From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1032830Ab2I1Uao (ORCPT ); Fri, 28 Sep 2012 16:30:44 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:34785 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965024Ab2I1Uaj (ORCPT ); Fri, 28 Sep 2012 16:30:39 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , alan@lxorguk.ukuu.org.uk, Jason Wang , "Michael S. Tsirkin" , Ben Hutchings Subject: [ 170/218] macvtap: zerocopy: set SKBTX_DEV_ZEROCOPY only when skb is built successfully Date: Fri, 28 Sep 2012 13:16:27 -0700 Message-Id: <20120928201521.045295346@linuxfoundation.org> X-Mailer: git-send-email 1.7.12.1.428.g652398a In-Reply-To: <20120928201501.208384923@linuxfoundation.org> References: <20120928201501.208384923@linuxfoundation.org> User-Agent: quilt/0.60-2.1.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jason Wang commit 01d6657b388438def19c8baaea28e742b6ed32ec upstream. Current the SKBTX_DEV_ZEROCOPY is set unconditionally after zerocopy_sg_from_iovec(), this would lead NULL pointer when macvtap fails to build zerocopy skb because destructor_arg was not initialized. Solve this by set this flag after the skb were built successfully. Signed-off-by: Jason Wang Signed-off-by: Michael S. Tsirkin Cc: Ben Hutchings Signed-off-by: Greg Kroah-Hartman --- drivers/net/macvtap.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) --- a/drivers/net/macvtap.c +++ b/drivers/net/macvtap.c @@ -716,10 +716,9 @@ static ssize_t macvtap_get_user(struct m if (!skb) goto err; - if (zerocopy) { + if (zerocopy) err = zerocopy_sg_from_iovec(skb, iv, vnet_hdr_len, count); - skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY; - } else + else err = skb_copy_datagram_from_iovec(skb, 0, iv, vnet_hdr_len, len); if (err) @@ -738,8 +737,10 @@ static ssize_t macvtap_get_user(struct m rcu_read_lock_bh(); vlan = rcu_dereference_bh(q->vlan); /* copy skb_ubuf_info for callback when skb has no error */ - if (zerocopy) + if (zerocopy) { skb_shinfo(skb)->destructor_arg = m->msg_control; + skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY; + } if (vlan) macvlan_start_xmit(skb, vlan->dev); else