* tun issue after e0b46d0ee9c: tun: Use iovec iterators
@ 2014-11-28 19:25 Marcelo Ricardo Leitner
2014-11-28 20:37 ` Al Viro
2014-11-28 23:59 ` Herbert Xu
0 siblings, 2 replies; 12+ messages in thread
From: Marcelo Ricardo Leitner @ 2014-11-28 19:25 UTC (permalink / raw)
To: herbert; +Cc: netdev
Hi,
I saw there are tun updates on Dave's queue but none seemed to handle this.
I can't use current net-next (799d2fff1858004526ad75d66a5dd8a5cce6ad40) on a
kvm hypervisor because tun got clogged somehow. Bisected down to:
commit e0b46d0ee9c240c7430a47e9b0365674d4a04522
Author: Herbert Xu <herbert@gondor.apana.org.au>
Date: Fri Nov 7 21:22:23 2014 +0800
tun: Use iovec iterators
This patch removes the use of skb_copy_datagram_const_iovec in
favour of the iovec iterator-based skb_copy_datagram_iter.
tun interface, host drops 1 incoming packets from guest, shown at ip -s l l,
and keeps like that forever. netstat -s didn't mention any checksum issue
12: vnet0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master
virbr0 state UNKNOWN mode DEFAULT group default qlen 500
link/ether fe:54:00:10:3f:06 brd ff:ff:ff:ff:ff:ff
RX: bytes packets errors dropped overrun mcast
0 0 0 1 0 0
TX: bytes packets errors dropped carrier collsns
2704 51 0 0 0 0
And tap interfaces go counting dropped++ every time:
20: tap0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master
virbr0 state UNKNOWN mode DEFAULT group default qlen 500
link/ether fe:97:a4:a6:14:65 brd ff:ff:ff:ff:ff:ff
RX: bytes packets errors dropped overrun mcast
0 0 0 16 0 0
TX: bytes packets errors dropped carrier collsns
1456 28 0 0 0 0
traffic capture on guest shows incoming and outgoing packets just fine, while
on host, it shows no incoming packets at all.
Tested with virtio_net and e1000.
With:
tun.c tun_get_user():
if (zerocopy)
err = zerocopy_sg_from_iter(skb, from);
else {
err = skb_copy_datagram_from_iter(skb, 0, from, len); <- fails
if (!err && msg_control) {
struct ubuf_info *uarg = msg_control;
uarg->callback(uarg, false);
}
}
if (err) {
tun->dev->stats.rx_dropped++;
kfree_skb(skb);
pr_err("%d %d %d %p\n", __LINE__, zerocopy, err, msg_control);
return -EFAULT;
}
And net/core/datagram.c, skb_copy_datagram_from_iter():
if (copy > 0) {
int ret;
if (copy > len)
copy = len;
ret = copy_from_iter(skb->data + offset, copy, from);
if (ret != copy) {
pr_err("%d ret=%d copy=%d offset=%d len=%d\n",
__LINE__, ret, copy, offset, len);
goto fault;
}
I get, for tun interfaces:
[ 75.435552] 506 ret=80 copy=90 offset=0 len=90
[ 75.435563] tun: 1124 0 -14 (null)
[ 75.499528] 506 ret=80 copy=90 offset=0 len=90
[ 75.499540] tun: 1124 0 -14 (null)
These were 1 drop on 1 interface each
And for tap interfaces:
[ 301.982639] 506 ret=80 copy=90 offset=0 len=90
[ 301.982649] tun: 1124 0 -14 (null)
[ 301.988625] 506 ret=80 copy=90 offset=0 len=90
[ 301.988635] tun: 1124 0 -14 (null)
[ 301.994762] 506 ret=80 copy=90 offset=0 len=90
[ 301.994773] tun: 1124 0 -14 (null)
[ 302.229962] 506 ret=332 copy=342 offset=0 len=342
[ 302.229972] tun: 1124 0 -14 (null)
[ 302.230621] 506 ret=332 copy=342 offset=0 len=342
[ 302.230627] tun: 1124 0 -14 (null)
[ 302.239065] 506 ret=332 copy=342 offset=0 len=342
[ 302.239071] tun: 1124 0 -14 (null)
It's returning 10 bytes less than the expected... ideas?
I can provide more info if needed, it's easy to reproduce in here.
Thanks,
Marcelo
^ permalink raw reply [flat|nested] 12+ messages in thread* Re: tun issue after e0b46d0ee9c: tun: Use iovec iterators
2014-11-28 19:25 tun issue after e0b46d0ee9c: tun: Use iovec iterators Marcelo Ricardo Leitner
@ 2014-11-28 20:37 ` Al Viro
2014-11-28 22:10 ` Marcelo Ricardo Leitner
2014-11-28 23:59 ` Herbert Xu
1 sibling, 1 reply; 12+ messages in thread
From: Al Viro @ 2014-11-28 20:37 UTC (permalink / raw)
To: Marcelo Ricardo Leitner; +Cc: herbert, netdev
On Fri, Nov 28, 2014 at 05:25:27PM -0200, Marcelo Ricardo Leitner wrote:
> Hi,
>
> I saw there are tun updates on Dave's queue but none seemed to handle this.
>
> I can't use current net-next
> (799d2fff1858004526ad75d66a5dd8a5cce6ad40) on a kvm hypervisor
> because tun got clogged somehow. Bisected down to:
Umm... In host, presumably?
> And net/core/datagram.c, skb_copy_datagram_from_iter():
> if (copy > 0) {
> int ret;
> if (copy > len)
> copy = len;
> ret = copy_from_iter(skb->data + offset, copy, from);
> if (ret != copy) {
> pr_err("%d ret=%d copy=%d offset=%d
> len=%d\n", __LINE__, ret, copy, offset, len);
> goto fault;
> }
>
>
> I get, for tun interfaces:
> [ 75.435552] 506 ret=80 copy=90 offset=0 len=90
> [ 75.435563] tun: 1124 0 -14 (null)
> [ 75.499528] 506 ret=80 copy=90 offset=0 len=90
> [ 75.499540] tun: 1124 0 -14 (null)
>
> These were 1 drop on 1 interface each
>
> And for tap interfaces:
> [ 301.982639] 506 ret=80 copy=90 offset=0 len=90
> [ 301.982649] tun: 1124 0 -14 (null)
> [ 301.988625] 506 ret=80 copy=90 offset=0 len=90
> [ 301.988635] tun: 1124 0 -14 (null)
> [ 301.994762] 506 ret=80 copy=90 offset=0 len=90
> [ 301.994773] tun: 1124 0 -14 (null)
> [ 302.229962] 506 ret=332 copy=342 offset=0 len=342
> [ 302.229972] tun: 1124 0 -14 (null)
> [ 302.230621] 506 ret=332 copy=342 offset=0 len=342
> [ 302.230627] tun: 1124 0 -14 (null)
> [ 302.239065] 506 ret=332 copy=342 offset=0 len=342
> [ 302.239071] tun: 1124 0 -14 (null)
>
> It's returning 10 bytes less than the expected... ideas?
Could you print vnet_hdr_sz and sizeof(gso) right after that
copy_from_iter(&gso, ...)?
^ permalink raw reply [flat|nested] 12+ messages in thread* Re: tun issue after e0b46d0ee9c: tun: Use iovec iterators
2014-11-28 20:37 ` Al Viro
@ 2014-11-28 22:10 ` Marcelo Ricardo Leitner
2014-11-28 22:35 ` Al Viro
0 siblings, 1 reply; 12+ messages in thread
From: Marcelo Ricardo Leitner @ 2014-11-28 22:10 UTC (permalink / raw)
To: Al Viro; +Cc: herbert, netdev
On 28-11-2014 18:37, Al Viro wrote:
> On Fri, Nov 28, 2014 at 05:25:27PM -0200, Marcelo Ricardo Leitner wrote:
>> Hi,
>>
>> I saw there are tun updates on Dave's queue but none seemed to handle this.
>>
>> I can't use current net-next
>> (799d2fff1858004526ad75d66a5dd8a5cce6ad40) on a kvm hypervisor
>> because tun got clogged somehow. Bisected down to:
>
> Umm... In host, presumably?
>
Exactly
>> And net/core/datagram.c, skb_copy_datagram_from_iter():
>> if (copy > 0) {
>> int ret;
>> if (copy > len)
>> copy = len;
>> ret = copy_from_iter(skb->data + offset, copy, from);
>> if (ret != copy) {
>> pr_err("%d ret=%d copy=%d offset=%d
>> len=%d\n", __LINE__, ret, copy, offset, len);
>> goto fault;
>> }
>>
>>
>> I get, for tun interfaces:
>> [ 75.435552] 506 ret=80 copy=90 offset=0 len=90
>> [ 75.435563] tun: 1124 0 -14 (null)
>> [ 75.499528] 506 ret=80 copy=90 offset=0 len=90
>> [ 75.499540] tun: 1124 0 -14 (null)
>>
>> These were 1 drop on 1 interface each
>>
>> And for tap interfaces:
>> [ 301.982639] 506 ret=80 copy=90 offset=0 len=90
>> [ 301.982649] tun: 1124 0 -14 (null)
>> [ 301.988625] 506 ret=80 copy=90 offset=0 len=90
>> [ 301.988635] tun: 1124 0 -14 (null)
>> [ 301.994762] 506 ret=80 copy=90 offset=0 len=90
>> [ 301.994773] tun: 1124 0 -14 (null)
>> [ 302.229962] 506 ret=332 copy=342 offset=0 len=342
>> [ 302.229972] tun: 1124 0 -14 (null)
>> [ 302.230621] 506 ret=332 copy=342 offset=0 len=342
>> [ 302.230627] tun: 1124 0 -14 (null)
>> [ 302.239065] 506 ret=332 copy=342 offset=0 len=342
>> [ 302.239071] tun: 1124 0 -14 (null)
>>
>> It's returning 10 bytes less than the expected... ideas?
>
> Could you print vnet_hdr_sz and sizeof(gso) right after that
> copy_from_iter(&gso, ...)?
Did a:
else {
err = skb_copy_datagram_from_iter(skb, 0, from, len);
+ pr_err("vnet_hdr_sz=%d sizeof(gso)=%lu\n", tun->vnet_hdr_sz,
sizeof(gso));
if (!err && msg_control) {
Got, for tun:
[ 50.514165] tun: vnet_hdr_sz=12 sizeof(gso)=10
for tap:
[ 82.911840] tun: vnet_hdr_sz=10 sizeof(gso)=10
other values were just as before.
Marcelo
^ permalink raw reply [flat|nested] 12+ messages in thread* Re: tun issue after e0b46d0ee9c: tun: Use iovec iterators
2014-11-28 22:10 ` Marcelo Ricardo Leitner
@ 2014-11-28 22:35 ` Al Viro
2014-11-29 4:49 ` Marcelo Ricardo Leitner
0 siblings, 1 reply; 12+ messages in thread
From: Al Viro @ 2014-11-28 22:35 UTC (permalink / raw)
To: Marcelo Ricardo Leitner; +Cc: herbert, netdev
On Fri, Nov 28, 2014 at 08:10:03PM -0200, Marcelo Ricardo Leitner wrote:
> >Could you print vnet_hdr_sz and sizeof(gso) right after that
> >copy_from_iter(&gso, ...)?
>
> Did a:
> else {
> err = skb_copy_datagram_from_iter(skb, 0, from, len);
> + pr_err("vnet_hdr_sz=%d sizeof(gso)=%lu\n",
> tun->vnet_hdr_sz, sizeof(gso));
> if (!err && msg_control) {
>
> Got, for tun:
> [ 50.514165] tun: vnet_hdr_sz=12 sizeof(gso)=10
>
> for tap:
> [ 82.911840] tun: vnet_hdr_sz=10 sizeof(gso)=10
>
> other values were just as before.
Hmm... Do you have
commit 8c847d254146d32c86574a1b16923ff91bb784dd
Author: Jason Wang <jasowang@redhat.com>
Date: Thu Nov 13 16:54:14 2014 +0800
tun: fix issues of iovec iterators using in tun_put_user()
in your tree?
^ permalink raw reply [flat|nested] 12+ messages in thread* Re: tun issue after e0b46d0ee9c: tun: Use iovec iterators
2014-11-28 22:35 ` Al Viro
@ 2014-11-29 4:49 ` Marcelo Ricardo Leitner
0 siblings, 0 replies; 12+ messages in thread
From: Marcelo Ricardo Leitner @ 2014-11-29 4:49 UTC (permalink / raw)
To: Al Viro; +Cc: herbert, netdev
On 28-11-2014 20:35, Al Viro wrote:
> On Fri, Nov 28, 2014 at 08:10:03PM -0200, Marcelo Ricardo Leitner wrote:
>>> Could you print vnet_hdr_sz and sizeof(gso) right after that
>>> copy_from_iter(&gso, ...)?
>>
>> Did a:
>> else {
>> err = skb_copy_datagram_from_iter(skb, 0, from, len);
>> + pr_err("vnet_hdr_sz=%d sizeof(gso)=%lu\n",
>> tun->vnet_hdr_sz, sizeof(gso));
>> if (!err && msg_control) {
>>
>> Got, for tun:
>> [ 50.514165] tun: vnet_hdr_sz=12 sizeof(gso)=10
>>
>> for tap:
>> [ 82.911840] tun: vnet_hdr_sz=10 sizeof(gso)=10
>>
>> other values were just as before.
>
> Hmm... Do you have
> commit 8c847d254146d32c86574a1b16923ff91bb784dd
> Author: Jason Wang <jasowang@redhat.com>
> Date: Thu Nov 13 16:54:14 2014 +0800
>
> tun: fix issues of iovec iterators using in tun_put_user()
> in your tree?
>
Yes I have. I'm using based on net-next's
799d2fff1858004526ad75d66a5dd8a5cce6ad40.
Marcelo
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: tun issue after e0b46d0ee9c: tun: Use iovec iterators
2014-11-28 19:25 tun issue after e0b46d0ee9c: tun: Use iovec iterators Marcelo Ricardo Leitner
2014-11-28 20:37 ` Al Viro
@ 2014-11-28 23:59 ` Herbert Xu
2014-11-29 5:08 ` Marcelo Ricardo Leitner
2014-11-30 10:03 ` Herbert Xu
1 sibling, 2 replies; 12+ messages in thread
From: Herbert Xu @ 2014-11-28 23:59 UTC (permalink / raw)
To: Marcelo Ricardo Leitner; +Cc: netdev
On Fri, Nov 28, 2014 at 05:25:27PM -0200, Marcelo Ricardo Leitner wrote:
>
> I saw there are tun updates on Dave's queue but none seemed to handle this.
>
> I can't use current net-next
> (799d2fff1858004526ad75d66a5dd8a5cce6ad40) on a kvm hypervisor
> because tun got clogged somehow. Bisected down to:
>
> commit e0b46d0ee9c240c7430a47e9b0365674d4a04522
> Author: Herbert Xu <herbert@gondor.apana.org.au>
> Date: Fri Nov 7 21:22:23 2014 +0800
Does this patch help?
-- >8 --
Subject: tun: Fix GSO meta-data handling in tun_get_user
When we write the GSO meta-data in tun_get_user we end up advancing
the IO vector twice, thus exhausting the user buffer before we can
finish writing the packet.
Fixes: f5ff53b4d97c ("{macvtap,tun}_get_user(): switch to iov_iter")
Reported-by: Marcelo Ricardo Leitner <mleitner@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 4b743c6..9357871 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1052,7 +1052,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
if (gso.hdr_len > len)
return -EINVAL;
- iov_iter_advance(from, tun->vnet_hdr_sz);
+ iov_iter_advance(iter, tun->vnet_hdr_sz - sizeof(gso));
}
if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
Cheers,
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
^ permalink raw reply related [flat|nested] 12+ messages in thread* Re: tun issue after e0b46d0ee9c: tun: Use iovec iterators
2014-11-28 23:59 ` Herbert Xu
@ 2014-11-29 5:08 ` Marcelo Ricardo Leitner
2014-11-30 8:21 ` Herbert Xu
2014-11-30 10:03 ` Herbert Xu
1 sibling, 1 reply; 12+ messages in thread
From: Marcelo Ricardo Leitner @ 2014-11-29 5:08 UTC (permalink / raw)
To: Herbert Xu; +Cc: netdev
On 28-11-2014 21:59, Herbert Xu wrote:
> On Fri, Nov 28, 2014 at 05:25:27PM -0200, Marcelo Ricardo Leitner wrote:
>>
>> I saw there are tun updates on Dave's queue but none seemed to handle this.
>>
>> I can't use current net-next
>> (799d2fff1858004526ad75d66a5dd8a5cce6ad40) on a kvm hypervisor
>> because tun got clogged somehow. Bisected down to:
>>
>> commit e0b46d0ee9c240c7430a47e9b0365674d4a04522
>> Author: Herbert Xu <herbert@gondor.apana.org.au>
>> Date: Fri Nov 7 21:22:23 2014 +0800
>
> Does this patch help?
Yay, it does! Works for me, thanks Herbert.
I didn't test performance, but dhcp could get through.
Are you sure about the Fixes tag? Because bisect really pointed to e0b46d0ee9c.
Cheers,
Marcelo
> -- >8 --
> Subject: tun: Fix GSO meta-data handling in tun_get_user
>
> When we write the GSO meta-data in tun_get_user we end up advancing
> the IO vector twice, thus exhausting the user buffer before we can
> finish writing the packet.
>
> Fixes: f5ff53b4d97c ("{macvtap,tun}_get_user(): switch to iov_iter")
> Reported-by: Marcelo Ricardo Leitner <mleitner@redhat.com>
> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
>
> diff --git a/drivers/net/tun.c b/drivers/net/tun.c
> index 4b743c6..9357871 100644
> --- a/drivers/net/tun.c
> +++ b/drivers/net/tun.c
> @@ -1052,7 +1052,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
>
> if (gso.hdr_len > len)
> return -EINVAL;
> - iov_iter_advance(from, tun->vnet_hdr_sz);
> + iov_iter_advance(iter, tun->vnet_hdr_sz - sizeof(gso));
> }
>
> if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
>
> Cheers,
>
^ permalink raw reply [flat|nested] 12+ messages in thread* Re: tun issue after e0b46d0ee9c: tun: Use iovec iterators
2014-11-29 5:08 ` Marcelo Ricardo Leitner
@ 2014-11-30 8:21 ` Herbert Xu
2014-12-01 13:05 ` Marcelo Ricardo Leitner
0 siblings, 1 reply; 12+ messages in thread
From: Herbert Xu @ 2014-11-30 8:21 UTC (permalink / raw)
To: Marcelo Ricardo Leitner; +Cc: netdev
On Sat, Nov 29, 2014 at 03:08:09AM -0200, Marcelo Ricardo Leitner wrote:
> On 28-11-2014 21:59, Herbert Xu wrote:
> >On Fri, Nov 28, 2014 at 05:25:27PM -0200, Marcelo Ricardo Leitner wrote:
> >>
> >>I saw there are tun updates on Dave's queue but none seemed to handle this.
> >>
> >>I can't use current net-next
> >>(799d2fff1858004526ad75d66a5dd8a5cce6ad40) on a kvm hypervisor
> >>because tun got clogged somehow. Bisected down to:
> >>
> >>commit e0b46d0ee9c240c7430a47e9b0365674d4a04522
> >>Author: Herbert Xu <herbert@gondor.apana.org.au>
> >>Date: Fri Nov 7 21:22:23 2014 +0800
> >
> >Does this patch help?
>
> Yay, it does! Works for me, thanks Herbert.
> I didn't test performance, but dhcp could get through.
>
> Are you sure about the Fixes tag? Because bisect really pointed to e0b46d0ee9c.
Well according to your report you were having problems with
tun_get_user. The bug I introduced was in tun_put_user and has
already been fixed by Jason Wang.
Cheers,
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: tun issue after e0b46d0ee9c: tun: Use iovec iterators
2014-11-30 8:21 ` Herbert Xu
@ 2014-12-01 13:05 ` Marcelo Ricardo Leitner
0 siblings, 0 replies; 12+ messages in thread
From: Marcelo Ricardo Leitner @ 2014-12-01 13:05 UTC (permalink / raw)
To: Herbert Xu; +Cc: netdev
On 30-11-2014 06:21, Herbert Xu wrote:
> On Sat, Nov 29, 2014 at 03:08:09AM -0200, Marcelo Ricardo Leitner wrote:
>> On 28-11-2014 21:59, Herbert Xu wrote:
>>> On Fri, Nov 28, 2014 at 05:25:27PM -0200, Marcelo Ricardo Leitner wrote:
>>>>
>>>> I saw there are tun updates on Dave's queue but none seemed to handle this.
>>>>
>>>> I can't use current net-next
>>>> (799d2fff1858004526ad75d66a5dd8a5cce6ad40) on a kvm hypervisor
>>>> because tun got clogged somehow. Bisected down to:
>>>>
>>>> commit e0b46d0ee9c240c7430a47e9b0365674d4a04522
>>>> Author: Herbert Xu <herbert@gondor.apana.org.au>
>>>> Date: Fri Nov 7 21:22:23 2014 +0800
>>>
>>> Does this patch help?
>>
>> Yay, it does! Works for me, thanks Herbert.
>> I didn't test performance, but dhcp could get through.
>>
>> Are you sure about the Fixes tag? Because bisect really pointed to e0b46d0ee9c.
>
> Well according to your report you were having problems with
> tun_get_user. The bug I introduced was in tun_put_user and has
> already been fixed by Jason Wang.
Ahh yes, ok. Thanks
Cheers,
Marcelo
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: tun issue after e0b46d0ee9c: tun: Use iovec iterators
2014-11-28 23:59 ` Herbert Xu
2014-11-29 5:08 ` Marcelo Ricardo Leitner
@ 2014-11-30 10:03 ` Herbert Xu
2014-12-01 5:33 ` Jason Wang
2014-12-03 4:54 ` David Miller
1 sibling, 2 replies; 12+ messages in thread
From: Herbert Xu @ 2014-11-30 10:03 UTC (permalink / raw)
To: Marcelo Ricardo Leitner; +Cc: netdev
On Sat, Nov 29, 2014 at 07:59:35AM +0800, Herbert Xu wrote:
> On Fri, Nov 28, 2014 at 05:25:27PM -0200, Marcelo Ricardo Leitner wrote:
> >
> > I saw there are tun updates on Dave's queue but none seemed to handle this.
> >
> > I can't use current net-next
> > (799d2fff1858004526ad75d66a5dd8a5cce6ad40) on a kvm hypervisor
> > because tun got clogged somehow. Bisected down to:
> >
> > commit e0b46d0ee9c240c7430a47e9b0365674d4a04522
> > Author: Herbert Xu <herbert@gondor.apana.org.au>
> > Date: Fri Nov 7 21:22:23 2014 +0800
>
> Does this patch help?
Oops, there was an embarrassing typo in the patch which causes
it to not even build. Here is the corrected version.
-- >8 --
Subject: tun: Fix GSO meta-data handling in tun_get_user
When we write the GSO meta-data in tun_get_user we end up advancing
the IO vector twice, thus exhausting the user buffer before we can
finish writing the packet.
Fixes: f5ff53b4d97c ("{macvtap,tun}_get_user(): switch to iov_iter")
Reported-by: Marcelo Ricardo Leitner <mleitner@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 4b743c6..6d44da1 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1052,7 +1052,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
if (gso.hdr_len > len)
return -EINVAL;
- iov_iter_advance(from, tun->vnet_hdr_sz);
+ iov_iter_advance(from, tun->vnet_hdr_sz - sizeof(gso));
}
if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
Thanks,
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
^ permalink raw reply related [flat|nested] 12+ messages in thread* Re: tun issue after e0b46d0ee9c: tun: Use iovec iterators
2014-11-30 10:03 ` Herbert Xu
@ 2014-12-01 5:33 ` Jason Wang
2014-12-03 4:54 ` David Miller
1 sibling, 0 replies; 12+ messages in thread
From: Jason Wang @ 2014-12-01 5:33 UTC (permalink / raw)
To: Herbert Xu; +Cc: Marcelo Ricardo Leitner, netdev
On Sun, Nov 30, 2014 at 6:03 PM, Herbert Xu
<herbert@gondor.apana.org.au> wrote:
> On Sat, Nov 29, 2014 at 07:59:35AM +0800, Herbert Xu wrote:
>> On Fri, Nov 28, 2014 at 05:25:27PM -0200, Marcelo Ricardo Leitner
>> wrote:
>> >
>> > I saw there are tun updates on Dave's queue but none seemed to
>> handle this.
>> >
>> > I can't use current net-next
>> > (799d2fff1858004526ad75d66a5dd8a5cce6ad40) on a kvm hypervisor
>> > because tun got clogged somehow. Bisected down to:
>> >
>> > commit e0b46d0ee9c240c7430a47e9b0365674d4a04522
>> > Author: Herbert Xu <herbert@gondor.apana.org.au>
>> > Date: Fri Nov 7 21:22:23 2014 +0800
>>
>> Does this patch help?
>
> Oops, there was an embarrassing typo in the patch which causes
> it to not even build. Here is the corrected version.
>
> -- >8 --
> Subject: tun: Fix GSO meta-data handling in tun_get_user
>
> When we write the GSO meta-data in tun_get_user we end up advancing
> the IO vector twice, thus exhausting the user buffer before we can
> finish writing the packet.
>
> Fixes: f5ff53b4d97c ("{macvtap,tun}_get_user(): switch to iov_iter")
> Reported-by: Marcelo Ricardo Leitner <mleitner@redhat.com>
> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
>
> diff --git a/drivers/net/tun.c b/drivers/net/tun.c
> index 4b743c6..6d44da1 100644
> --- a/drivers/net/tun.c
> +++ b/drivers/net/tun.c
> @@ -1052,7 +1052,7 @@ static ssize_t tun_get_user(struct tun_struct
> *tun, struct tun_file *tfile,
>
> if (gso.hdr_len > len)
> return -EINVAL;
> - iov_iter_advance(from, tun->vnet_hdr_sz);
> + iov_iter_advance(from, tun->vnet_hdr_sz - sizeof(gso));
> }
>
> if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
>
Acked-by: Jason Wang <jasowang@redhat.com>
^ permalink raw reply [flat|nested] 12+ messages in thread* Re: tun issue after e0b46d0ee9c: tun: Use iovec iterators
2014-11-30 10:03 ` Herbert Xu
2014-12-01 5:33 ` Jason Wang
@ 2014-12-03 4:54 ` David Miller
1 sibling, 0 replies; 12+ messages in thread
From: David Miller @ 2014-12-03 4:54 UTC (permalink / raw)
To: herbert; +Cc: mleitner, netdev
From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Sun, 30 Nov 2014 18:03:31 +0800
> On Sat, Nov 29, 2014 at 07:59:35AM +0800, Herbert Xu wrote:
>> On Fri, Nov 28, 2014 at 05:25:27PM -0200, Marcelo Ricardo Leitner wrote:
>> >
>> > I saw there are tun updates on Dave's queue but none seemed to handle this.
>> >
>> > I can't use current net-next
>> > (799d2fff1858004526ad75d66a5dd8a5cce6ad40) on a kvm hypervisor
>> > because tun got clogged somehow. Bisected down to:
>> >
>> > commit e0b46d0ee9c240c7430a47e9b0365674d4a04522
>> > Author: Herbert Xu <herbert@gondor.apana.org.au>
>> > Date: Fri Nov 7 21:22:23 2014 +0800
>>
>> Does this patch help?
>
> Oops, there was an embarrassing typo in the patch which causes
> it to not even build. Here is the corrected version.
>
> -- >8 --
> Subject: tun: Fix GSO meta-data handling in tun_get_user
>
> When we write the GSO meta-data in tun_get_user we end up advancing
> the IO vector twice, thus exhausting the user buffer before we can
> finish writing the packet.
>
> Fixes: f5ff53b4d97c ("{macvtap,tun}_get_user(): switch to iov_iter")
> Reported-by: Marcelo Ricardo Leitner <mleitner@redhat.com>
> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Applied, thanks.
^ permalink raw reply [flat|nested] 12+ messages in thread
end of thread, other threads:[~2014-12-03 4:50 UTC | newest]
Thread overview: 12+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2014-11-28 19:25 tun issue after e0b46d0ee9c: tun: Use iovec iterators Marcelo Ricardo Leitner
2014-11-28 20:37 ` Al Viro
2014-11-28 22:10 ` Marcelo Ricardo Leitner
2014-11-28 22:35 ` Al Viro
2014-11-29 4:49 ` Marcelo Ricardo Leitner
2014-11-28 23:59 ` Herbert Xu
2014-11-29 5:08 ` Marcelo Ricardo Leitner
2014-11-30 8:21 ` Herbert Xu
2014-12-01 13:05 ` Marcelo Ricardo Leitner
2014-11-30 10:03 ` Herbert Xu
2014-12-01 5:33 ` Jason Wang
2014-12-03 4:54 ` David Miller
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