netdev - Re[2]: [PATCH 2/2] IPVS: make failure of netns init more stable

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Message-ID: <alpine.LFD.2.00.1204182306380.2017@ja.ssi.bg>
Date:	Wed, 18 Apr 2012 23:27:02 +0300 (EEST)
From:	Julian Anastasov <ja@....bg>
To:	Hans Schillstrom <hans@...illstrom.com>
cc:	"horms@...ge.net.au" <horms@...ge.net.au>,
	Hans Schillstrom <hans.schillstrom@...csson.com>,
	"wensong@...ux-vs.org" <wensong@...ux-vs.org>,
	"lvs-devel@...r.kernel.org" <lvs-devel@...r.kernel.org>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	"netfilter-devel@...r.kernel.org" <netfilter-devel@...r.kernel.org>
Subject: Re[2]:  [PATCH 2/2] IPVS: make failure of netns init more  stable


	Hello,

On Wed, 18 Apr 2012, Hans Schillstrom wrote:

> >trigger load error. When I generate ENOMEM on IPVS core init
> >for such case I get ENOENT from register_ip_vs_app when
> >patch 1 and 2 for apps are applied, i.e. net->ipvs is NULL.
> >You can check it with NF_CONNTRACK=y, IP_VS=y and
> >IP_VS_FTP=m. You only need to trigger ENOMEM in __ip_vs_init.
> 
> 
> I did test this with 4 netns loaded and modprobe ip_vs_ftp
> In the 4:th netns  (ipvs->gen >= 4) fire a -ENOMEM 
> The result was as expected, ip_vs_ftp was not loaded.
> 
> All patches below was loaded. (included the ipvs NULL check)
> 
> Just for "fun" I also added a printk in the ipvs NULL check
> but I can't trigger it. 

	I trigger it in this way (ip_vs in kernel, ip_vs_ftp
as module):

        if (1 || ip_vs_app_net_init(net) < 0)
                goto app_fail;

	This causes ip_vs core to fail. I use NET_NS=n.

> Simon:
>  do you have any possibility to test it or give me a hint how to do ?
> (Just to make sure that the patches below will be sufficient)
> 
> >
> >> With proper fault handling i.e. all ways returning fault codes to the netns init,
> >> there is no need for checking for  "if (!net->ipvs)" or any other action.
> >
> >	Probably but one check on load does not hurt much.
> 
> I think I have tested all of above now and my conclusion is that we need the following patches
> which also was applied when the tests was run.
> (with a small reservation that I might have missed some..)
> 
> [PATCH v3 1/2] netfilter: ipvs: Verify that IP_VS protocol has been registered, Sasha Levin
> [PATCH v3 2/2] netfilter: ipvs: use GFP_KERNEL allocation where possible, Sasha Levin
> 
> [PATCH 0/6] Convert some GFP_ATOMIC allocations, Julian Anastasov
> [PATCH 1/6] ipvs: timeout tables do not need GFP_ATOMIC allocation, Julian Anastasov
> [PATCH 2/6] ipvs: SH scheduler does not need GFP_ATOMIC allocation, Julian Anastasov
> [PATCH 5/6] ipvs: LBLCR scheduler does not need GFP_ATOMIC allocation on init, Julian Anastasov
> [PATCH 6/6] ipvs: WRR scheduler does not need GFP_ATOMIC allocation, Julian Anastasov
> [PATCH 3/6] ipvs: DH scheduler does not need GFP_ATOMIC allocation, Julian Anastasov
> [PATCH 4/6] ipvs: LBLC scheduler does not need GFP_ATOMIC allocation on init, Julian Anastasov
> 
> [PATCH] ipvs: fix crash in ip_vs_control_net_cleanup on unload, Julian Anastasov
> 
> [PATCH 1/2] ipvs: reset ipvs pointer in netns, Julian Anastasov
> [PATCH 1/2] IPVS: take care of return value from protocol init_netns, Hans Schillstrom
> 
> To be safe,  add this to  [PATCH 1/2] ipvs: reset ipvs pointer in netns or make a new patch

	The ip_vs_ftp part is fixed by:
"[PATCH 2/2] ipvs: fix app registration in netns". So, this check
for ip_vs_ftp is not needed anymore:

> diff --git a/net/netfilter/ipvs/ip_vs_ftp.c b/net/netfilter/ipvs/ip_vs_ftp.c
> index 538d74e..c757359 100644
> --- a/net/netfilter/ipvs/ip_vs_ftp.c
> +++ b/net/netfilter/ipvs/ip_vs_ftp.c
> @@ -439,6 +439,9 @@ static int __net_init __ip_vs_ftp_init(struct net *net)
>         struct ip_vs_app *app;
>         struct netns_ipvs *ipvs = net_ipvs(net);
>  
> +       if (!ipvs)
> +               return ERR_PTR(-ENOENT);
> +
>         app = kmemdup(&ip_vs_ftp, sizeof(struct ip_vs_app), GFP_KERNEL);
>         if (!app)
>                 return -ENOMEM;
> 
> diff --git a/net/netfilter/ipvs/ip_vs_lblc.c b/net/netfilter/ipvs/ip_vs_lblc.c
> index 74c7278..1d74996 100644
> --- a/net/netfilter/ipvs/ip_vs_lblc.c
> +++ b/net/netfilter/ipvs/ip_vs_lblc.c
> @@ -549,6 +549,9 @@ static int __net_init __ip_vs_lblc_init(struct net *net)
>  {
>         struct netns_ipvs *ipvs = net_ipvs(net);
>  
> +       if (!ipvs)
> +               return ERR_PTR(-ENOENT);

	You can post additional patches for lblc and lblcr but
use 'return -ENOENT;', ERR_PTR is not appropriate here, it
is for pointers.

> +
>         if (!net_eq(net, &init_net)) {
>                 ipvs->lblc_ctl_table = kmemdup(vs_vars_table,
>                                                 sizeof(vs_vars_table),
> diff --git a/net/netfilter/ipvs/ip_vs_lblcr.c b/net/netfilter/ipvs/ip_vs_lblcr.c
> index 8620c68..c328ee0 100644
> --- a/net/netfilter/ipvs/ip_vs_lblcr.c
> +++ b/net/netfilter/ipvs/ip_vs_lblcr.c
> @@ -743,6 +743,9 @@ static int __net_init __ip_vs_lblcr_init(struct net *net)
>  {
>         struct netns_ipvs *ipvs = net_ipvs(net);
>  
> +       if (!ipvs)
> +               return ERR_PTR(-ENOENT);
> +
>         if (!net_eq(net, &init_net)) {
>                 ipvs->lblcr_ctl_table = kmemdup(vs_vars_table,
>                                                 sizeof(vs_vars_table),

Regards

--
Julian Anastasov <ja@....bg>
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