patch "serial: sprd: Fix a dereference warning" added to tty-next

patch "serial: sprd: Fix a dereference warning" added to tty-next

[gregkh]

This is a note to let you know that I've just added the patch titled

    serial: sprd: Fix a dereference warning

to my tty git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git
in the tty-next branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will also be merged in the next major kernel release
during the merge window.

If you have any questions about this process, please let me know.


From efc176929a3505a30c3993ddd393b40893649bd2 Mon Sep 17 00:00:00 2001
From: Lanqing Liu <liuhhome@gmail.com>
Date: Mon, 16 Mar 2020 11:13:33 +0800
Subject: serial: sprd: Fix a dereference warning

We should validate if the 'sup' is NULL or not before freeing DMA
memory, to fix below warning.

"drivers/tty/serial/sprd_serial.c:1141 sprd_remove()
 error: we previously assumed 'sup' could be null (see line 1132)"

Fixes: f4487db58eb7 ("serial: sprd: Add DMA mode support")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Lanqing Liu <liuhhome@gmail.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/e2bd92691538e95b04a2c2a728f3292e1617018f.1584325957.git.liuhhome@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/tty/serial/sprd_serial.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/tty/serial/sprd_serial.c b/drivers/tty/serial/sprd_serial.c
index 914862844790..509781ee26bf 100644
--- a/drivers/tty/serial/sprd_serial.c
+++ b/drivers/tty/serial/sprd_serial.c
@@ -1132,14 +1132,13 @@ static int sprd_remove(struct platform_device *dev)
 	if (sup) {
 		uart_remove_one_port(&sprd_uart_driver, &sup->port);
 		sprd_port[sup->port.line] = NULL;
+		sprd_rx_free_buf(sup);
 		sprd_ports_num--;
 	}
 
 	if (!sprd_ports_num)
 		uart_unregister_driver(&sprd_uart_driver);
 
-	sprd_rx_free_buf(sup);
-
 	return 0;
 }
 
-- 
2.25.1