In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: RFCOMM: FIX possible deadlock in rfcommskstate_change
rfcommskstatechange attempts to use socklock so it must never be called with it locked but rfcommsockioctl always attempt to lock it causing the following trace:
====================================================== WARNING: possible circular locking dependency detected
syz-executor386/5093 is trying to acquire lock: ffff88807c396258 (sklock-AFBLUETOOTH-BTPROTORFCOMM){+.+.}-{0:0}, at: locksock include/net/sock.h:1671 [inline] ffff88807c396258 (sklock-AFBLUETOOTH-BTPROTORFCOMM){+.+.}-{0:0}, at: rfcommskstatechange+0x5b/0x310 net/bluetooth/rfcomm/sock.c:73
but task is already holding lock: ffff88807badfd28 (&d->lock){+.+.}-{3:3}, at: _rfcommdlc_close+0x226/0x6a0 net/bluetooth/rfcomm/core.c:491