On Fri, Apr 27, 2012 at 06:08:13PM +0400, Stanislav Kinsbursky wrote:
> On 27.04.2012 17:55, J. Bruce Fields wrote:
> >On Wed, Apr 25, 2012 at 05:37:49PM +0400, Stanislav Kinsbursky wrote:
> >>Registering service with svc_bind() can fail. In this case service will be
> >>destroyed and during destruction it will try to unregister itself from rpcbind.
> >>In this case unregister have to be skipped.
> >
> >Isn't this a preexisting bug, in which case perhaps Trond should at it
> >to his list of bugs to submit now?
> >
>
> Not it's not.
>
> Previously, in case of bind operations failure, rpcb_put_local()
> wasn't called, but service data was destroyed instead:
>
> - if (svc_uses_rpcbind(serv)) {
> - if (svc_rpcb_setup(serv, current->nsproxy->net_ns) < 0) {
> - kfree(serv->sv_pools);
> - kfree(serv);
> - return NULL;
> - }
> - if (!serv->sv_shutdown)
> - serv->sv_shutdown = svc_rpcb_cleanup;
> - }
>
> Now (with svc_bind() introduction) service can be created, but
> svc_bind() could fail. And thus svc_destroy() have to be called.
> Which will call rpcb_put_local().
>
> And the problem here that svc_bind() can fail before incrementing of
> rpcb usage counter.
OK, but then you're fixing a bug that you just introduced with the
previous patch.
So this should be combined with the previous patch.
--b.
>
> >--b.
> >
> >>
> >>Signed-off-by: Stanislav Kinsbursky<skinsbursky@xxxxxxxxxxxxx>
> >>
> >>---
> >> net/sunrpc/rpcb_clnt.c | 12 +++++++-----
> >> 1 files changed, 7 insertions(+), 5 deletions(-)
> >>
> >>diff --git a/net/sunrpc/rpcb_clnt.c b/net/sunrpc/rpcb_clnt.c
> >>index 78ac39f..4c38b33 100644
> >>--- a/net/sunrpc/rpcb_clnt.c
> >>+++ b/net/sunrpc/rpcb_clnt.c
> >>@@ -180,14 +180,16 @@ void rpcb_put_local(struct net *net)
> >> struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
> >> struct rpc_clnt *clnt = sn->rpcb_local_clnt;
> >> struct rpc_clnt *clnt4 = sn->rpcb_local_clnt4;
> >>- int shutdown;
> >>+ int shutdown = 0;
> >>
> >> spin_lock(&sn->rpcb_clnt_lock);
> >>- if (--sn->rpcb_users == 0) {
> >>- sn->rpcb_local_clnt = NULL;
> >>- sn->rpcb_local_clnt4 = NULL;
> >>+ if (sn->rpcb_users) {
> >>+ if (--sn->rpcb_users == 0) {
> >>+ sn->rpcb_local_clnt = NULL;
> >>+ sn->rpcb_local_clnt4 = NULL;
> >>+ }
> >>+ shutdown = !sn->rpcb_users;
> >> }
> >>- shutdown = !sn->rpcb_users;
> >> spin_unlock(&sn->rpcb_clnt_lock);
> >>
> >> if (shutdown) {
> >>
>
>
> --
> Best regards,
> Stanislav Kinsbursky
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