From patchwork Thu Oct 8 18:34:36 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jonathan Lemon X-Patchwork-Id: 268873 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.7 required=3.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 16C27C433DF for ; Thu, 8 Oct 2020 18:34:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BC73322200 for ; Thu, 8 Oct 2020 18:34:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729186AbgJHSen convert rfc822-to-8bit (ORCPT ); Thu, 8 Oct 2020 14:34:43 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:44790 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729162AbgJHSen (ORCPT ); Thu, 8 Oct 2020 14:34:43 -0400 Received: from pps.filterd (m0109333.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 098IUuXM000891 for ; Thu, 8 Oct 2020 11:34:43 -0700 Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com with ESMTP id 341wvrb66q-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Thu, 08 Oct 2020 11:34:42 -0700 Received: from intmgw001.08.frc2.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:83::5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1979.3; Thu, 8 Oct 2020 11:34:38 -0700 Received: by devvm2494.atn0.facebook.com (Postfix, from userid 172786) id 196F624751BE; Thu, 8 Oct 2020 11:34:36 -0700 (PDT) From: Jonathan Lemon To: , , CC: Subject: [PATCH net-next] virtio_net: handle non-napi callers to virtnet_poll_tx Date: Thu, 8 Oct 2020 11:34:36 -0700 Message-ID: <20201008183436.3093286-1-jonathan.lemon@gmail.com> X-Mailer: git-send-email 2.24.1 MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235, 18.0.687 definitions=2020-10-08_12:2020-10-08,2020-10-08 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 spamscore=0 clxscore=1034 mlxscore=0 lowpriorityscore=0 malwarescore=0 impostorscore=0 mlxlogscore=701 suspectscore=2 adultscore=0 bulkscore=0 priorityscore=1501 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2010080133 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Jonathan Lemon netcons will call napi_poll with a budget of 0, indicating a non-napi caller (and also called with irqs disabled). Call free_old_xmit_skbs() with the is_napi parameter set correctly. Found by this splat: WARNING: CPU: 2 PID: 1368 at net/core/skbuff.c:650 skb_release_head_state+0x7f/0x90 RIP: 0010:skb_release_head_state+0x7f/0x90 Code: e7 7f 08 00 80 7b 7f 00 74 f3 48 8b bb d8 00 00 00 5b e9 d4 f2 ff ff 48 83 e7 fe e8 bb f5 01 00 RSP: 0000:ffffc900000e4d18 EFLAGS: 00010006 RAX: ffffffff818fc470 RBX: ffff888235a36d00 RCX: ffff88822df23000 RDX: 0000000000010000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffff888235a36d00 R08: 0000000000000002 R09: 00000000ffffdd86 R10: 00000000ffffdd86 R11: 0000000000000000 R12: ffff8882367b4800 R13: 0000000000000001 R14: ffff8882367b4ac8 R15: ffff8882367b4ab8 FS: 00007fdc30f8a700(0000) GS:ffff888237d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fdc300ea000 CR3: 000000022992f001 CR4: 0000000000360ee0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: skb_release_all+0xe/0x30 napi_consume_skb+0x4c/0x110 free_old_xmit_skbs+0x3e/0xa0 [virtio_net] virtnet_poll_tx+0x7e/0xe0 [virtio_net] netpoll_poll_dev+0xba/0x190 netpoll_send_skb_on_dev+0x1e7/0x240 netpoll_send_udp+0x2b3/0x3d0 write_ext_msg+0x1be/0x1d0 console_unlock+0x227/0x4b0 vprintk_emit+0xe5/0x1b0 printk+0x58/0x6f smp_apic_timer_interrupt+0x5e/0x120 apic_timer_interrupt+0xf/0x20 Signed-off-by: Jonathan Lemon --- drivers/net/virtio_net.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 21b71148c532..59f65ac9e4c7 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -1518,7 +1518,7 @@ static int virtnet_poll_tx(struct napi_struct *napi, int budget) txq = netdev_get_tx_queue(vi->dev, index); __netif_tx_lock(txq, raw_smp_processor_id()); - free_old_xmit_skbs(sq, true); + free_old_xmit_skbs(sq, budget != 0); __netif_tx_unlock(txq); virtqueue_napi_complete(napi, sq->vq, 0);