extcon: Fixed sysfs duplicate filename issue

With current extcon_dev_unregister() timing, ida_free is before
device_unregister(), that may cause current id re-alloc to another
device in extcon_dev_register() context but sysfs filename path not
removal completed yet.

The right timing shows below:
on extcon_dev_register: ida_alloc() -> device_register()
on extcon_dev_unregister: device_unregister() -> ida_free()

stack information when an error occurs:
sysfs: cannot create duplicate filename '/class/extcon/extcon1'
Call trace:
 sysfs_warn_dup+0x68/0x88
 sysfs_do_create_link_sd+0x94/0xdc
 sysfs_create_link+0x30/0x48
 device_add_class_symlinks+0xb4/0x12c
 device_add+0x1e0/0x48c
 device_register+0x20/0x34
 extcon_dev_register+0x3b8/0x5c4

Fixes: 7bba9e81a6fb ("extcon: Use unique number for the extcon device ID")
Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Michael Wu <michael@allwinnertech.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Link: https://lore.kernel.org/lkml/20251024024946.16618-1-michael@allwinnertech.com/

diff --git a/drivers/extcon/extcon.c b/drivers/extcon/extcon.c
index d9e9815a5f962690e40b05250ddcdeb9566d7890..98d85cc114a7f18da5dfdac9000d14dadb1a1aa3 100644 (file)
--- a/drivers/extcon/extcon.c
+++ b/drivers/extcon/extcon.c
@@ -1366,10 +1366,10 @@ void extcon_dev_unregister(struct extcon_dev *edev)
                return;
        }
 
-       ida_free(&extcon_dev_ids, edev->id);
-
        device_unregister(&edev->dev);
 
+       ida_free(&extcon_dev_ids, edev->id);
+
        if (edev->mutually_exclusive && edev->max_supported) {
                for (index = 0; edev->mutually_exclusive[index];
                                index++)