[PATCH 3.10 45/50] LOCKD: Fix a race when initialising nlmsvc_timeout

Greg Kroah-Hartman
2015-01-25T18:10:57Z

From: Trond Myklebust <trond.myklebust@primarydata.com>

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>
Cc: stable@vger.kernel.org # 3.10.x
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/lockd/svc.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

--- 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
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");