[PATCH 5.10.y] i2c: dev: check return value when calling dev_set_name()

[PATCH 5.10.y] i2c: dev: check return value when calling dev_set_name()

[Feng Liu]

From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

[ Upstream commit 993eb48fa199b5f476df8204e652eff63dd19361 ]

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>
Signed-off-by: Feng Liu <Feng.Liu3@windriver.com>
Signed-off-by: He Zhe <Zhe.He@windriver.com>

---
Verified the build test.
---
 drivers/i2c/i2c-dev.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/i2c/i2c-dev.c b/drivers/i2c/i2c-dev.c
index dafad891998e..f0bd4ae19df6 100644
--- a/drivers/i2c/i2c-dev.c
+++ b/drivers/i2c/i2c-dev.c
@@ -669,17 +669,22 @@ 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("i2c-dev: 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)
-- 
2.34.1

Re: [PATCH 5.10.y] i2c: dev: check return value when calling dev_set_name()

[Sasha Levin]

[ Sasha's backport helper bot ]

Hi,

✅ All tests passed successfully. No issues detected.
No action required from the submitter.

The upstream commit SHA1 provided is correct: 993eb48fa199b5f476df8204e652eff63dd19361

WARNING: Author mismatch between patch and upstream commit:
Backport author: Feng Liu<Feng.Liu3@windriver.com>
Commit author: Andy Shevchenko<andriy.shevchenko@linux.intel.com>

Status in newer kernel trees:
6.13.y | Present (exact SHA1)
6.12.y | Present (exact SHA1)
6.6.y | Present (exact SHA1)
6.1.y | Present (exact SHA1)
5.15.y | Present (different SHA1: 2f345bb14ad4)

Note: The patch differs from the upstream commit:
---
1:  993eb48fa199b ! 1:  011fada4599a5 i2c: dev: check return value when calling dev_set_name()
    @@ Metadata
      ## Commit message ##
         i2c: dev: check return value when calling dev_set_name()
     
    +    [ Upstream commit 993eb48fa199b5f476df8204e652eff63dd19361 ]
    +
         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>
    +    Signed-off-by: Feng Liu <Feng.Liu3@windriver.com>
    +    Signed-off-by: He Zhe <Zhe.He@windriver.com>
     
      ## drivers/i2c/i2c-dev.c ##
     @@ drivers/i2c/i2c-dev.c: static int i2cdev_attach_adapter(struct device *dev, void *dummy)
    @@ drivers/i2c/i2c-dev.c: static int i2cdev_attach_adapter(struct device *dev, void
     +	if (res)
     +		goto err_put_i2c_dev;
      
    - 	pr_debug("adapter [%s] registered as minor %d\n", adap->name, adap->nr);
    + 	pr_debug("i2c-dev: adapter [%s] registered as minor %d\n",
    + 		 adap->name, adap->nr);
      	return 0;
     +
     +err_put_i2c_dev:
---

Results of testing on various branches:

| Branch                    | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| stable/linux-5.10.y       |  Success    |  Success   |