[PATCH] mailbox: make the channel receive function robust

[Zhiqiang Hou]

From: Hou Zhiqiang <Zhiqiang.Hou@xxxxxxx>

Mailbox may receive fake messages on a channel without binding
to a client, this can result in kernel crash.

Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@xxxxxxx>
---
 drivers/mailbox/mailbox.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c
index bbc9fd75a95f7..1febfac5a85dd 100644
--- a/drivers/mailbox/mailbox.c
+++ b/drivers/mailbox/mailbox.c
@@ -145,7 +145,7 @@ static enum hrtimer_restart txdone_hrtimer(struct hrtimer *hrtimer)
 void mbox_chan_received_data(struct mbox_chan *chan, void *mssg)
 {
 	/* No buffering the received data */
-	if (chan->cl->rx_callback)
+	if (chan->cl && chan->cl->rx_callback)
 		chan->cl->rx_callback(chan->cl, mssg);
 }
 EXPORT_SYMBOL_GPL(mbox_chan_received_data);
-- 
2.43.0