The patch below does not apply to the 5.4-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)