uwb: properly check kthread_run return value

commit bbf26183b7a6236ba602f4d6a2f7cade35bba043 upstream.

uwbd_start() calls kthread_run() and checks that the return value is
not NULL. But the return value is not NULL in case kthread_run() fails,
it takes the form of ERR_PTR(-EINTR).

Use IS_ERR() instead.

Also add a check to uwbd_stop().

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 8 insertions, 4 deletions

diff --git a/drivers/uwb/uwbd.c b/drivers/uwb/uwbd.c
index bdcb13cc1d54..5c9828370217 100644
--- a/drivers/uwb/uwbd.c
+++ b/drivers/uwb/uwbd.c
@@ -303,18 +303,22 @@ static int uwbd(void *param)
 /** Start the UWB daemon */
 void uwbd_start(struct uwb_rc *rc)
 {
-        rc->uwbd.task = kthread_run(uwbd, rc, "uwbd");
-        if (rc->uwbd.task == NULL)
+        struct task_struct *task = kthread_run(uwbd, rc, "uwbd");
+        if (IS_ERR(task)) {
+                rc->uwbd.task = NULL;
                 printk(KERN_ERR "UWB: Cannot start management daemon; "
                        "UWB won't work\n");
-        else
+        } else {
+                rc->uwbd.task = task;
                 rc->uwbd.pid = rc->uwbd.task->pid;
+        }
 }
 
 /* Stop the UWB daemon and free any unprocessed events */
 void uwbd_stop(struct uwb_rc *rc)
 {
-        kthread_stop(rc->uwbd.task);
+        if (rc->uwbd.task)
+                kthread_stop(rc->uwbd.task);
         uwbd_flush(rc);
 }