From patchwork Wed Jan 29 11:15:25 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Juan Quintela X-Patchwork-Id: 11355905 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 4C2A914B7 for ; Wed, 29 Jan 2020 11:23:43 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 2301520708 for ; Wed, 29 Jan 2020 11:23:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="dQt1OW6J" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2301520708 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Received: from localhost ([::1]:44546 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iwlRe-0005wf-BI for patchwork-qemu-devel@patchwork.kernel.org; Wed, 29 Jan 2020 06:23:42 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:60274) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iwlKu-0002XJ-Qa for qemu-devel@nongnu.org; Wed, 29 Jan 2020 06:16:46 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iwlKt-0006fP-Ky for qemu-devel@nongnu.org; Wed, 29 Jan 2020 06:16:44 -0500 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:58737 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iwlKR-0006Tv-Nl for qemu-devel@nongnu.org; Wed, 29 Jan 2020 06:16:43 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1580296575; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=uQoCp+lsDv7BBjx8uaBMQWgkPzFniwH4ongsNqa/KJM=; b=dQt1OW6JULjEI+FDVunLJyxchIRALS0C8pyr1ovYW0DEbg/7wZKpsM94m11k0nuDyQXuu/ Nz2O2ECW2OdxI40PMXQW1NYxb/SszL8YisxuS4XHCbG/UMjow81iBrGNMcuRnWHid9TJuR k6Jn06c2Z13MxgVH21tB+xDGQ9ZGpf0= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-131-cLX84KbfNfKPfHX4YlKzBQ-1; Wed, 29 Jan 2020 06:16:13 -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 mimecast-mx01.redhat.com (Postfix) with ESMTPS id EB168107B7F6; Wed, 29 Jan 2020 11:16:11 +0000 (UTC) Received: from secure.mitica (ovpn-116-64.ams2.redhat.com [10.36.116.64]) by smtp.corp.redhat.com (Postfix) with ESMTP id 94DBB89D2E; Wed, 29 Jan 2020 11:15:58 +0000 (UTC) From: Juan Quintela To: qemu-devel@nongnu.org Subject: [PULL 07/18] migration/multifd: fix nullptr access in multifd_send_terminate_threads Date: Wed, 29 Jan 2020 12:15:25 +0100 Message-Id: <20200129111536.9497-8-quintela@redhat.com> In-Reply-To: <20200129111536.9497-1-quintela@redhat.com> References: <20200129111536.9497-1-quintela@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-MC-Unique: cLX84KbfNfKPfHX4YlKzBQ-1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.81 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 , Juan Quintela , Zhimin Feng , "Dr. David Alan Gilbert" , Paolo Bonzini Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" From: Zhimin Feng If the multifd_send_threads is not created when migration is failed, multifd_save_cleanup would be called twice. In this senario, the multifd_send_state is accessed after it has been released, the result is that the source VM is crashing down. Here is the coredump stack: Program received signal SIGSEGV, Segmentation fault. 0x00005629333a78ef in multifd_send_terminate_threads (err=err@entry=0x0) at migration/ram.c:1012 1012 MultiFDSendParams *p = &multifd_send_state->params[i]; #0 0x00005629333a78ef in multifd_send_terminate_threads (err=err@entry=0x0) at migration/ram.c:1012 #1 0x00005629333ab8a9 in multifd_save_cleanup () at migration/ram.c:1028 #2 0x00005629333abaea in multifd_new_send_channel_async (task=0x562935450e70, opaque=) at migration/ram.c:1202 #3 0x000056293373a562 in qio_task_complete (task=task@entry=0x562935450e70) at io/task.c:196 #4 0x000056293373a6e0 in qio_task_thread_result (opaque=0x562935450e70) at io/task.c:111 #5 0x00007f475d4d75a7 in g_idle_dispatch () from /usr/lib64/libglib-2.0.so.0 #6 0x00007f475d4da9a9 in g_main_context_dispatch () from /usr/lib64/libglib-2.0.so.0 #7 0x0000562933785b33 in glib_pollfds_poll () at util/main-loop.c:219 #8 os_host_main_loop_wait (timeout=) at util/main-loop.c:242 #9 main_loop_wait (nonblocking=nonblocking@entry=0) at util/main-loop.c:518 #10 0x00005629334c5acf in main_loop () at vl.c:1810 #11 0x000056293334d7bb in main (argc=, argv=, envp=) at vl.c:4471 If the multifd_send_threads is not created when migration is failed. In this senario, we don't call multifd_save_cleanup in multifd_new_send_channel_async. Signed-off-by: Zhimin Feng Reviewed-by: Juan Quintela Signed-off-by: Juan Quintela --- migration/ram.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/migration/ram.c b/migration/ram.c index 3fd7fdffcf..82c7edb083 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -1233,7 +1233,15 @@ static void multifd_new_send_channel_async(QIOTask *task, gpointer opaque) trace_multifd_new_send_channel_async(p->id); if (qio_task_propagate_error(task, &local_err)) { migrate_set_error(migrate_get_current(), local_err); - multifd_save_cleanup(); + /* Error happen, we need to tell who pay attention to me */ + qemu_sem_post(&multifd_send_state->channels_ready); + qemu_sem_post(&p->sem_sync); + /* + * Although multifd_send_thread is not created, but main migration + * thread neet to judge whether it is running, so we need to mark + * its status. + */ + p->quit = true; } else { p->c = QIO_CHANNEL(sioc); qio_channel_set_delay(p->c, false);