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 CFFA8CD128A for ; Tue, 9 Apr 2024 19:06:31 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ruGn6-0003mt-NK; Tue, 09 Apr 2024 15:05:56 -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 1ruGmv-0003mW-CD for qemu-devel@nongnu.org; Tue, 09 Apr 2024 15:05:47 -0400 Received: from mail-wr1-x436.google.com ([2a00:1450:4864:20::436]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1ruGmt-0007ng-Hd for qemu-devel@nongnu.org; Tue, 09 Apr 2024 15:05:45 -0400 Received: by mail-wr1-x436.google.com with SMTP id ffacd0b85a97d-343e7c20686so3306956f8f.1 for ; Tue, 09 Apr 2024 12:05:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1712689542; x=1713294342; darn=nongnu.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=IhLPEdtbq6jDpbKbP02h1k6WxT0ukK1avtaorQ2oyrc=; b=m3kIzx7VVOTkU5bP+2uWUT3DWc0lfFxCCMK3Zf0viyq7RhMB93ZpIaMCmr68baGZH1 FG1Inva46OrDqTxZiCXUM5+p9pPaSanChO8U/x1wuMB+37p1EL7Lii9MFgTktR3XiFlN SeivWiWpP8x5WYZSvtUEMBgCcwLAYwWWcQ788uMqNIj7BJLJGnoPei2nJ64AeZz0okHj GT9u8+vGOmhs0Qc+mGlaHfwHhZRTCtp5GQ2Pk+ocf6AeVgi6QIT7hcol+Y09mO79bsPM O5rw+C4Ork/IqI/x1xk6Q5q8dFPXYG+kxhS3JxduSUlnt1w0GHQnLySMocSkPosPwXCX qrFw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1712689542; x=1713294342; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=IhLPEdtbq6jDpbKbP02h1k6WxT0ukK1avtaorQ2oyrc=; b=ebPQfMoOQkduHkXkR279GVdV/ha+HSpjXIRLmp8v34CJWCXeHaFwEuQ8nfh2rNIsLW wGwoyW/hqLV0XchZBh8ABTL3AYnLg0GjnDpSgABdNuEkDQLbdAEXhoSt/ch6mz+S8ZXu r6MrwmvVjqUuGa+2xQd/eFbwZYxRHHx4YUF/a3ujlqfV3XuUzLXPvZ+NjEsESxF+CuRG 0wvHsunFW7yaER/bmpe976GZyy4iJ+wQ8J1SZT10W4Ys1GGJdPC8FEQrJtWWVwrI9G/a WYzqALKXW97fWQqEIyg4wQVKMAkAJ3hy1UyYzbZZnCEMQBBeh8eHR6HAiAIssb2f12Ol b3tA== X-Gm-Message-State: AOJu0Yy1UU/iLBzPYYb5kR4HbzrBiGjArz/MHEqhEkmZwI/I/Td5tA2q I48qdtw+Lnv6tJBKKRiLcDBKIDltWOmjclqHNx+VBchUQeBvihCKcGtrKG/gRA== X-Google-Smtp-Source: AGHT+IHaVvcmkQnuNnl583wHjEWc+goP/J7wmxjuouFLoiDTftLWI+vMjnckjt1Q0WTl50rCaj+OgQ== X-Received: by 2002:a05:6000:1743:b0:345:bbf8:5587 with SMTP id m3-20020a056000174300b00345bbf85587mr396264wrf.8.1712689541680; Tue, 09 Apr 2024 12:05:41 -0700 (PDT) Received: from localhost.localdomain ([46.53.249.134]) by smtp.gmail.com with ESMTPSA id j11-20020adff54b000000b003433bf6651dsm11378044wrp.75.2024.04.09.12.05.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 09 Apr 2024 12:05:41 -0700 (PDT) From: Alexey Dobriyan To: qemu-devel@nongnu.org Cc: adobriyan@gmail.com, adobriyan@yandex-team.ru, mst@redhat.com, jasowang@redhat.com, vsementsov@yandex-team.ru Subject: [PATCH 1/1] virtio-net: fix bug 1451 aka "assert(!virtio_net_get_subqueue(nc)->async_tx.elem); " Date: Tue, 9 Apr 2024 22:05:22 +0300 Message-ID: <20240409190522.101658-1-adobriyan@gmail.com> X-Mailer: git-send-email 2.43.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=2a00:1450:4864:20::436; envelope-from=adobriyan@gmail.com; helo=mail-wr1-x436.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_NONE=-0.0001, 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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Reproducer from https://gitlab.com/qemu-project/qemu/-/issues/1451 creates small packet (1 segment, len=10 == n->guest_hdr_len), destroys queue. "if (n->host_hdr_len != n->guest_hdr_len)" is triggered. There is nothing after guest header, if body creates zero length/zero segment packet. qemu_sendv_packet_async() tries to send it. Packet is discarded inside net_slirp_receive() which returns number of sent bytes which is 0. 0 is propagated upwards and is interpreted as "zero bytes has been sent" which is terrible because queue is being destroyed, nobody is waiting for TX to complete, TX complete hook is _not_ called and assert(async_tx.elem) is eventually triggered. The fix is to discard such phantom packets in virtio_net_flush_tx(). Signed-off-by: Alexey Dobriyan --- hw/net/virtio-net.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c index 58014a92ad..e156f1d78c 100644 --- a/hw/net/virtio-net.c +++ b/hw/net/virtio-net.c @@ -2765,18 +2765,14 @@ static int32_t virtio_net_flush_tx(VirtIONetQueue *q) out_sg = elem->out_sg; if (out_num < 1) { virtio_error(vdev, "virtio-net header not in first element"); - virtqueue_detach_element(q->tx_vq, elem, 0); - g_free(elem); - return -EINVAL; + goto detach; } if (n->has_vnet_hdr) { if (iov_to_buf(out_sg, out_num, 0, &vhdr, n->guest_hdr_len) < n->guest_hdr_len) { virtio_error(vdev, "virtio-net header incorrect"); - virtqueue_detach_element(q->tx_vq, elem, 0); - g_free(elem); - return -EINVAL; + goto detach; } if (n->needs_vnet_hdr_swap) { virtio_net_hdr_swap(vdev, (void *) &vhdr); @@ -2807,6 +2803,11 @@ static int32_t virtio_net_flush_tx(VirtIONetQueue *q) n->guest_hdr_len, -1); out_num = sg_num; out_sg = sg; + + if (out_num < 1) { + virtio_error(vdev, "virtio-net nothing to send"); + goto detach; + } } ret = qemu_sendv_packet_async(qemu_get_subqueue(n->nic, queue_index), @@ -2827,6 +2828,11 @@ drop: } } return num_packets; + +detach: + virtqueue_detach_element(q->tx_vq, elem, 0); + g_free(elem); + return -EINVAL; } static void virtio_net_tx_timer(void *opaque); -- 2.43.0