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 <[email protected]> Reported-by: Armin Zentai <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] --- 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 [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
