From: Luiz Augusto von Dentz luiz.von.dentz@intel.com
[ Upstream commit 812e92b824c1db16c9519f8624d48a9901a0d38f ]
Due to change to switch to use lock_sock inside rfcomm_sk_state_change the socket shutdown/release procedure can cause a deadlock:
rfcomm_sock_shutdown(): lock_sock(); __rfcomm_sock_close(): rfcomm_dlc_close(): __rfcomm_dlc_close(): rfcomm_dlc_lock(); rfcomm_sk_state_change(): lock_sock();
To fix this when the call __rfcomm_sock_close is now done without holding the lock_sock since rfcomm_dlc_lock exists to protect the dlc data there is no need to use lock_sock in that code path.
Link: https://lore.kernel.org/all/CAD+dNTsbuU4w+Y_P7o+VEN7BYCAbZuwZx2+tH+OTzCdcZF8... Fixes: b7ce436a5d79 ("Bluetooth: switch to lock_sock in RFCOMM") Signed-off-by: Luiz Augusto von Dentz luiz.von.dentz@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- net/bluetooth/rfcomm/sock.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/net/bluetooth/rfcomm/sock.c b/net/bluetooth/rfcomm/sock.c index 4bf4ea6cbb5e..21e24da4847f 100644 --- a/net/bluetooth/rfcomm/sock.c +++ b/net/bluetooth/rfcomm/sock.c @@ -902,7 +902,10 @@ static int rfcomm_sock_shutdown(struct socket *sock, int how) lock_sock(sk); if (!sk->sk_shutdown) { sk->sk_shutdown = SHUTDOWN_MASK; + + release_sock(sk); __rfcomm_sock_close(sk); + lock_sock(sk);
if (sock_flag(sk, SOCK_LINGER) && sk->sk_lingertime && !(current->flags & PF_EXITING))