pages->used) { - multifd_send_pages(); + if (multifd_send_pages() < 0) { + error_report("%s: multifd_send_pages fail", __func__); + return; + } } for (i =3D 0; i < migrate_multifd_channels(); i++) { MultiFDSendParams *p =3D &multifd_send_state->params[i]; @@ -1058,6 +1072,12 @@ static void multifd_send_sync_main(void) =20 qemu_mutex_lock(&p->mutex); =20 + if (p->quit) { + error_report("%s: channel %d has already quit", __func__, i); + qemu_mutex_unlock(&p->mutex); + return; + } + p->packet_num =3D multifd_send_state->packet_num++; p->flags |=3D MULTIFD_FLAG_SYNC; p->pending_job++; @@ -2033,7 +2053,9 @@ static int ram_save_page(RAMState *rs, PageSearchStat= us *pss, bool last_stage) static int ram_save_multifd_page(RAMState *rs, RAMBlock *block, ram_addr_t offset) { - multifd_queue_page(block, offset); + if (multifd_queue_page(block, offset) < 0) { + return -1; + } ram_counters.normal++; =20 return 1; --=20 2.21.0