Patch "staging: pi433: fix memory leak with using debugfs_lookup()" has been added to the 6.1-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    staging: pi433: fix memory leak with using debugfs_lookup()

to the 6.1-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     staging-pi433-fix-memory-leak-with-using-debugfs_loo.patch
and it can be found in the queue-6.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 17b46b300ed1d560660a42055bf0232fe5936a31
Author: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Date:   Thu Feb 2 15:11:38 2023 +0100

    staging: pi433: fix memory leak with using debugfs_lookup()
    
    [ Upstream commit 2f36e789e540df6a9fbf471b3a2ba62a8b361586 ]
    
    When calling debugfs_lookup() the result must have dput() called on it,
    otherwise the memory will leak over time.  To make things simpler, just
    call debugfs_lookup_and_remove() instead which handles all of the logic
    at once.  This requires saving off the root directory dentry to make
    creation of individual device subdirectories easier.
    
    Cc: Paulo Miguel Almeida <paulo.miguel.almeida.rodenas@xxxxxxxxx>
    Cc: Dan Carpenter <error27@xxxxxxxxx>
    Cc: Sidong Yang <realwakka@xxxxxxxxx>
    Cc: Liu Shixin <liushixin2@xxxxxxxxxx>
    Cc: "Uwe Kleine-König" <u.kleine-koenig@xxxxxxxxxxxxxx>
    Link: https://lore.kernel.org/r/20230202141138.2291946-1-gregkh@xxxxxxxxxxxxxxxxxxx
    Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/staging/pi433/pi433_if.c b/drivers/staging/pi433/pi433_if.c
index d4e06a3929f3d..b59f6a4cb611a 100644
--- a/drivers/staging/pi433/pi433_if.c
+++ b/drivers/staging/pi433/pi433_if.c
@@ -55,6 +55,7 @@
 static dev_t pi433_dev;
 static DEFINE_IDR(pi433_idr);
 static DEFINE_MUTEX(minor_lock); /* Protect idr accesses */
+static struct dentry *root_dir;	/* debugfs root directory for the driver */
 
 static struct class *pi433_class; /* mainly for udev to create /dev/pi433 */
 
@@ -1306,8 +1307,7 @@ static int pi433_probe(struct spi_device *spi)
 	/* spi setup */
 	spi_set_drvdata(spi, device);
 
-	entry = debugfs_create_dir(dev_name(device->dev),
-				   debugfs_lookup(KBUILD_MODNAME, NULL));
+	entry = debugfs_create_dir(dev_name(device->dev), root_dir);
 	debugfs_create_file("regs", 0400, entry, device, &pi433_debugfs_regs_fops);
 
 	return 0;
@@ -1333,9 +1333,8 @@ static int pi433_probe(struct spi_device *spi)
 static void pi433_remove(struct spi_device *spi)
 {
 	struct pi433_device	*device = spi_get_drvdata(spi);
-	struct dentry *mod_entry = debugfs_lookup(KBUILD_MODNAME, NULL);
 
-	debugfs_remove(debugfs_lookup(dev_name(device->dev), mod_entry));
+	debugfs_lookup_and_remove(dev_name(device->dev), root_dir);
 
 	/* free GPIOs */
 	free_gpio(device);
@@ -1408,7 +1407,7 @@ static int __init pi433_init(void)
 		return PTR_ERR(pi433_class);
 	}
 
-	debugfs_create_dir(KBUILD_MODNAME, NULL);
+	root_dir = debugfs_create_dir(KBUILD_MODNAME, NULL);
 
 	status = spi_register_driver(&pi433_spi_driver);
 	if (status < 0) {
@@ -1427,7 +1426,7 @@ static void __exit pi433_exit(void)
 	spi_unregister_driver(&pi433_spi_driver);
 	class_destroy(pi433_class);
 	unregister_chrdev(MAJOR(pi433_dev), pi433_spi_driver.driver.name);
-	debugfs_remove_recursive(debugfs_lookup(KBUILD_MODNAME, NULL));
+	debugfs_remove(root_dir);
 }
 module_exit(pi433_exit);