On Thu, 30 Jun 2016, J. Bruce Fields wrote:
> On Thu, Jun 30, 2016 at 10:39:32AM -0400, Scott Mayhew wrote:
> > If the lockd service fails to start up then we need to be sure that the
> > notifier blocks are not registered, otherwise a subsequent start of the
> > service could cause the same notifier to be registered twice, leading to
> > soft lockups.
>
> Good catch, thanks!
>
> I think the following (untested) should do the same job slightly more
> concisely?
Yes, that works too. Thanks.
-Scott
>
> --b.
>
> commit d2f017465698
> Author: Scott Mayhew <smayhew@xxxxxxxxxx>
> Date: Thu Jun 30 10:39:32 2016 -0400
>
> lockd: unregister notifier blocks if the service fails to come up completely
>
> If the lockd service fails to start up then we need to be sure that the
> notifier blocks are not registered, otherwise a subsequent start of the
> service could cause the same notifier to be registered twice, leading to
> soft lockups.
>
> Signed-off-by: Scott Mayhew <smayhew@xxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: 0751ddf77b6a "lockd: Register callbacks on the inetaddr_chain..."
> Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
>
> diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c
> index 154a107cd376..fc4084ef4736 100644
> --- a/fs/lockd/svc.c
> +++ b/fs/lockd/svc.c
> @@ -335,12 +335,17 @@ static struct notifier_block lockd_inet6addr_notifier = {
> };
> #endif
>
> -static void lockd_svc_exit_thread(void)
> +static void lockd_unregister_notifiers(void)
> {
> unregister_inetaddr_notifier(&lockd_inetaddr_notifier);
> #if IS_ENABLED(CONFIG_IPV6)
> unregister_inet6addr_notifier(&lockd_inet6addr_notifier);
> #endif
> +}
> +
> +static void lockd_svc_exit_thread(void)
> +{
> + lockd_unregister_notifiers();
> svc_exit_thread(nlmsvc_rqst);
> }
>
> @@ -462,7 +467,7 @@ int lockd_up(struct net *net)
> * Note: svc_serv structures have an initial use count of 1,
> * so we exit through here on both success and failure.
> */
> -err_net:
> +err_put:
> svc_destroy(serv);
> err_create:
> mutex_unlock(&nlmsvc_mutex);
> @@ -470,7 +475,9 @@ err_create:
>
> err_start:
> lockd_down_net(serv, net);
> - goto err_net;
> +err_net:
> + lockd_unregister_notifiers();
> + goto err_put;
> }
> EXPORT_SYMBOL_GPL(lockd_up);
>
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