hwmon/f71805f: Fix a race condition

Hi all,

I think I introduced a potential race condition bug with commit 51c997d80e1f625aea3426a8a9087f5830ac6db3. I didn't realize it back then, but platform_device_put and platform_device_release both appear to free the platform data associated with the device. This makes an explicit kfree redundant at best, and maybe even racy, as it might occur while someone still holds a reference to the platform device.

Can somebody with more experience with platform drivers than I have myself confirm that the current code is broken and that the fix below is correct?

Thanks.

---
 drivers/hwmon/f71805f.c |    8 +-------
 1 files changed, 1 insertion(+), 7 deletions(-)

@@ -1290,14 +1290,11 @@
 	if (err) {
 		printk(KERN_ERR DRVNAME ": Device addition failed (%d)\n",
 		       err);
-		goto exit_kfree_data;
+		goto exit_device_put;
 	}
 
 	return 0;
 
-exit_kfree_data:
-	kfree(pdev->dev.platform_data);
-	pdev->dev.platform_data = NULL;
 exit_device_put:
 	platform_device_put(pdev);
 exit:

@@ -1390,10 +1387,7 @@
 
 static void __exit f71805f_exit(void)
 {
-	kfree(pdev->dev.platform_data);
-	pdev->dev.platform_data = NULL;
 	platform_device_unregister(pdev);
-
 	platform_driver_unregister(&f71805f_driver);
 }
 

Jean Delvare