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Subject[PATCH] af_key: fix netns ops ordering on module load/unload
On Fri, Jan 29, 2010 at 05:33:26PM +0100, Eric Dumazet wrote:
> @@ -3807,21 +3807,24 @@ static int __init ipsec_pfkey_init(void)
> if (err != 0)
> goto out;
>
> - err = sock_register(&pfkey_family_ops);
> - if (err != 0)
> - goto out_unregister_key_proto;
> err = xfrm_register_km(&pfkeyv2_mgr);
> if (err != 0)
> - goto out_sock_unregister;
> + goto out_unregister_key_proto;
> +
> err = register_pernet_subsys(&pfkey_net_ops);
> if (err != 0)
> goto out_xfrm_unregister_km;
> +
> + err = sock_register(&pfkey_family_ops);
> + if (err != 0)
> + goto out_unregister_pernet;
> out:
> return err;
> +
> +out_unregister_pernet:
> + unregister_pernet_subsys(&pfkey_net_ops);
> out_xfrm_unregister_km:
> xfrm_unregister_km(&pfkeyv2_mgr);
> -out_sock_unregister:
> - sock_unregister(PF_KEY);
> out_unregister_key_proto:
> proto_unregister(&key_proto);
> goto out;

ACK analysis, except this is not enough.

Here is patch which survived netns start/stop/modprobe/rmmod cycles.

Alexey, who still doesn't get why bug reproduces so easily for bug reporter.

Luca, please confirm.

Audit for the rest of the modules pending.

[PATCH] af_key: fix netns ops ordering on module load/unload

1. After sock_register() returns, it's possible to create sockets,
even if module still not initialized fully (blame generic module code
for that!)
2. Consequently, pfkey_create() can be called with pfkey_net_id still not
initialized which will BUG_ON in net_generic():
kernel BUG at include/net/netns/generic.h:43!
3. During netns shutdown, netns ops should be unregistered after
key manager unregistered because key manager calls can be triggered
from xfrm_user module:

general protection fault: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
pfkey_broadcast+0x111/0x210 [af_key]
pfkey_send_notify+0x16a/0x300 [af_key]
km_state_notify+0x41/0x70
xfrm_flush_sa+0x75/0x90 [xfrm_user]
4. Unregister netns ops after socket ops just in case and for symmetry.
Reported by Luca Tettamanti.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
---
net/key/af_key.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)
--- a/net/key/af_key.c
+++ b/net/key/af_key.c
@@ -3794,9 +3794,9 @@ static struct pernet_operations pfkey_net_ops = {

static void __exit ipsec_pfkey_exit(void)
{
- unregister_pernet_subsys(&pfkey_net_ops);
xfrm_unregister_km(&pfkeyv2_mgr);
sock_unregister(PF_KEY);
+ unregister_pernet_subsys(&pfkey_net_ops);
proto_unregister(&key_proto);
}

@@ -3807,21 +3807,22 @@ static int __init ipsec_pfkey_init(void)
if (err != 0)
goto out;

- err = sock_register(&pfkey_family_ops);
+ err = register_pernet_subsys(&pfkey_net_ops);
if (err != 0)
goto out_unregister_key_proto;
+ err = sock_register(&pfkey_family_ops);
+ if (err != 0)
+ goto out_unregister_pernet;
err = xfrm_register_km(&pfkeyv2_mgr);
if (err != 0)
goto out_sock_unregister;
- err = register_pernet_subsys(&pfkey_net_ops);
- if (err != 0)
- goto out_xfrm_unregister_km;
out:
return err;
-out_xfrm_unregister_km:
- xfrm_unregister_km(&pfkeyv2_mgr);
+
out_sock_unregister:
sock_unregister(PF_KEY);
+out_unregister_pernet:
+ unregister_pernet_subsys(&pfkey_net_ops);
out_unregister_key_proto:
proto_unregister(&key_proto);
goto out;

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