From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752199AbdHPOOm (ORCPT ); Wed, 16 Aug 2017 10:14:42 -0400 Received: from mx1.redhat.com ([209.132.183.28]:38539 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752027AbdHPOOl (ORCPT ); Wed, 16 Aug 2017 10:14:41 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 10F5CC0467D7 Authentication-Results: ext-mx07.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx07.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=jasowang@redhat.com From: Jason Wang To: davem@davemloft.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Cc: mst@redhat.com, Eric Dumazet , Jason Wang Subject: [PATCH] tun: make tun_build_skb() thread safe Date: Wed, 16 Aug 2017 22:14:33 +0800 Message-Id: <1502892873-10770-1-git-send-email-jasowang@redhat.com> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Wed, 16 Aug 2017 14:14:41 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Eric Dumazet tun_build_skb() is not thread safe since it uses per queue page frag, this will break things when multiple threads are sending through same queue. Switch to use per-thread generator (no lock involved). Fixes: 66ccbc9c87c2 ("tap: use build_skb() for small packet") Tested-by: Jason Wang Signed-off-by: Eric Dumazet Signed-off-by: Jason Wang --- drivers/net/tun.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 5892284..c38cd84 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -175,7 +175,6 @@ struct tun_file { struct list_head next; struct tun_struct *detached; struct skb_array tx_array; - struct page_frag alloc_frag; }; struct tun_flow_entry { @@ -578,8 +577,6 @@ static void __tun_detach(struct tun_file *tfile, bool clean) } if (tun) skb_array_cleanup(&tfile->tx_array); - if (tfile->alloc_frag.page) - put_page(tfile->alloc_frag.page); sock_put(&tfile->sk); } } @@ -1272,7 +1269,7 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun, struct virtio_net_hdr *hdr, int len, int *generic_xdp) { - struct page_frag *alloc_frag = &tfile->alloc_frag; + struct page_frag *alloc_frag = ¤t->task_frag; struct sk_buff *skb; struct bpf_prog *xdp_prog; int buflen = SKB_DATA_ALIGN(len + TUN_RX_PAD) + @@ -2580,8 +2577,6 @@ static int tun_chr_open(struct inode *inode, struct file * file) tfile->sk.sk_write_space = tun_sock_write_space; tfile->sk.sk_sndbuf = INT_MAX; - tfile->alloc_frag.page = NULL; - file->private_data = tfile; INIT_LIST_HEAD(&tfile->next); -- 2.7.4