From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , Andrey Konovalov , Willem de Bruijn , "David S. Miller" Subject: [PATCH 4.10 107/129] net: adjust skb->truesize in ___pskb_trim() Date: Thu, 11 May 2017 16:12:35 +0200 Message-Id: <20170511141226.892886076@linuxfoundation.org> In-Reply-To: <20170511141220.039886885@linuxfoundation.org> References: <20170511141220.039886885@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit c21b48cc1bbf2f5af3ef54ada559f7fadf8b508b ] Andrey found a way to trigger the WARN_ON_ONCE(delta < len) in skb_try_coalesce() using syzkaller and a filter attached to a TCP socket. As we did recently in commit 158f323b9868 ("net: adjust skb->truesize in pskb_expand_head()") we can adjust skb->truesize from ___pskb_trim(), via a call to skb_condense(). If all frags were freed, then skb->truesize can be recomputed. This call can be done if skb is not yet owned, or destructor is sock_edemux(). Signed-off-by: Eric Dumazet Reported-by: Andrey Konovalov Cc: Willem de Bruijn Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/core/skbuff.c | 2 ++ 1 file changed, 2 insertions(+) --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -1572,6 +1572,8 @@ done: skb_set_tail_pointer(skb, len); } + if (!skb->sk || skb->destructor == sock_edemux) + skb_condense(skb); return 0; } EXPORT_SYMBOL(___pskb_trim);