Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754724AbaGUKlV (ORCPT ); Mon, 21 Jul 2014 06:41:21 -0400 Received: from smtp.citrix.com ([66.165.176.89]:23103 "EHLO SMTP.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754350AbaGUKlT (ORCPT ); Mon, 21 Jul 2014 06:41:19 -0400 X-IronPort-AV: E=Sophos;i="5.01,699,1400025600"; d="scan'208";a="154165753" From: Zoltan Kiss To: Wei Liu , Ian Campbell CC: Zoltan Kiss , , , Subject: [PATCH for stable 3.15 2/4 v2] xen-netback: Fix releasing frag_list skbs in error path Date: Mon, 21 Jul 2014 11:41:00 +0100 Message-ID: <1405939262-7944-2-git-send-email-zoltan.kiss@citrix.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1405939262-7944-1-git-send-email-zoltan.kiss@citrix.com> References: <1405939262-7944-1-git-send-email-zoltan.kiss@citrix.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.80.2.133] X-DLP: MIA1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- v2: adding comment diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c index 9b0f482..75b7d1a 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; } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/