thr3ads.net - Linux Virtualization - [PATCH] vhost_net: clear msg.control for non-zerocopy case during tx [Jun 2013]

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Jason Wang

2013-Jun-05 07:40 UTC

[PATCH] vhost_net: clear msg.control for non-zerocopy case during tx

When we decide not use zero-copy, msg.control should be set to NULL otherwise
macvtap/tap may set zerocopy callbacks which may decrease the kref of ubufs
wrongly.

Bug were introduced by commit cedb9bdce099206290a2bdd02ce47a7b253b6a84
(vhost-net: skip head management if no outstanding).

This solves the following warnings:

WARNING: at include/linux/kref.h:47 handle_tx+0x477/0x4b0 [vhost_net]()
Modules linked in: vhost_net macvtap macvlan tun nfsd exportfs bridge stp llc
openvswitch kvm_amd kvm bnx2 megaraid_sas [last unloaded: tun]
CPU: 5 PID: 8670 Comm: vhost-8668 Not tainted 3.10.0-rc2+ #1566
Hardware name: Dell Inc. PowerEdge R715/00XHKG, BIOS 1.5.2 04/19/2011
ffffffffa0198323 ffff88007c9ebd08 ffffffff81796b73 ffff88007c9ebd48
ffffffff8103d66b 000000007b773e20 ffff8800779f0000 ffff8800779f43f0
ffff8800779f8418 000000000000015c 0000000000000062 ffff88007c9ebd58
Call Trace:
[<ffffffff81796b73>] dump_stack+0x19/0x1e
[<ffffffff8103d66b>] warn_slowpath_common+0x6b/0xa0
[<ffffffff8103d6b5>] warn_slowpath_null+0x15/0x20
[<ffffffffa0197627>] handle_tx+0x477/0x4b0 [vhost_net]
[<ffffffffa0197690>] handle_tx_kick+0x10/0x20 [vhost_net]
[<ffffffffa019541e>] vhost_worker+0xfe/0x1a0 [vhost_net]
[<ffffffffa0195320>] ? vhost_attach_cgroups_work+0x30/0x30 [vhost_net]
[<ffffffffa0195320>] ? vhost_attach_cgroups_work+0x30/0x30 [vhost_net]
[<ffffffff81061f46>] kthread+0xc6/0xd0
[<ffffffff81061e80>] ? kthread_freezable_should_stop+0x70/0x70
[<ffffffff817a1aec>] ret_from_fork+0x7c/0xb0
[<ffffffff81061e80>] ? kthread_freezable_should_stop+0x70/0x70

Signed-off-by: Jason Wang <jasowang at redhat.com>
---
 drivers/vhost/net.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 2b51e23..b07d96b 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -436,7 +436,8 @@ static void handle_tx(struct vhost_net *net)
 				kref_get(&ubufs->kref);
 			}
 			nvq->upend_idx = (nvq->upend_idx + 1) % UIO_MAXIOV;
-		}
+		} else
+			msg.msg_control = NULL;
 		/* TODO: Check specific error and bomb out unless ENOBUFS? */
 		err = sock->ops->sendmsg(NULL, sock, &msg, len);
 		if (unlikely(err < 0)) {
-- 
1.7.1

Michael S. Tsirkin

2013-Jun-05 09:02 UTC

head link

[PATCH] vhost_net: clear msg.control for non-zerocopy case during tx

On Wed, Jun 05, 2013 at 03:40:46PM +0800, Jason Wang
wrote:> When we decide not use zero-copy, msg.control should be set to NULL
otherwise
> macvtap/tap may set zerocopy callbacks which may decrease the kref of ubufs
> wrongly.
> 
> Bug were introduced by commit cedb9bdce099206290a2bdd02ce47a7b253b6a84
> (vhost-net: skip head management if no outstanding).
> 
> This solves the following warnings:
> 
> WARNING: at include/linux/kref.h:47 handle_tx+0x477/0x4b0 [vhost_net]()
> Modules linked in: vhost_net macvtap macvlan tun nfsd exportfs bridge stp
llc openvswitch kvm_amd kvm bnx2 megaraid_sas [last unloaded: tun]
> CPU: 5 PID: 8670 Comm: vhost-8668 Not tainted 3.10.0-rc2+ #1566
> Hardware name: Dell Inc. PowerEdge R715/00XHKG, BIOS 1.5.2 04/19/2011
> ffffffffa0198323 ffff88007c9ebd08 ffffffff81796b73 ffff88007c9ebd48
> ffffffff8103d66b 000000007b773e20 ffff8800779f0000 ffff8800779f43f0
> ffff8800779f8418 000000000000015c 0000000000000062 ffff88007c9ebd58
> Call Trace:
> [<ffffffff81796b73>] dump_stack+0x19/0x1e
> [<ffffffff8103d66b>] warn_slowpath_common+0x6b/0xa0
> [<ffffffff8103d6b5>] warn_slowpath_null+0x15/0x20
> [<ffffffffa0197627>] handle_tx+0x477/0x4b0 [vhost_net]
> [<ffffffffa0197690>] handle_tx_kick+0x10/0x20 [vhost_net]
> [<ffffffffa019541e>] vhost_worker+0xfe/0x1a0 [vhost_net]
> [<ffffffffa0195320>] ? vhost_attach_cgroups_work+0x30/0x30
[vhost_net]
> [<ffffffffa0195320>] ? vhost_attach_cgroups_work+0x30/0x30
[vhost_net]
> [<ffffffff81061f46>] kthread+0xc6/0xd0
> [<ffffffff81061e80>] ? kthread_freezable_should_stop+0x70/0x70
> [<ffffffff817a1aec>] ret_from_fork+0x7c/0xb0
> [<ffffffff81061e80>] ? kthread_freezable_should_stop+0x70/0x70
> 
> Signed-off-by: Jason Wang <jasowang at redhat.com>
Good catch.

Acked-by: Michael S. Tsirkin <mst at redhat.com>

This needs to go into stable as well.
> ---
>  drivers/vhost/net.c |    3 ++-
>  1 files changed, 2 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
> index 2b51e23..b07d96b 100644
> --- a/drivers/vhost/net.c
> +++ b/drivers/vhost/net.c
> @@ -436,7 +436,8 @@ static void handle_tx(struct vhost_net *net)
>  				kref_get(&ubufs->kref);
>  			}
>  			nvq->upend_idx = (nvq->upend_idx + 1) % UIO_MAXIOV;
> -		}
> +		} else
> +			msg.msg_control = NULL;
>  		/* TODO: Check specific error and bomb out unless ENOBUFS? */
>  		err = sock->ops->sendmsg(NULL, sock, &msg, len);
>  		if (unlikely(err < 0)) {
> -- 
> 1.7.1

Sergei Shtylyov

2013-Jun-05 13:44 UTC

head link

[PATCH] vhost_net: clear msg.control for non-zerocopy case during tx

Hello.

On 05-06-2013 11:40, Jason Wang wrote:
> When we decide not use zero-copy, msg.control should be set to NULL
otherwise
> macvtap/tap may set zerocopy callbacks which may decrease the kref of ubufs
> wrongly.
> Bug were introduced by commit cedb9bdce099206290a2bdd02ce47a7b253b6a84
> (vhost-net: skip head management if no outstanding).
> This solves the following warnings:
> WARNING: at include/linux/kref.h:47 handle_tx+0x477/0x4b0 [vhost_net]()
> Modules linked in: vhost_net macvtap macvlan tun nfsd exportfs bridge stp
llc openvswitch kvm_amd kvm bnx2 megaraid_sas [last unloaded: tun]
> CPU: 5 PID: 8670 Comm: vhost-8668 Not tainted 3.10.0-rc2+ #1566
> Hardware name: Dell Inc. PowerEdge R715/00XHKG, BIOS 1.5.2 04/19/2011
> ffffffffa0198323 ffff88007c9ebd08 ffffffff81796b73 ffff88007c9ebd48
> ffffffff8103d66b 000000007b773e20 ffff8800779f0000 ffff8800779f43f0
> ffff8800779f8418 000000000000015c 0000000000000062 ffff88007c9ebd58
> Call Trace:
> [<ffffffff81796b73>] dump_stack+0x19/0x1e
> [<ffffffff8103d66b>] warn_slowpath_common+0x6b/0xa0
> [<ffffffff8103d6b5>] warn_slowpath_null+0x15/0x20
> [<ffffffffa0197627>] handle_tx+0x477/0x4b0 [vhost_net]
> [<ffffffffa0197690>] handle_tx_kick+0x10/0x20 [vhost_net]
> [<ffffffffa019541e>] vhost_worker+0xfe/0x1a0 [vhost_net]
> [<ffffffffa0195320>] ? vhost_attach_cgroups_work+0x30/0x30
[vhost_net]
> [<ffffffffa0195320>] ? vhost_attach_cgroups_work+0x30/0x30
[vhost_net]
> [<ffffffff81061f46>] kthread+0xc6/0xd0
> [<ffffffff81061e80>] ? kthread_freezable_should_stop+0x70/0x70
> [<ffffffff817a1aec>] ret_from_fork+0x7c/0xb0
> [<ffffffff81061e80>] ? kthread_freezable_should_stop+0x70/0x70
> Signed-off-by: Jason Wang <jasowang at redhat.com>
> ---
>   drivers/vhost/net.c |    3 ++-
>   1 files changed, 2 insertions(+), 1 deletions(-)
> diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
> index 2b51e23..b07d96b 100644
> --- a/drivers/vhost/net.c
> +++ b/drivers/vhost/net.c
> @@ -436,7 +436,8 @@ static void handle_tx(struct vhost_net *net)
>   				kref_get(&ubufs->kref);
>   			}
>   			nvq->upend_idx = (nvq->upend_idx + 1) % UIO_MAXIOV;
> -		}
> +		} else
    You have to use {} on the *else* branch if you have it of the *if* 
branch (and vice versa), according to Documentation/CodingStyle.
> +			msg.msg_control = NULL;
WBR, Sergei

Jason Wang

2013-Jun-06 03:27 UTC

head link

[PATCH] vhost_net: clear msg.control for non-zerocopy case during tx

On 06/05/2013 09:44 PM, Sergei Shtylyov wrote:> Hello.
>
> On 05-06-2013 11:40, Jason Wang wrote:
>
>> When we decide not use zero-copy, msg.control should be set to NULL
>> otherwise
>> macvtap/tap may set zerocopy callbacks which may decrease the kref of
>> ubufs
>> wrongly.
>
>> Bug were introduced by commit cedb9bdce099206290a2bdd02ce47a7b253b6a84
>> (vhost-net: skip head management if no outstanding).
>
>> This solves the following warnings:
>
>> WARNING: at include/linux/kref.h:47 handle_tx+0x477/0x4b0 [vhost_net]()
>> Modules linked in: vhost_net macvtap macvlan tun nfsd exportfs bridge
>> stp llc openvswitch kvm_amd kvm bnx2 megaraid_sas [last unloaded: tun]
>> CPU: 5 PID: 8670 Comm: vhost-8668 Not tainted 3.10.0-rc2+ #1566
>> Hardware name: Dell Inc. PowerEdge R715/00XHKG, BIOS 1.5.2 04/19/2011
>> ffffffffa0198323 ffff88007c9ebd08 ffffffff81796b73 ffff88007c9ebd48
>> ffffffff8103d66b 000000007b773e20 ffff8800779f0000 ffff8800779f43f0
>> ffff8800779f8418 000000000000015c 0000000000000062 ffff88007c9ebd58
>> Call Trace:
>> [<ffffffff81796b73>] dump_stack+0x19/0x1e
>> [<ffffffff8103d66b>] warn_slowpath_common+0x6b/0xa0
>> [<ffffffff8103d6b5>] warn_slowpath_null+0x15/0x20
>> [<ffffffffa0197627>] handle_tx+0x477/0x4b0 [vhost_net]
>> [<ffffffffa0197690>] handle_tx_kick+0x10/0x20 [vhost_net]
>> [<ffffffffa019541e>] vhost_worker+0xfe/0x1a0 [vhost_net]
>> [<ffffffffa0195320>] ? vhost_attach_cgroups_work+0x30/0x30
[vhost_net]
>> [<ffffffffa0195320>] ? vhost_attach_cgroups_work+0x30/0x30
[vhost_net]
>> [<ffffffff81061f46>] kthread+0xc6/0xd0
>> [<ffffffff81061e80>] ? kthread_freezable_should_stop+0x70/0x70
>> [<ffffffff817a1aec>] ret_from_fork+0x7c/0xb0
>> [<ffffffff81061e80>] ? kthread_freezable_should_stop+0x70/0x70
>
>> Signed-off-by: Jason Wang <jasowang at redhat.com>
>> ---
>>   drivers/vhost/net.c |    3 ++-
>>   1 files changed, 2 insertions(+), 1 deletions(-)
>
>> diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
>> index 2b51e23..b07d96b 100644
>> --- a/drivers/vhost/net.c
>> +++ b/drivers/vhost/net.c
>> @@ -436,7 +436,8 @@ static void handle_tx(struct vhost_net *net)
>>                   kref_get(&ubufs->kref);
>>               }
>>               nvq->upend_idx = (nvq->upend_idx + 1) % UIO_MAXIOV;
>> -        }
>> +        } else
>
>    You have to use {} on the *else* branch if you have it of the *if*
> branch (and vice versa), according to Documentation/CodingStyle.
checkpatch.pl didn't complain this, will send v2.

Thanks>
>> +            msg.msg_control = NULL;
>
> WBR, Sergei
>
> -- 
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David Miller

2013-Jun-10 21:32 UTC

head link

[PATCH] vhost_net: clear msg.control for non-zerocopy case during tx

From: "Michael S. Tsirkin" <mst at redhat.com>
Date: Wed, 5 Jun 2013 12:02:52 +0300
> On Wed, Jun 05, 2013 at 03:40:46PM +0800, Jason Wang wrote:
>> When we decide not use zero-copy, msg.control should be set to NULL
otherwise
>> macvtap/tap may set zerocopy callbacks which may decrease the kref of
ubufs
>> wrongly.
>> 
>> Bug were introduced by commit cedb9bdce099206290a2bdd02ce47a7b253b6a84
>> (vhost-net: skip head management if no outstanding).
>> 
>> This solves the following warnings:
>> 
>> WARNING: at include/linux/kref.h:47 handle_tx+0x477/0x4b0 [vhost_net]()
>> Modules linked in: vhost_net macvtap macvlan tun nfsd exportfs bridge
stp llc openvswitch kvm_amd kvm bnx2 megaraid_sas [last unloaded: tun]
>> CPU: 5 PID: 8670 Comm: vhost-8668 Not tainted 3.10.0-rc2+ #1566
>> Hardware name: Dell Inc. PowerEdge R715/00XHKG, BIOS 1.5.2 04/19/2011
>> ffffffffa0198323 ffff88007c9ebd08 ffffffff81796b73 ffff88007c9ebd48
>> ffffffff8103d66b 000000007b773e20 ffff8800779f0000 ffff8800779f43f0
>> ffff8800779f8418 000000000000015c 0000000000000062 ffff88007c9ebd58
>> Call Trace:
>> [<ffffffff81796b73>] dump_stack+0x19/0x1e
>> [<ffffffff8103d66b>] warn_slowpath_common+0x6b/0xa0
>> [<ffffffff8103d6b5>] warn_slowpath_null+0x15/0x20
>> [<ffffffffa0197627>] handle_tx+0x477/0x4b0 [vhost_net]
>> [<ffffffffa0197690>] handle_tx_kick+0x10/0x20 [vhost_net]
>> [<ffffffffa019541e>] vhost_worker+0xfe/0x1a0 [vhost_net]
>> [<ffffffffa0195320>] ? vhost_attach_cgroups_work+0x30/0x30
[vhost_net]
>> [<ffffffffa0195320>] ? vhost_attach_cgroups_work+0x30/0x30
[vhost_net]
>> [<ffffffff81061f46>] kthread+0xc6/0xd0
>> [<ffffffff81061e80>] ? kthread_freezable_should_stop+0x70/0x70
>> [<ffffffff817a1aec>] ret_from_fork+0x7c/0xb0
>> [<ffffffff81061e80>] ? kthread_freezable_should_stop+0x70/0x70
>> 
>> Signed-off-by: Jason Wang <jasowang at redhat.com>
> 
> Good catch.
> 
> Acked-by: Michael S. Tsirkin <mst at redhat.com>
> 
> This needs to go into stable as well.
Applied and queued up for -stable.

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