nfsd: call nfsd_last_thread() before final nfsd_put()

commit 2a501f55cd641eb4d3c16a2eab0d678693fac663 upstream.

If write_ports_addfd or write_ports_addxprt fail, they call nfsd_put()
without calling nfsd_last_thread().  This leaves nn->nfsd_serv pointing
to a structure that has been freed.

So remove 'static' from nfsd_last_thread() and call it when the
nfsd_serv is about to be destroyed.

Fixes: ec52361df99b ("SUNRPC: stop using ->sv_nrthreads as a refcount")
Signed-off-by: NeilBrown <neilb@suse.de>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index 7ed02fb..98854dd 100644 (file)
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -704,8 +704,10 @@ static ssize_t __write_ports_addfd(char *buf, struct net *net, const struct cred
 
        err = svc_addsock(nn->nfsd_serv, net, fd, buf, SIMPLE_TRANSACTION_LIMIT, cred);
 
-       if (err >= 0 &&
-           !nn->nfsd_serv->sv_nrthreads && !xchg(&nn->keep_active, 1))
+       if (err < 0 && !nn->nfsd_serv->sv_nrthreads && !nn->keep_active)
+               nfsd_last_thread(net);
+       else if (err >= 0 &&
+                !nn->nfsd_serv->sv_nrthreads && !xchg(&nn->keep_active, 1))
                svc_get(nn->nfsd_serv);
 
        nfsd_put(net);
@@ -756,6 +758,9 @@ out_close:
                svc_xprt_put(xprt);
        }
 out_err:
+       if (!nn->nfsd_serv->sv_nrthreads && !nn->keep_active)
+               nfsd_last_thread(net);
+
        nfsd_put(net);
        return err;
 }

diff --git a/fs/nfsd/nfsd.h b/fs/nfsd/nfsd.h
index 11c14fa..63deed2 100644 (file)
--- a/fs/nfsd/nfsd.h
+++ b/fs/nfsd/nfsd.h
@@ -138,6 +138,7 @@ int nfsd_vers(struct nfsd_net *nn, int vers, enum vers_op change);
 int nfsd_minorversion(struct nfsd_net *nn, u32 minorversion, enum vers_op change);
 void nfsd_reset_versions(struct nfsd_net *nn);
 int nfsd_create_serv(struct net *net);
+void nfsd_last_thread(struct net *net);
 
 extern int nfsd_max_blksize;
 

diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index 2114582..7ef6af9 100644 (file)
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -542,7 +542,7 @@ static struct notifier_block nfsd_inet6addr_notifier = {
 /* Only used under nfsd_mutex, so this atomic may be overkill: */
 static atomic_t nfsd_notifier_refcount = ATOMIC_INIT(0);
 
-static void nfsd_last_thread(struct net *net)
+void nfsd_last_thread(struct net *net)
 {
        struct nfsd_net *nn = net_generic(net, nfsd_net_id);
        struct svc_serv *serv = nn->nfsd_serv;