linux-kernel - [PATCH] eeprom: idt_89hpesx: Fix error handling in idt

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Date:   Thu, 10 Nov 2022 02:00:30 +0000
From:   Yuan Can <yuancan@...wei.com>
To:     <arnd@...db.de>, <gregkh@...uxfoundation.org>,
        <wsa+renesas@...g-engineering.com>, <benjamin.mugnier@...s.st.com>,
        <dmitry.torokhov@...il.com>, <cmo@...exis.com>,
        <u.kleine-koenig@...gutronix.de>, <error27@...il.com>,
        <justinstitt@...gle.com>, <fancer.lancer@...il.com>,
        <linux-kernel@...r.kernel.org>
CC:     <yuancan@...wei.com>
Subject: [PATCH] eeprom: idt_89hpesx: Fix error handling in idt_init()

A problem about idt_89hpesx create debugfs failed is triggered with the
following log given:

 [ 4973.269647] debugfs: Directory 'idt_csr' with parent '/' already present!

The reason is that idt_init() returns i2c_add_driver() directly without
checking its return value, if i2c_add_driver() failed, it returns without
destroy the newly created debugfs, resulting the debugfs of idt_csr can
never be created later.

 idt_init()
   debugfs_create_dir() # create debugfs directory
   i2c_add_driver()
     driver_register()
       bus_add_driver()
         priv = kzalloc(...) # OOM happened
   # return without destroy debugfs directory

Fix by removing debugfs when i2c_add_driver() returns error.

Fixes: cfad6425382e ("eeprom: Add IDT 89HPESx EEPROM/CSR driver")
Signed-off-by: Yuan Can <yuancan@...wei.com>
---
 drivers/misc/eeprom/idt_89hpesx.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/misc/eeprom/idt_89hpesx.c b/drivers/misc/eeprom/idt_89hpesx.c
index bb3ed352b95f..367054e0ced4 100644
--- a/drivers/misc/eeprom/idt_89hpesx.c
+++ b/drivers/misc/eeprom/idt_89hpesx.c
@@ -1566,12 +1566,20 @@ static struct i2c_driver idt_driver = {
  */
 static int __init idt_init(void)
 {
+	int ret;
+
 	/* Create Debugfs directory first */
 	if (debugfs_initialized())
 		csr_dbgdir = debugfs_create_dir("idt_csr", NULL);
 
 	/* Add new i2c-device driver */
-	return i2c_add_driver(&idt_driver);
+	ret = i2c_add_driver(&idt_driver);
+	if (ret) {
+		debugfs_remove_recursive(csr_dbgdir);
+		return ret;
+	}
+
+	return 0;
 }
 module_init(idt_init);
 
-- 
2.17.1