LOCKD: Fix a race when initialising nlmsvc_timeout

commit 06bed7d18c2c07b3e3eeadf4bd357f6e806618cc upstream.

This commit fixes a race whereby nlmclnt_init() first starts the lockd
daemon, and then calls nlm_bind_host() with the expectation that
nlmsvc_timeout has already been initialised. Unfortunately, there is no
no synchronisation between lockd() and lockd_up() to guarantee that this
is the case.

Fix is to move the initialisation of nlmsvc_timeout into lockd_create_svc

Fixes: 9a1b6bf818e74 ("LOCKD: Don't call utsname()->nodename...")
Cc: Bruce Fields <bfields@fieldses.org>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c
index ec9e082f9ecd905af16f2dd09de37822376cfe66..3f5a7248e771a31ff60fe4419ff0287c3b209d48 100644 (file)
--- a/fs/lockd/svc.c
+++ b/fs/lockd/svc.c
@@ -137,10 +137,6 @@ lockd(void *vrqstp)
 
        dprintk("NFS locking service started (ver " LOCKD_VERSION ").\n");
 
-       if (!nlm_timeout)
-               nlm_timeout = LOCKD_DFLT_TIMEO;
-       nlmsvc_timeout = nlm_timeout * HZ;
-
        /*
         * The main request loop. We don't terminate until the last
         * NFS mount or NFS daemon has gone away.
@@ -346,6 +342,10 @@ static struct svc_serv *lockd_create_svc(void)
                printk(KERN_WARNING
                        "lockd_up: no pid, %d users??\n", nlmsvc_users);
 
+       if (!nlm_timeout)
+               nlm_timeout = LOCKD_DFLT_TIMEO;
+       nlmsvc_timeout = nlm_timeout * HZ;
+
        serv = svc_create(&nlmsvc_program, LOCKD_BUFSIZE, NULL);
        if (!serv) {
                printk(KERN_WARNING "lockd_up: create service failed\n");