In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: hci_sync: Serialize local codec list cleanup

hci_dev_close_sync() clears hdev->local_codecs after releasing hdev->lock.
Codec list additions and both traversals in sco_sock_getsockopt() use that
lock, but the close path does not. A close and BT_CODEC query can therefore
interleave as follows:

hci_dev_close_sync() sco_sock_getsockopt()
hci_dev_lock()
fetch codec entry
hci_codec_list_clear()
kfree(entry)
read entry->id

The reader then accesses an entry which the close path has freed. KASAN

BUG: KASAN: slab-use-after-free in sco_sock_getsockopt+0xfa0/0xfe0
Read of size 1 at addr ffff8881001c3450
Call Trace:
sco_sock_getsockopt+0xfa0/0xfe0
do_sock_getsockopt+0x537/0x7b0
__sys_getsockopt+0xf2/0x170
Allocated by task 92:
hci_codec_list_add.isra.0+0x2c/0x440
hci_read_codec_capabilities+0x224/0x590
hci_read_supported_codecs+0x2c2/0x640
Freed by task 92:
kfree+0x131/0x3c0
hci_codec_list_clear+0xd8/0x160
hci_dev_close_sync+0x92a/0xfa0

Take hdev->lock around the clear operation at its existing point in the
close path. This makes the clear wait for active readers and prevents a new
traversal until the list is empty without changing teardown ordering.