This is a note to let you know that I've just added the patch titled
tuntap: correctly linearize skb when zerocopy is used
to the 3.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
tuntap-correctly-linearize-skb-when-zerocopy-is-used.patch
and it can be found in the queue-3.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 4782f7d41346ac49c6aa58ee9da6a7ff896cbe4c Mon Sep 17 00:00:00 2001
From: Jason Wang <jasowang@xxxxxxxxxx>
Date: Wed, 10 Jul 2013 13:43:27 +0800
Subject: tuntap: correctly linearize skb when zerocopy is used
From: Jason Wang <jasowang@xxxxxxxxxx>
[ 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@xxxxxxxxxx>
Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/tun.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1044,7 +1044,7 @@ static ssize_t tun_get_user(struct tun_s
{
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;
@@ -1108,10 +1108,13 @@ static ssize_t tun_get_user(struct tun_s
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++;
Patches currently in stable-queue which might be from jasowang@xxxxxxxxxx are
queue-3.10/macvtap-do-not-zerocopy-if-iov-needs-more-pages-than-max_skb_frags.patch
queue-3.10/vhost-net-fix-use-after-free-in-vhost_net_flush.patch
queue-3.10/virtio_net-fix-race-in-rx-vq-processing.patch
queue-3.10/macvtap-correctly-linearize-skb-when-zerocopy-is-used.patch
queue-3.10/tuntap-do-not-zerocopy-if-iov-needs-more-pages-than-max_skb_frags.patch
queue-3.10/tuntap-correctly-linearize-skb-when-zerocopy-is-used.patch
--
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