Linux 3.18.75

[thirdparty/kernel/stable-queue.git] / releases / 3.18.75 / uwb-properly-check-kthread_run-return-value.patch

From bbf26183b7a6236ba602f4d6a2f7cade35bba043 Mon Sep 17 00:00:00 2001
From: Andrey Konovalov <andreyknvl@google.com>
Date: Thu, 14 Sep 2017 14:30:55 +0200
Subject: uwb: properly check kthread_run return value

From: Andrey Konovalov <andreyknvl@google.com>

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>

---
 drivers/uwb/uwbd.c |   12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

--- 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);
 }