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dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:55612 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lZP2r-0007Z7-4f for qemu-devel@archiver.kernel.org; Wed, 21 Apr 2021 22:26:21 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:37824) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lZP28-00078p-LH for qemu-devel@nongnu.org; Wed, 21 Apr 2021 22:25:36 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:22672) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lZP26-0007qW-Ca for qemu-devel@nongnu.org; Wed, 21 Apr 2021 22:25:35 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1619058332; 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; 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Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.9.1 MIME-Version: 1.0 In-Reply-To: <3f6be9c84782a0943ea21a8a6f8a5d055b65f2d5.1619018363.git.crobinso@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=jasowang@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=gbk; format=flowed Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=216.205.24.124; envelope-from=jasowang@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -2 X-Spam_score: -0.3 X-Spam_bar: / X-Spam_report: (-0.3 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, MIME_CHARSET_FARAWAY=2.45, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_LOW=-0.7, 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: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Maydell Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" ÔÚ 2021/4/21 ÏÂÎç11:22, Cole Robinson дµÀ: > Attempting to hotplug a tap nic with libvirt will crash qemu: > > $ sudo virsh attach-interface f32 network default > error: Failed to attach interface > error: Unable to read from monitor: Connection reset by peer > > 0x000055875b7f3a99 in tap_send (opaque=0x55875e39eae0) at ../net/tap.c:206 > 206 if (!s->nc.peer->do_not_pad) { > gdb$ bt > > s->nc.peer may not be set at this point. This seems to be an > expected case, as qemu_send_packet_* explicitly checks for NULL > s->nc.peer later. > > Fix it by checking for s->nc.peer here too. Padding is applied if > s->nc.peer is not set. > > https://bugzilla.redhat.com/show_bug.cgi?id=1949786 > Fixes: 969e50b61a2 > > Signed-off-by: Cole Robinson > --- > * Or should we skip padding if nc.peer is unset? I think so, the padding is for the peer. > I didn't dig into it > * tap-win3.c and slirp.c may need a similar fix, but the slirp case > didn't crash in a simple test. Yes, the reason is because there's no packet go through slirp I think. Thanks. > > net/tap.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/net/tap.c b/net/tap.c > index dd42ac6134..937559dbb8 100644 > --- a/net/tap.c > +++ b/net/tap.c > @@ -203,7 +203,7 @@ static void tap_send(void *opaque) > size -= s->host_vnet_hdr_len; > } > > - if (!s->nc.peer->do_not_pad) { > + if (!s->nc.peer || !s->nc.peer->do_not_pad) { > if (eth_pad_short_frame(min_pkt, &min_pktsz, buf, size)) { > buf = min_pkt; > size = min_pktsz;