[PATCH] HID: nintendo: fix rumble worker null pointer deref

["Daniel J. Ogorchock" <djogorchock@gmail.com>]

We can dereference a null pointer trying to queue work to a destroyed
workqueue.

If the device is disconnected, nintendo_hid_remove is called, in which
the rumble_queue is destroyed. Avoid using that queue to defer rumble
work once the controller state is set to JOYCON_CTLR_STATE_REMOVED.

This eliminates the null pointer dereference.

Signed-off-by: Daniel J. Ogorchock <djogorchock@gmail.com>
---
 drivers/hid/hid-nintendo.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/hid/hid-nintendo.c b/drivers/hid/hid-nintendo.c
index 2204de889739f..98551a3087c3b 100644
--- a/drivers/hid/hid-nintendo.c
+++ b/drivers/hid/hid-nintendo.c
@@ -1222,6 +1222,7 @@ static void joycon_parse_report(struct joycon_ctlr *ctlr,
 
 	spin_lock_irqsave(&ctlr->lock, flags);
 	if (IS_ENABLED(CONFIG_NINTENDO_FF) && rep->vibrator_report &&
+	    ctlr->ctlr_state != JOYCON_CTLR_STATE_REMOVED &&
 	    (msecs - ctlr->rumble_msecs) >= JC_RUMBLE_PERIOD_MS &&
 	    (ctlr->rumble_queue_head != ctlr->rumble_queue_tail ||
 	     ctlr->rumble_zero_countdown > 0)) {
@@ -1546,12 +1547,13 @@ static int joycon_set_rumble(struct joycon_ctlr *ctlr, u16 amp_r, u16 amp_l,
 		ctlr->rumble_queue_head = 0;
 	memcpy(ctlr->rumble_data[ctlr->rumble_queue_head], data,
 	       JC_RUMBLE_DATA_SIZE);
-	spin_unlock_irqrestore(&ctlr->lock, flags);
 
 	/* don't wait for the periodic send (reduces latency) */
-	if (schedule_now)
+	if (schedule_now && ctlr->ctlr_state != JOYCON_CTLR_STATE_REMOVED)
 		queue_work(ctlr->rumble_queue, &ctlr->rumble_worker);
 
+	spin_unlock_irqrestore(&ctlr->lock, flags);
+
 	return 0;
 }
 
-- 
2.37.1