Messages in this thread Patch in this message | | | From | Kamal Mostafa <> | Subject | [PATCH 63/75] tuntap: correctly linearize skb when zerocopy is used | Date | Tue, 30 Jul 2013 11:45:07 -0700 |
| |
3.8.13.6 -stable review patch. If anyone has any objections, please let me know.
------------------
From: Jason Wang <jasowang@redhat.com>
[ Upstream commit 3dd5c3308e8b671e8e8882ba972f51cefbe9fd0d ]
Userspace may produce vectors greater than MAX_SKB_FRAGS. When we try to linearize parts of the skb to let the rest of iov to be fit in the frags, we need count copylen into linear when calling tun_alloc_skb() instead of partly counting it into data_len. Since this breaks zerocopy_sg_from_iovec() since its inner counter assumes nr_frags should be zero at beginning. This cause nr_frags to be increased wrongly without setting the correct frags.
This bug were introduced from 0690899b4d4501b3505be069b9a687e68ccbe15b (tun: experimental zero copy tx support)
Cc: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- drivers/net/tun.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 2a56317..0ebfa18 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1045,7 +1045,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, { struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) }; struct sk_buff *skb; - size_t len = total_len, align = NET_SKB_PAD; + size_t len = total_len, align = NET_SKB_PAD, linear; struct virtio_net_hdr gso = { 0 }; int offset = 0; int copylen; @@ -1109,10 +1109,13 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, copylen = gso.hdr_len; if (!copylen) copylen = GOODCOPY_LEN; - } else + linear = copylen; + } else { copylen = len; + linear = gso.hdr_len; + } - skb = tun_alloc_skb(tfile, align, copylen, gso.hdr_len, noblock); + skb = tun_alloc_skb(tfile, align, copylen, linear, noblock); if (IS_ERR(skb)) { if (PTR_ERR(skb) != -EAGAIN) tun->dev->stats.rx_dropped++; -- 1.8.1.2
| |