* [Patch net-next v2] netpoll: fix a rtnl lock assertion failure
@ 2013-01-14 10:24 Cong Wang
2013-01-14 10:32 ` Jiri Pirko
0 siblings, 1 reply; 3+ messages in thread
From: Cong Wang @ 2013-01-14 10:24 UTC (permalink / raw)
To: netdev; +Cc: Jiri Pirko, David S. Miller, Cong Wang
From: Cong Wang <amwang@redhat.com>
This patch fixes the following warning:
[ 72.013864] RTNL: assertion failed at net/core/dev.c (4955)
[ 72.017758] Pid: 668, comm: netpoll-prep-v6 Not tainted 3.8.0-rc1+ #474
[ 72.019582] Call Trace:
[ 72.020295] [<ffffffff8176653d>] netdev_master_upper_dev_get+0x35/0x58
[ 72.022545] [<ffffffff81784edd>] netpoll_setup+0x61/0x340
[ 72.024846] [<ffffffff815d837e>] store_enabled+0x82/0xc3
[ 72.027466] [<ffffffff815d7e51>] netconsole_target_attr_store+0x35/0x37
[ 72.029348] [<ffffffff811c3479>] configfs_write_file+0xe2/0x10c
[ 72.030959] [<ffffffff8115d239>] vfs_write+0xaf/0xf6
[ 72.032359] [<ffffffff81978a05>] ? sysret_check+0x22/0x5d
[ 72.033824] [<ffffffff8115d453>] sys_write+0x5c/0x84
[ 72.035328] [<ffffffff819789d9>] system_call_fastpath+0x16/0x1b
Just hold RCU read lock and call netdev_master_upper_dev_get_rcu(),
as suggested by Jiri.
Cc: Jiri Pirko <jiri@resnulli.us>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Cong Wang <amwang@redhat.com>
---
diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index 9f05067..6d56b57 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -1055,11 +1055,15 @@ int netpoll_setup(struct netpoll *np)
return -ENODEV;
}
- if (netdev_master_upper_dev_get(ndev)) {
+ rcu_read_lock();
+ /* We permit devices with VLAN attached to */
+ if (netdev_master_upper_dev_get_rcu(ndev)) {
+ rcu_read_unlock();
np_err(np, "%s is a slave device, aborting\n", np->dev_name);
err = -EBUSY;
goto put;
}
+ rcu_read_unlock();
if (!netif_running(ndev)) {
unsigned long atmost, atleast;
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [Patch net-next v2] netpoll: fix a rtnl lock assertion failure
2013-01-14 10:24 [Patch net-next v2] netpoll: fix a rtnl lock assertion failure Cong Wang
@ 2013-01-14 10:32 ` Jiri Pirko
2013-01-14 10:42 ` Cong Wang
0 siblings, 1 reply; 3+ messages in thread
From: Jiri Pirko @ 2013-01-14 10:32 UTC (permalink / raw)
To: Cong Wang; +Cc: netdev, David S. Miller
Mon, Jan 14, 2013 at 11:24:14AM CET, amwang@redhat.com wrote:
>From: Cong Wang <amwang@redhat.com>
>
>This patch fixes the following warning:
>
>[ 72.013864] RTNL: assertion failed at net/core/dev.c (4955)
>[ 72.017758] Pid: 668, comm: netpoll-prep-v6 Not tainted 3.8.0-rc1+ #474
>[ 72.019582] Call Trace:
>[ 72.020295] [<ffffffff8176653d>] netdev_master_upper_dev_get+0x35/0x58
>[ 72.022545] [<ffffffff81784edd>] netpoll_setup+0x61/0x340
>[ 72.024846] [<ffffffff815d837e>] store_enabled+0x82/0xc3
>[ 72.027466] [<ffffffff815d7e51>] netconsole_target_attr_store+0x35/0x37
>[ 72.029348] [<ffffffff811c3479>] configfs_write_file+0xe2/0x10c
>[ 72.030959] [<ffffffff8115d239>] vfs_write+0xaf/0xf6
>[ 72.032359] [<ffffffff81978a05>] ? sysret_check+0x22/0x5d
>[ 72.033824] [<ffffffff8115d453>] sys_write+0x5c/0x84
>[ 72.035328] [<ffffffff819789d9>] system_call_fastpath+0x16/0x1b
>
>Just hold RCU read lock and call netdev_master_upper_dev_get_rcu(),
>as suggested by Jiri.
>
>Cc: Jiri Pirko <jiri@resnulli.us>
>Cc: David S. Miller <davem@davemloft.net>
>Signed-off-by: Cong Wang <amwang@redhat.com>
>
>---
>diff --git a/net/core/netpoll.c b/net/core/netpoll.c
>index 9f05067..6d56b57 100644
>--- a/net/core/netpoll.c
>+++ b/net/core/netpoll.c
>@@ -1055,11 +1055,15 @@ int netpoll_setup(struct netpoll *np)
> return -ENODEV;
> }
>
>- if (netdev_master_upper_dev_get(ndev)) {
>+ rcu_read_lock();
>+ /* We permit devices with VLAN attached to */
I think that this comment might be misleading. Master upper is not set
not only for VLAN but for macvlan (and in future possibly for others) as well.
Apart from this, the patch looks good to me.
>+ if (netdev_master_upper_dev_get_rcu(ndev)) {
>+ rcu_read_unlock();
> np_err(np, "%s is a slave device, aborting\n", np->dev_name);
> err = -EBUSY;
> goto put;
> }
>+ rcu_read_unlock();
>
> if (!netif_running(ndev)) {
> unsigned long atmost, atleast;
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [Patch net-next v2] netpoll: fix a rtnl lock assertion failure
2013-01-14 10:32 ` Jiri Pirko
@ 2013-01-14 10:42 ` Cong Wang
0 siblings, 0 replies; 3+ messages in thread
From: Cong Wang @ 2013-01-14 10:42 UTC (permalink / raw)
To: Jiri Pirko; +Cc: netdev, David S. Miller
On Mon, 2013-01-14 at 11:32 +0100, Jiri Pirko wrote:
> Mon, Jan 14, 2013 at 11:24:14AM CET, amwang@redhat.com wrote:
> >From: Cong Wang <amwang@redhat.com>
> >
> >This patch fixes the following warning:
> >
> >[ 72.013864] RTNL: assertion failed at net/core/dev.c (4955)
> >[ 72.017758] Pid: 668, comm: netpoll-prep-v6 Not tainted 3.8.0-rc1+ #474
> >[ 72.019582] Call Trace:
> >[ 72.020295] [<ffffffff8176653d>] netdev_master_upper_dev_get+0x35/0x58
> >[ 72.022545] [<ffffffff81784edd>] netpoll_setup+0x61/0x340
> >[ 72.024846] [<ffffffff815d837e>] store_enabled+0x82/0xc3
> >[ 72.027466] [<ffffffff815d7e51>] netconsole_target_attr_store+0x35/0x37
> >[ 72.029348] [<ffffffff811c3479>] configfs_write_file+0xe2/0x10c
> >[ 72.030959] [<ffffffff8115d239>] vfs_write+0xaf/0xf6
> >[ 72.032359] [<ffffffff81978a05>] ? sysret_check+0x22/0x5d
> >[ 72.033824] [<ffffffff8115d453>] sys_write+0x5c/0x84
> >[ 72.035328] [<ffffffff819789d9>] system_call_fastpath+0x16/0x1b
> >
> >Just hold RCU read lock and call netdev_master_upper_dev_get_rcu(),
> >as suggested by Jiri.
> >
> >Cc: Jiri Pirko <jiri@resnulli.us>
> >Cc: David S. Miller <davem@davemloft.net>
> >Signed-off-by: Cong Wang <amwang@redhat.com>
> >
> >---
> >diff --git a/net/core/netpoll.c b/net/core/netpoll.c
> >index 9f05067..6d56b57 100644
> >--- a/net/core/netpoll.c
> >+++ b/net/core/netpoll.c
> >@@ -1055,11 +1055,15 @@ int netpoll_setup(struct netpoll *np)
> > return -ENODEV;
> > }
> >
> >- if (netdev_master_upper_dev_get(ndev)) {
> >+ rcu_read_lock();
> >+ /* We permit devices with VLAN attached to */
>
> I think that this comment might be misleading. Master upper is not set
> not only for VLAN but for macvlan (and in future possibly for others) as well.
>
OK, I will remove it.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2013-01-14 10:32 ` Jiri Pirko
2013-01-14 10:42 ` Cong Wang
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