misc: remove ineffective WARN_ON() check from misc_deregister()

The WARN_ON(list_empty(&misc->list)) in misc_deregister() does
not catch any practical error conditions:
- For statically allocated miscdevice structures, the list pointers
 are zero-initialized, so list_empty() returns false, not true.
- After list_del(), the pointers are set to LIST_POISON1 and LIST_POISON2,
 so repeated deregistration also fails to trigger the check.

Signed-off-by: Xion Wang <xion.wang@mediatek.com>
Link: https://lore.kernel.org/r/20250827024201.21407-2-xion.wang@mediatek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/char/misc.c b/drivers/char/misc.c
index a0aae0fc792666a7bdc0ba00da9dc02ff9cead42..69e8ce02e099f27602dfb36771eb0f7f97b8a924 100644 (file)
--- a/drivers/char/misc.c
+++ b/drivers/char/misc.c
@@ -283,9 +283,6 @@ EXPORT_SYMBOL(misc_register);
 
 void misc_deregister(struct miscdevice *misc)
 {
-       if (WARN_ON(list_empty(&misc->list)))
-               return;
-
        mutex_lock(&misc_mtx);
        list_del(&misc->list);
        device_destroy(&misc_class, MKDEV(MISC_MAJOR, misc->minor));