From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg Kroah-Hartman Subject: [PATCH 3.15 076/109] xen-netback: Fix releasing frag_list skbs in error path Date: Sat, 26 Jul 2014 12:02:38 -0700 Message-ID: <20140726190226.160782147@linuxfoundation.org> References: <20140726190223.834037485@linuxfoundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Zoltan Kiss , Armin Zentai , netdev@vger.kernel.org, xen-devel@lists.xenproject.org, "David S. Miller" To: linux-kernel@vger.kernel.org Return-path: In-Reply-To: <20140726190223.834037485@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org 3.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Zoltan Kiss [ Upstream commit b42cc6e421e7bf74e545483aa34b99d2a2ca6d3a ] When the grant operations failed, the skb is freed up eventually, and it tries to release the frags, if there is any. For the main skb nr_frags is set to 0 to avoid this, but on the frag_list it iterates through the frags array, and tries to call put_page on the page pointer which contains garbage at that time. Signed-off-by: Zoltan Kiss Reported-by: Armin Zentai Cc: netdev@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: xen-devel@lists.xenproject.org Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/xen-netback/netback.c | 9 +++++++++ 1 file changed, 9 insertions(+) --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -1498,7 +1498,16 @@ static int xenvif_tx_submit(struct xenvi /* Check the remap error code. */ if (unlikely(xenvif_tx_check_gop(vif, skb, &gop_map, &gop_copy))) { + /* If there was an error, xenvif_tx_check_gop is + * expected to release all the frags which were mapped, + * so kfree_skb shouldn't do it again + */ skb_shinfo(skb)->nr_frags = 0; + if (skb_has_frag_list(skb)) { + struct sk_buff *nskb = + skb_shinfo(skb)->frag_list; + skb_shinfo(nskb)->nr_frags = 0; + } kfree_skb(skb); continue; }