LinuxLists.cc - [PATCH] netconsole: take care of NETDEV

2009-04-29 20:47:24

Subject: [PATCH] netconsole: take care of NETDEV_UNREGISTER event

When netconsole is loaded and a network interface fades away (e.g. on
rmmod $interface_driver_module) the rmmod remains stuck and some locks
are taken that prevent any additional module loading/unloading as well
as interface up/down changes.
In addition kernel logs (and console) get flooded at 10s interval with

[ 122.464065] unregister_netdevice: waiting for eth0 to become free. Usage count = 1
[ 132.704059] unregister_netdevice: waiting for eth0 to become free. Usage count = 1

This patch lets netconsole take NETDEV_UNREGISTER event into account
and release the affected interface if it was in use.

Signed-off-by: Bruno Prémont <[email protected]>
---
diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index eceadf7..bf4af52 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -664,7 +664,7 @@ static int netconsole_netdev_event(struct notifier_block *this,
struct netconsole_target *nt;
struct net_device *dev = ptr;

- if (!(event == NETDEV_CHANGENAME))
+ if (!(event == NETDEV_CHANGENAME || event == NETDEV_UNREGISTER))
goto done;

spin_lock_irqsave(&target_list_lock, flags);
@@ -675,6 +675,15 @@ static int netconsole_netdev_event(struct notifier_block *this,
case NETDEV_CHANGENAME:
strlcpy(nt->np.dev_name, dev->name, IFNAMSIZ);
break;
+ case NETDEV_UNREGISTER:
+ if (!nt->enabled)
+ break;
+ netpoll_cleanup(&nt->np);
+ nt->enabled = 0;
+ printk(KERN_INFO "netconsole: network logging stopped"
+ ", interface %s unregistered\n",
+ dev->name);
+ break;
}
}
netconsole_target_put(nt);

2009-04-29 20:56:37

by Bruno Prémont

[permalink] [raw]

Subject: Re: [PATCH] netconsole: take care of NETDEV_UNREGISTER event

(fix netdev CC)

The printk line is slightly over 80 though I have no better idea
for the line-wrapping while keeping it searchable with grep.

Bruno

On Wed, 29 April 2009 Bruno Prémont <[email protected]> wrote:
> When netconsole is loaded and a network interface fades away (e.g. on
> rmmod $interface_driver_module) the rmmod remains stuck and some locks
> are taken that prevent any additional module loading/unloading as well
> as interface up/down changes.
> In addition kernel logs (and console) get flooded at 10s interval with
>
> [ 122.464065] unregister_netdevice: waiting for eth0 to become free.
> Usage count = 1 [ 132.704059] unregister_netdevice: waiting for eth0
> to become free. Usage count = 1
>
> This patch lets netconsole take NETDEV_UNREGISTER event into account
> and release the affected interface if it was in use.
>
> Signed-off-by: Bruno Prémont <[email protected]>
> ---
> diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
> index eceadf7..bf4af52 100644
> --- a/drivers/net/netconsole.c
> +++ b/drivers/net/netconsole.c
> @@ -664,7 +664,7 @@ static int netconsole_netdev_event(struct
> notifier_block *this, struct netconsole_target *nt;
> struct net_device *dev = ptr;
>
> - if (!(event == NETDEV_CHANGENAME))
> + if (!(event == NETDEV_CHANGENAME || event == NETDEV_UNREGISTER))
> goto done;
>
> spin_lock_irqsave(&target_list_lock, flags);
> @@ -675,6 +675,15 @@ static int netconsole_netdev_event(struct
> notifier_block *this, case NETDEV_CHANGENAME:
> strlcpy(nt->np.dev_name, dev->name,
> IFNAMSIZ); break;
> + case NETDEV_UNREGISTER:
> + if (!nt->enabled)
> + break;
> + netpoll_cleanup(&nt->np);
> + nt->enabled = 0;
> + printk(KERN_INFO "netconsole: network logging stopped"
> + ", interface %s unregistered\n",
> + dev->name);
> + break;
> }
> }
> netconsole_target_put(nt);

2009-04-29 21:44:40

by David Miller

[permalink] [raw]

Subject: Re: [PATCH] netconsole: take care of NETDEV_UNREGISTER event

From: Bruno Pr?mont <[email protected]>
Date: Wed, 29 Apr 2009 22:56:25 +0200

> (fix netdev CC)

Please make a fresh submission with the correct netdev
address so that your patch is properly tracked at:

http://patchwork.ozlabs.org/project/netdev/list/

Thank you.

2009-04-30 06:55:42

by Bruno Prémont

[permalink] [raw]

Subject: Re: [PATCH, resend] netconsole: take care of NETDEV_UNREGISTER event

2009-04-30 16:49:27

by Matt Mackall

[permalink] [raw]

Subject: Re: [PATCH, resend] netconsole: take care of NETDEV_UNREGISTER event

On Thu, 2009-04-30 at 08:45 +0200, Bruno Prémont wrote:
> When netconsole is loaded and a network interface fades away (e.g. on
> rmmod $interface_driver_module) the rmmod remains stuck and some locks
> are taken that prevent any additional module loading/unloading as well
> as interface up/down changes.
> In addition kernel logs (and console) get flooded at 10s interval with
>
> [ 122.464065] unregister_netdevice: waiting for eth0 to become free. Usage count = 1
> [ 132.704059] unregister_netdevice: waiting for eth0 to become free. Usage count = 1
>
> This patch lets netconsole take NETDEV_UNREGISTER event into account
> and release the affected interface if it was in use.
>
> Signed-off-by: Bruno Prémont <[email protected]>

Acked-by: Matt Mackall <[email protected]>

> ---
> diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
> index eceadf7..bf4af52 100644
> --- a/drivers/net/netconsole.c
> +++ b/drivers/net/netconsole.c
> @@ -664,7 +664,7 @@ static int netconsole_netdev_event(struct notifier_block *this,
> struct netconsole_target *nt;
> struct net_device *dev = ptr;
>
> - if (!(event == NETDEV_CHANGENAME))
> + if (!(event == NETDEV_CHANGENAME || event == NETDEV_UNREGISTER))
> goto done;
>
> spin_lock_irqsave(&target_list_lock, flags);
> @@ -675,6 +675,15 @@ static int netconsole_netdev_event(struct notifier_block *this,
> case NETDEV_CHANGENAME:
> strlcpy(nt->np.dev_name, dev->name, IFNAMSIZ);
> break;
> + case NETDEV_UNREGISTER:
> + if (!nt->enabled)
> + break;
> + netpoll_cleanup(&nt->np);
> + nt->enabled = 0;
> + printk(KERN_INFO "netconsole: network logging stopped"
> + ", interface %s unregistered\n",
> + dev->name);
> + break;
> }
> }
> netconsole_target_put(nt);
> --
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