From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:53346 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750952AbdEaAQa (ORCPT ); Tue, 30 May 2017 20:16:30 -0400 Subject: Patch "netem: fix skb_orphan_partial()" has been added to the 4.11-stable tree To: edumazet@google.com, davem@davemloft.net, gregkh@linuxfoundation.org, mkm@nabto.com Cc: , From: Date: Wed, 31 May 2017 09:14:24 +0900 Message-ID: <1496189664120107@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled netem: fix skb_orphan_partial() to the 4.11-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: netem-fix-skb_orphan_partial.patch and it can be found in the queue-4.11 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From foo@baz Wed May 31 09:13:10 JST 2017 From: Eric Dumazet Date: Thu, 11 May 2017 15:24:41 -0700 Subject: netem: fix skb_orphan_partial() From: Eric Dumazet [ Upstream commit f6ba8d33cfbb46df569972e64dbb5bb7e929bfd9 ] I should have known that lowering skb->truesize was dangerous :/ In case packets are not leaving the host via a standard Ethernet device, but looped back to local sockets, bad things can happen, as reported by Michael Madsen ( https://bugzilla.kernel.org/show_bug.cgi?id=195713 ) So instead of tweaking skb->truesize, lets change skb->destructor and keep a reference on the owner socket via its sk_refcnt. Fixes: f2f872f9272a ("netem: Introduce skb_orphan_partial() helper") Signed-off-by: Eric Dumazet Reported-by: Michael Madsen Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/core/sock.c | 20 ++++++++------------ 1 file changed, 8 insertions(+), 12 deletions(-) --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1699,28 +1699,24 @@ EXPORT_SYMBOL(skb_set_owner_w); * delay queue. We want to allow the owner socket to send more * packets, as if they were already TX completed by a typical driver. * But we also want to keep skb->sk set because some packet schedulers - * rely on it (sch_fq for example). So we set skb->truesize to a small - * amount (1) and decrease sk_wmem_alloc accordingly. + * rely on it (sch_fq for example). */ void skb_orphan_partial(struct sk_buff *skb) { - /* If this skb is a TCP pure ACK or already went here, - * we have nothing to do. 2 is already a very small truesize. - */ - if (skb->truesize <= 2) + if (skb_is_tcp_pure_ack(skb)) return; - /* TCP stack sets skb->ooo_okay based on sk_wmem_alloc, - * so we do not completely orphan skb, but transfert all - * accounted bytes but one, to avoid unexpected reorders. - */ if (skb->destructor == sock_wfree #ifdef CONFIG_INET || skb->destructor == tcp_wfree #endif ) { - atomic_sub(skb->truesize - 1, &skb->sk->sk_wmem_alloc); - skb->truesize = 1; + struct sock *sk = skb->sk; + + if (atomic_inc_not_zero(&sk->sk_refcnt)) { + atomic_sub(skb->truesize, &sk->sk_wmem_alloc); + skb->destructor = sock_efree; + } } else { skb_orphan(skb); } Patches currently in stable-queue which might be from edumazet@google.com are queue-4.11/ipv6-fix-out-of-bound-writes-in-__ip6_append_data.patch queue-4.11/tcp-eliminate-negative-reordering-in-tcp_clean_rtx_queue.patch queue-4.11/dccp-tcp-do-not-inherit-mc_list-from-parent.patch queue-4.11/tcp-avoid-fragmenting-peculiar-skbs-in-sack.patch queue-4.11/netem-fix-skb_orphan_partial.patch queue-4.11/net-fix-compile-error-in-skb_orphan_partial.patch queue-4.11/ipv6-dccp-do-not-inherit-ipv6_mc_list-from-parent.patch queue-4.11/sctp-do-not-inherit-ipv6_-mc-ac-fl-_list-from-parent.patch queue-4.11/ipv4-add-reference-counting-to-metrics.patch queue-4.11/tcp-avoid-fastopen-api-to-be-used-on-af_unspec.patch