[PATCH 0/1] char: Use list_del_init() in misc_deregister()

xion.wang at mediatek.com xion.wang at mediatek.com
Wed Sep 3 23:37:03 PDT 2025


From: Xion Wang <xion.wang at mediatek.com>

Hi all,

This patch updates the misc_deregister() function to use list_del_init()
instead of list_del() when removing the device from the list.
While list_del() poisons the list pointers to catch invalid usage,
it does not reset the list head. 
If misc_deregister() is called more than once on the same device, 
list_empty() will not return true and list_del() may be called again,
leading to undefined behavior.

By switching to list_del_init(), we ensure the list head is reinitialized,
making the code more robust against double deregistration and
allowing safe usage of list_empty() after deregistration.

Fixes: b329becfc78b1 ("char: add WARN_ON() in misc_deregister()")

Let me know if you have any questions or suggestions.

Thanks,
Xion Wang

Xion Wang (1):
  char: Use list_del_init() in misc_deregister() to reinitialize list
    pointer

 drivers/char/misc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

-- 
2.45.2




More information about the linux-arm-kernel mailing list