Acked-by: Denis V. Lunev <den@xxxxxxxxxx>
On Fri, 2009-02-20 at 07:52 -0800, Eric W. Biederman wrote:
> Recently I had a kernel panic in icmp_send during a network namespace
> cleanup. There were packets in the arp queue that failed to be sent
> and we attempted to generate an ICMP host unreachable message, but
> failed because icmp_sk_exit had already been called.
>
> The network devices are removed from a network namespace and their
> arp queues are flushed before we do attempt to shutdown subsystems
> so this error should have been impossible.
>
> It turns out icmp_init is using register_pernet_device instead
> of register_pernet_subsys. Which resulted in icmp being shut down
> while we still had the possibility of packets in flight, making
> a nasty NULL pointer deference in interrupt context possible.
>
> Changing this to register_pernet_subsys fixes the problem in
> my testing.
>
> Signed-off-by: Eric W. Biederman <ebiederm@xxxxxxxxxxxxxxxxxx>
> ---
> net/ipv4/icmp.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
> index 382800a..3f50807 100644
> --- a/net/ipv4/icmp.c
> +++ b/net/ipv4/icmp.c
> @@ -1207,7 +1207,7 @@ static struct pernet_operations __net_initdata icmp_sk_ops = {
>
> int __init icmp_init(void)
> {
> - return register_pernet_device(&icmp_sk_ops);
> + return register_pernet_subsys(&icmp_sk_ops);
> }
>
> EXPORT_SYMBOL(icmp_err_convert);
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