Re: [PATCH] net/smc: Fix possible leaked pernet namespace in smc_init()

[Chen Zhongjin]

Hi,

On 2022/11/1 19:00, Tony Lu wrote:
> On Tue, Nov 01, 2022 at 05:37:22PM +0800, Chen Zhongjin wrote:
> > In smc_init(), register_pernet_subsys(&smc_net_stat_ops) is called
> > without any error handling.
> > If it fails, registering of &smc_net_ops won't be reverted.
> > And if smc_nl_init() fails, &smc_net_stat_ops itself won't be reverted.
> >
> > This leaves wild ops in subsystem linkedlist and when another module
> > tries to call register_pernet_operations() it triggers page fault:
> >
> > BUG: unable to handle page fault for address: fffffbfff81b964c
> > RIP: 0010:register_pernet_operations+0x1b9/0x5f0
> > Call Trace:
> >    <TASK>
> >    register_pernet_subsys+0x29/0x40
> >    ebtables_init+0x58/0x1000 [ebtables]
> >    ...
> >
> > Fixes: 194730a9beb5 ("net/smc: Make SMC statistics network namespace aware")
> > Signed-off-by: Chen Zhongjin <chenzhongjin@xxxxxxxxxx>
> This patch looks good to me.
>
> The subject of this patch should be in net, the prefix tag is missed.

Thanks for review and remind! I will add net tag for the next time I 
send patch to netdev.


Best,

Chen

> Reviewed-by: Tony Lu <tonylu@xxxxxxxxxxxxxxxxx>
>
> > ---
> >   net/smc/af_smc.c | 6 ++++--
> >   1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
> > index 3ccbf3c201cd..e12d4fa5aece 100644
> > --- a/net/smc/af_smc.c
> > +++ b/net/smc/af_smc.c
> > @@ -3380,14 +3380,14 @@ static int __init smc_init(void)
> >   
> >   	rc = register_pernet_subsys(&smc_net_stat_ops);
> >   	if (rc)
> > -		return rc;
> > +		goto out_pernet_subsys;
> >   
> >   	smc_ism_init();
> >   	smc_clc_init();
> >   
> >   	rc = smc_nl_init();
> >   	if (rc)
> > -		goto out_pernet_subsys;
> > +		goto out_pernet_subsys_stat;
> >   
> >   	rc = smc_pnet_init();
> >   	if (rc)
> > @@ -3480,6 +3480,8 @@ static int __init smc_init(void)
> >   	smc_pnet_exit();
> >   out_nl:
> >   	smc_nl_exit();
> > +out_pernet_subsys_stat:
> > +	unregister_pernet_subsys(&smc_net_stat_ops);
> >   out_pernet_subsys:
> >   	unregister_pernet_subsys(&smc_net_ops);
> >   
> > --
> > 2.17.1