FAILED: patch "[PATCH] i2c: dev: check return value when calling dev_set_name()" failed to apply to 4.9-stable tree

FAILED: patch "[PATCH] i2c: dev: check return value when calling dev_set_name()" failed to apply to 4.9-stable tree

[gregkh]

The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 993eb48fa199b5f476df8204e652eff63dd19361 Mon Sep 17 00:00:00 2001
From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Date: Mon, 11 Apr 2022 21:07:51 +0300
Subject: [PATCH] i2c: dev: check return value when calling dev_set_name()

If dev_set_name() fails, the dev_name() is null, check the return
value of dev_set_name() to avoid the null-ptr-deref.

Fixes: 1413ef638aba ("i2c: dev: Fix the race between the release of i2c_dev and cdev")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

diff --git a/drivers/i2c/i2c-dev.c b/drivers/i2c/i2c-dev.c
index cf5d049342ea..6fd2b6718b08 100644
--- a/drivers/i2c/i2c-dev.c
+++ b/drivers/i2c/i2c-dev.c
@@ -668,16 +668,21 @@ static int i2cdev_attach_adapter(struct device *dev, void *dummy)
 	i2c_dev->dev.class = i2c_dev_class;
 	i2c_dev->dev.parent = &adap->dev;
 	i2c_dev->dev.release = i2cdev_dev_release;
-	dev_set_name(&i2c_dev->dev, "i2c-%d", adap->nr);
+
+	res = dev_set_name(&i2c_dev->dev, "i2c-%d", adap->nr);
+	if (res)
+		goto err_put_i2c_dev;
 
 	res = cdev_device_add(&i2c_dev->cdev, &i2c_dev->dev);
-	if (res) {
-		put_i2c_dev(i2c_dev, false);
-		return res;
-	}
+	if (res)
+		goto err_put_i2c_dev;
 
 	pr_debug("adapter [%s] registered as minor %d\n", adap->name, adap->nr);
 	return 0;
+
+err_put_i2c_dev:
+	put_i2c_dev(i2c_dev, false);
+	return res;
 }
 
 static int i2cdev_detach_adapter(struct device *dev, void *dummy)