lockd: close potential race with rapid lockd_up/lockd_down cycle
If lockd_down is called very rapidly after lockd_up returns, then there is a slim chance that lockd() will never be called. kthread() will return before calling the function, so we'll end up never actually calling the cleanup functions for the thread. Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
This commit is contained in:
parent
a75c5d01e4
commit
abd1ec4efd
|
@ -50,7 +50,7 @@ EXPORT_SYMBOL(nlmsvc_ops);
|
|||
static DEFINE_MUTEX(nlmsvc_mutex);
|
||||
static unsigned int nlmsvc_users;
|
||||
static struct task_struct *nlmsvc_task;
|
||||
static struct svc_serv *nlmsvc_serv;
|
||||
static struct svc_rqst *nlmsvc_rqst;
|
||||
int nlmsvc_grace_period;
|
||||
unsigned long nlmsvc_timeout;
|
||||
|
||||
|
@ -194,20 +194,11 @@ lockd(void *vrqstp)
|
|||
|
||||
svc_process(rqstp);
|
||||
}
|
||||
|
||||
flush_signals(current);
|
||||
if (nlmsvc_ops)
|
||||
nlmsvc_invalidate_all();
|
||||
nlm_shutdown_hosts();
|
||||
|
||||
unlock_kernel();
|
||||
|
||||
nlmsvc_task = NULL;
|
||||
nlmsvc_serv = NULL;
|
||||
|
||||
/* Exit the RPC thread */
|
||||
svc_exit_thread(rqstp);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
|
@ -254,16 +245,15 @@ int
|
|||
lockd_up(int proto) /* Maybe add a 'family' option when IPv6 is supported ?? */
|
||||
{
|
||||
struct svc_serv *serv;
|
||||
struct svc_rqst *rqstp;
|
||||
int error = 0;
|
||||
|
||||
mutex_lock(&nlmsvc_mutex);
|
||||
/*
|
||||
* Check whether we're already up and running.
|
||||
*/
|
||||
if (nlmsvc_serv) {
|
||||
if (nlmsvc_rqst) {
|
||||
if (proto)
|
||||
error = make_socks(nlmsvc_serv, proto);
|
||||
error = make_socks(nlmsvc_rqst->rq_server, proto);
|
||||
goto out;
|
||||
}
|
||||
|
||||
|
@ -288,9 +278,10 @@ lockd_up(int proto) /* Maybe add a 'family' option when IPv6 is supported ?? */
|
|||
/*
|
||||
* Create the kernel thread and wait for it to start.
|
||||
*/
|
||||
rqstp = svc_prepare_thread(serv, &serv->sv_pools[0]);
|
||||
if (IS_ERR(rqstp)) {
|
||||
error = PTR_ERR(rqstp);
|
||||
nlmsvc_rqst = svc_prepare_thread(serv, &serv->sv_pools[0]);
|
||||
if (IS_ERR(nlmsvc_rqst)) {
|
||||
error = PTR_ERR(nlmsvc_rqst);
|
||||
nlmsvc_rqst = NULL;
|
||||
printk(KERN_WARNING
|
||||
"lockd_up: svc_rqst allocation failed, error=%d\n",
|
||||
error);
|
||||
|
@ -298,16 +289,15 @@ lockd_up(int proto) /* Maybe add a 'family' option when IPv6 is supported ?? */
|
|||
}
|
||||
|
||||
svc_sock_update_bufs(serv);
|
||||
nlmsvc_serv = rqstp->rq_server;
|
||||
|
||||
nlmsvc_task = kthread_run(lockd, rqstp, serv->sv_name);
|
||||
nlmsvc_task = kthread_run(lockd, nlmsvc_rqst, serv->sv_name);
|
||||
if (IS_ERR(nlmsvc_task)) {
|
||||
error = PTR_ERR(nlmsvc_task);
|
||||
svc_exit_thread(nlmsvc_rqst);
|
||||
nlmsvc_task = NULL;
|
||||
nlmsvc_serv = NULL;
|
||||
nlmsvc_rqst = NULL;
|
||||
printk(KERN_WARNING
|
||||
"lockd_up: kthread_run failed, error=%d\n", error);
|
||||
svc_exit_thread(rqstp);
|
||||
goto destroy_and_out;
|
||||
}
|
||||
|
||||
|
@ -346,6 +336,9 @@ lockd_down(void)
|
|||
BUG();
|
||||
}
|
||||
kthread_stop(nlmsvc_task);
|
||||
svc_exit_thread(nlmsvc_rqst);
|
||||
nlmsvc_task = NULL;
|
||||
nlmsvc_rqst = NULL;
|
||||
out:
|
||||
mutex_unlock(&nlmsvc_mutex);
|
||||
}
|
||||
|
|
Loading…
Reference in a new issue