Messages in this thread Patch in this message | | | From | Zoltan Kiss <> | Subject | [PATCH net 2/4 v2] xen-netback: Fix releasing frag_list skbs in error path | Date | Fri, 18 Jul 2014 19:08:03 +0100 |
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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 <zoltan.kiss@citrix.com> Reported-by: Armin Zentai <armin.zentai@ezit.hu> 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 a773f20..8cbf60d 100644 --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -1521,7 +1521,16 @@ static int xenvif_tx_submit(struct xenvif_queue *queue) /* Check the remap error code. */ if (unlikely(xenvif_tx_check_gop(queue, 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; }
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