Pavel Emelyanov wrote:
> Roel Kluin wrote:
>> I got this bug recently, I am not sure whether this is related to any
>> previously
>> reported ones. It was a recently pulled git kernel. Also I have been hacking
>> my
>> kernel a bit lately, but I think that I haven't got any changes in the
>> currently
>> running kernel.
>>
>> FYI: my network card was not running (module not loaded, and I just started
>> thunderbird)
>>
>> Roel
>>
>> More information needed?
>
> I've tried to objdump my ipv6.ko, and found (at the different offset,
> but) the same codeline. It showed that the buggy place was in:
>
> list_for_each_rcu(p, &inetsw6[sock->type]) {
>
> some list_head pointer was NULL.
>
> I looked at the inet6_init (which seems to run at the moment of the
> oops according to the calltrace) and found that the ipv6 protocol
> is first registered and only after this the inetsw6 lists are
> properly initialized.
Hm... A deeper look at the code showed that the proto_register() is
OK to be called before the list initialization.
Nevertheless, the faulty place is found correctly (providing that
Roel's objdump looks similar to mine, but it should - this codeline
is unique in the ipv6.ko).
Roel, are you sure, that the kernel you're running is not hacked
by some of you patches :)
> I suspect that this is a race: we create the socket right after
> the new protocol is registered, but before the list heads are
> ready. The ->init call is called without the stopmachine, so
> other process run in parallel with it.
>
> This patch should help, but I don't think that such a situation
> is easily reproducible.
>
> Signed-off-by: Pavel Emelyanov <[EMAIL PROTECTED]>
>
> ---
>
> diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
> index ecbd388..f9bd26f 100644
> --- a/net/ipv6/af_inet6.c
> +++ b/net/ipv6/af_inet6.c
> @@ -769,6 +769,10 @@ static int __init inet6_init(void)
> #endif
> #endif
>
> + /* Register the socket-side information for inet6_create. */
> + for(r = &inetsw6[0]; r < &inetsw6[SOCK_MAX]; ++r)
> + INIT_LIST_HEAD(r);
> +
> err = proto_register(&tcpv6_prot, 1);
> if (err)
> goto out;
> @@ -786,10 +790,6 @@ static int __init inet6_init(void)
> goto out_unregister_udplite_proto;
>
>
> - /* Register the socket-side information for inet6_create. */
> - for(r = &inetsw6[0]; r < &inetsw6[SOCK_MAX]; ++r)
> - INIT_LIST_HEAD(r);
> -
> /* We MUST register RAW sockets before we create the ICMP6,
> * IGMP6, or NDISC control sockets.
> */
>
-
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