Mailbox: Check valid registered callback before calling

This patch checks if the mailbox user has assinged a valid
callback fuction before calling it.

Signed-off-by: Fernando Guzman Lugo <x0095840@ti.com>
Signed-off-by: Hiroshi DOYU <Hiroshi.DOYU@nokia.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/arch/arm/plat-omap/mailbox.c b/arch/arm/plat-omap/mailbox.c
index 77c23f5a0037..72efbe5be578 100644
--- a/arch/arm/plat-omap/mailbox.c
+++ b/arch/arm/plat-omap/mailbox.c
@@ -146,7 +146,8 @@ static void mbox_rx_work(struct work_struct *work)
 
                 msg = (mbox_msg_t)rq->special;
                 blk_end_request_all(rq, 0);
-                mbox->rxq->callback((void *)msg);
+                if (mbox->rxq->callback)
+                        mbox->rxq->callback((void *)msg);
         }
 }