[PATCH 1/5] nfsd: call nfsd_last_thread() before final nfsd_put()

NeilBrown
2023-12-15T01:00:55Z

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.

Signed-off-by: NeilBrown <neilb@suse.de>
---
fs/nfsd/nfsctl.c | 9 +++++++--
fs/nfsd/nfsd.h | 1 +
fs/nfsd/nfssvc.c | 2 +-
3 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index d6eeee149370..8c84e77a8892 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -709,8 +709,10 @@ 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);
@@ -761,6 +763,9 @@ static ssize_t __write_ports_addxprt(char *buf, struct net *net, const struct cr
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 f5ff42f41ee7..3286ffacbc56 100644
--- a/fs/nfsd/nfsd.h
+++ b/fs/nfsd/nfsd.h
@@ -155,6 +155,7 @@ 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 66ca50b38b27..32d06249b3c0 100644
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -541,7 +541,7 @@ 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;
--
2.43.0