From: Tedd Ho-Jeong An <tedd.an@xxxxxxxxx>
If the user->list is deleted with list_del(), it doesn't initialize the
entry which can cause the issue with list_empty(). According to the
comment from the list.h, list_empty() returns false even if the list is
empty and put the entry in an undefined state.
/**
* list_del - deletes entry from list.
* @entry: the element to delete from the list.
* Note: list_empty() on entry does not return true after this, the entry is
* in an undefined state.
*/
Because of this behavior, list_empty() returns false even if list is empty
when the device is reconnected.
So, user->list needs to be re-initialized after list_del(). list.h already
have a macro list_del_init() which deletes the entry and initailze it again.
Signed-off-by: Tedd Ho-Jeong An <tedd.an@xxxxxxxxx>
Tested-by: Jörg Otte <jrg.otte@xxxxxxxxx>
Signed-off-by: Marcel Holtmann <marcel@xxxxxxxxxxxx>
---
net/bluetooth/l2cap_core.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index 1700c3dc3fe1..eb0125d1451d 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -1649,7 +1649,7 @@ void l2cap_unregister_user(struct l2cap_conn *conn, struct l2cap_user *user)
if (list_empty(&user->list))
goto out_unlock;
- list_del(&user->list);
+ list_del_init(&user->list);
user->remove(conn, user);
out_unlock:
@@ -1663,7 +1663,7 @@ static void l2cap_unregister_all_users(struct l2cap_conn *conn)
while (!list_empty(&conn->users)) {
user = list_first_entry(&conn->users, struct l2cap_user, list);
- list_del(&user->list);
+ list_del_init(&user->list);
user->remove(conn, user);
}
}
--
2.17.1
