linux-kernel - [PATCH] misc: bcm-vk: fix tty registration race

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Date:   Fri, 17 Sep 2021 13:57:36 +0200
From:   Johan Hovold <johan@...nel.org>
To:     Scott Branden <scott.branden@...adcom.com>
Cc:     Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        bcm-kernel-feedback-list@...adcom.com,
        linux-kernel@...r.kernel.org, Johan Hovold <johan@...nel.org>,
        stable@...r.kernel.org
Subject: [PATCH] misc: bcm-vk: fix tty registration race

Make sure to set the tty class-device driver data before registering the
tty to avoid having a racing open() dereference a NULL pointer.

Fixes: 91ca10d6fa07 ("misc: bcm-vk: add ttyVK support")
Cc: stable@...r.kernel.org      # 5.12
Signed-off-by: Johan Hovold <johan@...nel.org>
---
 drivers/misc/bcm-vk/bcm_vk_tty.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/misc/bcm-vk/bcm_vk_tty.c b/drivers/misc/bcm-vk/bcm_vk_tty.c
index 1b6076a89ca6..6669625ba4c8 100644
--- a/drivers/misc/bcm-vk/bcm_vk_tty.c
+++ b/drivers/misc/bcm-vk/bcm_vk_tty.c
@@ -267,13 +267,13 @@ int bcm_vk_tty_init(struct bcm_vk *vk, char *name)
 		struct device *tty_dev;
 
 		tty_port_init(&vk->tty[i].port);
-		tty_dev = tty_port_register_device(&vk->tty[i].port, tty_drv,
-						   i, dev);
+		tty_dev = tty_port_register_device_attr(&vk->tty[i].port,
+							tty_drv, i, dev, vk,
+							NULL);
 		if (IS_ERR(tty_dev)) {
 			err = PTR_ERR(tty_dev);
 			goto unwind;
 		}
-		dev_set_drvdata(tty_dev, vk);
 		vk->tty[i].is_opened = false;
 	}
 
-- 
2.32.0