linux-kernel - [PATCH 5.15 187/262] auxdisplay: lcd2s: Use proper API to free the instance of charlcd object

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Message-Id: <20220307091707.746320066@linuxfoundation.org>
Date:   Mon,  7 Mar 2022 10:18:51 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Lars Poeschel <poeschel@...onage.de>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Miguel Ojeda <ojeda@...nel.org>
Subject: [PATCH 5.15 187/262] auxdisplay: lcd2s: Use proper API to free the instance of charlcd object

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

commit 9ed331f8a0fb674f4f06edf05a1687bf755af27b upstream.

While it might work, the current approach is fragile in a few ways:
- whenever members in the structure are shuffled, the pointer will be wrong
- the resource freeing may include more than covered by kfree()

Fix this by using charlcd_free() call instead of kfree().

Fixes: 8c9108d014c5 ("auxdisplay: add a driver for lcd2s character display")
Cc: Lars Poeschel <poeschel@...onage.de>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Signed-off-by: Miguel Ojeda <ojeda@...nel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/auxdisplay/lcd2s.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/auxdisplay/lcd2s.c
+++ b/drivers/auxdisplay/lcd2s.c
@@ -336,7 +336,7 @@ static int lcd2s_i2c_probe(struct i2c_cl
 	return 0;
 
 fail1:
-	kfree(lcd);
+	charlcd_free(lcd2s->charlcd);
 	return err;
 }
 
@@ -345,7 +345,7 @@ static int lcd2s_i2c_remove(struct i2c_c
 	struct lcd2s_data *lcd2s = i2c_get_clientdata(i2c);
 
 	charlcd_unregister(lcd2s->charlcd);
-	kfree(lcd2s->charlcd);
+	charlcd_free(lcd2s->charlcd);
 	return 0;
 }