From: Zoltan Kiss Date: Fri, 18 Jul 2014 18:08:03 +0000 (+0100) Subject: xen-netback: Fix releasing frag_list skbs in error path X-Git-Tag: v3.15.7~34 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=50b771050668d2df87f9f5488d860e9696a0a5fc;p=thirdparty%2Fkernel%2Fstable.git xen-netback: Fix releasing frag_list skbs in error path [ 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 --- diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c index 9b0f482fc8d07..75b7d1a1adadb 100644 --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -1498,7 +1498,16 @@ static int xenvif_tx_submit(struct xenvif *vif) /* 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; }