From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 99F1BC3DA4A for ; Thu, 8 Aug 2024 08:50:43 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1sbyqo-0003fn-JF; Thu, 08 Aug 2024 04:50:26 -0400 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 1sbyqn-0003fF-74 for qemu-devel@nongnu.org; Thu, 08 Aug 2024 04:50:25 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sbyql-0007fv-Em for qemu-devel@nongnu.org; Thu, 08 Aug 2024 04:50:24 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1723107022; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:in-reply-to:in-reply-to: references:references; bh=v6J6+UE9yoZgVAxKMzhrpg6GLnnB0hBvKEnUQ2lmG68=; b=hO60IvN5rO2TGVmi9sOyg8AmMOoqEdR0UUl/KnhHKOH/FMuUfWhwT52IVc5gZkl0EpAZFk p2EVsIZ7Z/YUbsGzLqHC7RiY85s2hDxH/LiJblgkR27SRD9LRsEc7aEndtjHgkZRwkSZL0 3KpIjTCtAvlnbLm529dY+R1jGJ/lHVA= Received: from mx-prod-mc-04.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-526-ZV18ngK2O1Kma1FLlgQt7Q-1; Thu, 08 Aug 2024 04:50:18 -0400 X-MC-Unique: ZV18ngK2O1Kma1FLlgQt7Q-1 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id B7E1E19560A2; Thu, 8 Aug 2024 08:50:16 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.163]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 15A5D19560A3; Thu, 8 Aug 2024 08:50:14 +0000 (UTC) Date: Thu, 8 Aug 2024 09:50:11 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: yaozhenguo Cc: qemu-devel@nongnu.org, yaozhenguo@jd.com Subject: Re: [PATCH] qio: fix qemu crash when live migration Message-ID: References: <20240808030411.76990-1-yaozhenguo@jd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20240808030411.76990-1-yaozhenguo@jd.com> User-Agent: Mutt/2.2.12 (2023-09-09) X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 Received-SPF: pass client-ip=170.10.133.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.144, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 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: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Thu, Aug 08, 2024 at 11:04:11AM +0800, yaozhenguo wrote: > qemu will crash in live migration cleanup process at source host. > BT is as below: > > 0 0x00007f740fc9e165 in g_source_destroy () at /usr/lib64/libglib-2.0.so.0 > 1 0x000055a2982a0f6e in qio_net_listener_set_client_func_full > 2 0x000055a298345130 in tcp_chr_update_read_handler > 3 0x000055a298341598 in qemu_chr_fe_set_handlers_full > 4 0x000055a298341655 in qemu_chr_fe_set_handlers > 5 0x000055a298191e75 in vhost_user_blk_event > 6 0x000055a298292b79 in object_deinit > 7 object_finalize > 8 object_unref > 9 0x000055a298292b3c in object_property_del_all > 10 object_finalize > 11 object_unref > 12 0x000055a298291d7d in object_property_del_child > 13 object_unparent > 14 0x000055a29834a3c4 in qemu_chr_cleanup > 15 0x000055a298160d87 in qemu_cleanup > 16 0x000055a297e6bff1 in main > > Crash reason is that qio_net_listener_finalize is called before > qio_net_listener_set_client_func_full. so, listener->io_source > is used after free. fix this by adding more checks. If finalize() has been called, then not only has listener->io_source been freed, but 'listener' itself has also been freed, thus.... > > Signed-off-by: yaozhenguo > --- > io/net-listener.c | 13 +++++++++++++ > 1 file changed, 13 insertions(+) > > diff --git a/io/net-listener.c b/io/net-listener.c > index 47405965a6..c02965f919 100644 > --- a/io/net-listener.c > +++ b/io/net-listener.c > @@ -143,6 +143,11 @@ void qio_net_listener_set_client_func_full(QIONetListener *listener, > { > size_t i; > > + > + if (!listener->nsioc || !listener->io_source || !listener->name) { > + return; > + } ....this is still accessing freed memory for 'listener'. What is the call path of the stack triggering qio_net_listener_finalize ? Whatever callpath has done that needs to be setting SocketChardev->listener field to NULL, because tcp_chr_update_read_handler will check for NULL before calling qio_net_listener_set_client_func_full. > + > if (listener->io_notify) { > listener->io_notify(listener->io_data); > } > @@ -264,6 +269,10 @@ void qio_net_listener_disconnect(QIONetListener *listener) > { > size_t i; > > + if (!listener->nsioc || !listener->io_source || !listener->name) { > + return; > + } > + > if (!listener->connected) { > return; > } > @@ -301,6 +310,10 @@ static void qio_net_listener_finalize(Object *obj) > g_free(listener->io_source); > g_free(listener->sioc); > g_free(listener->name); > + > + listener->io_source = NULL; > + listener->sioc = NULL; > + listener->name = NULL; > } > > static const TypeInfo qio_net_listener_info = { > -- > 2.43.0 > With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|