Hi, On Fri, Apr 28, 2023 at 3:27 AM Li Tuo <islituo@xxxxxxxxx> wrote: > > Hello, > > Our static analysis tool finds a possible data race in the l2cap protocol > in Linux 6.3.0-rc7: > > In most calling contexts, the variable sk->sk_socket is accessed > with holding the lock sk->sk_callback_lock. Here is an example: > > l2cap_sock_accept() --> Line 346 in net/bluetooth/l2cap_sock.c > bt_accept_dequeue() --> Line 368 in net/bluetooth/l2cap_sock.c > sock_graft() --> Line 240 in net/bluetooth/af_bluetooth.c > write_lock_bh(&sk->sk_callback_lock); --> Line 2081 in include/net/sock.h (Lock sk->sk_callback_lock) > sk_set_socket() --> Line 2084 in include/net/sock.h > sk->sk_socket = sock; --> Line 2054 in include/net/sock.h (Access sk->sk_socket) > > However, in the following calling context: > > sco_sock_shutdown() --> Line 1227 in net/bluetooth/sco.c > __sco_sock_close() --> Line 1243 in net/bluetooth/sco.c > BT_DBG(..., sk->sk_socket); --> Line 431 in net/bluetooth/sco.c (Access sk->sk_socket) > > the variable sk->sk_socket is accessed without holding the lock > sk->sk_callback_lock, and thus a data race may occur. > > Reported-by: BassCheck <bass@xxxxxxxxxxx> Need to check in detail what it means to hold the sk_callback_lock, btw is this static analysis tool of yours something public that we can use in our CI to detect these problems? -- Luiz Augusto von Dentz
