linux-kernel - [PATCH 3/3] Bluetooth: Remove debugfs directory on module init failure

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Message-Id: <20241004003030.160721-4-dev@aaront.org>
Date: Fri,  4 Oct 2024 00:30:30 +0000
From: Aaron Thompson <dev@...ont.org>
To: Johan Hedberg <johan.hedberg@...il.com>,
	Luiz Augusto von Dentz <luiz.dentz@...il.com>,
	Marcel Holtmann <marcel@...tmann.org>,
	linux-bluetooth@...r.kernel.org,
	linux-kernel@...r.kernel.org
Cc: Aaron Thompson <dev@...ont.org>,
	stable@...r.kernel.org
Subject: [PATCH 3/3] Bluetooth: Remove debugfs directory on module init failure

From: Aaron Thompson <dev@...ont.org>

If bt_init() fails, the debugfs directory currently is not removed. If
the module is loaded again after that, the debugfs directory is not set
up properly due to the existing directory.

  # modprobe bluetooth
  # ls -laF /sys/kernel/debug/bluetooth
  total 0
  drwxr-xr-x  2 root root 0 Sep 27 14:26 ./
  drwx------ 31 root root 0 Sep 27 14:25 ../
  -r--r--r--  1 root root 0 Sep 27 14:26 l2cap
  -r--r--r--  1 root root 0 Sep 27 14:26 sco
  # modprobe -r bluetooth
  # ls -laF /sys/kernel/debug/bluetooth
  ls: cannot access '/sys/kernel/debug/bluetooth': No such file or directory
  #

  # modprobe bluetooth
  modprobe: ERROR: could not insert 'bluetooth': Invalid argument
  # dmesg | tail -n 6
  Bluetooth: Core ver 2.22
  NET: Registered PF_BLUETOOTH protocol family
  Bluetooth: HCI device and connection manager initialized
  Bluetooth: HCI socket layer initialized
  Bluetooth: Faking l2cap_init() failure for testing
  NET: Unregistered PF_BLUETOOTH protocol family
  # ls -laF /sys/kernel/debug/bluetooth
  total 0
  drwxr-xr-x  2 root root 0 Sep 27 14:31 ./
  drwx------ 31 root root 0 Sep 27 14:26 ../
  #

  # modprobe bluetooth
  # dmesg | tail -n 7
  Bluetooth: Core ver 2.22
  debugfs: Directory 'bluetooth' with parent '/' already present!
  NET: Registered PF_BLUETOOTH protocol family
  Bluetooth: HCI device and connection manager initialized
  Bluetooth: HCI socket layer initialized
  Bluetooth: L2CAP socket layer initialized
  Bluetooth: SCO socket layer initialized
  # ls -laF /sys/kernel/debug/bluetooth
  total 0
  drwxr-xr-x  2 root root 0 Sep 27 14:31 ./
  drwx------ 31 root root 0 Sep 27 14:26 ../
  #

Cc: stable@...r.kernel.org
Fixes: ffcecac6a738 ("Bluetooth: Create root debugfs directory during module init")
Signed-off-by: Aaron Thompson <dev@...ont.org>
---
 net/bluetooth/af_bluetooth.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/bluetooth/af_bluetooth.c b/net/bluetooth/af_bluetooth.c
index 67604ccec2f4..0d4b171b939a 100644
--- a/net/bluetooth/af_bluetooth.c
+++ b/net/bluetooth/af_bluetooth.c
@@ -825,6 +825,7 @@ static int __init bt_init(void)
 	bt_sysfs_cleanup();
 cleanup_led:
 	bt_leds_cleanup();
+	debugfs_remove_recursive(bt_debugfs);
 	return err;
 }
 
-- 
2.39.5