Re: [PATCH] bluetooth: never linger on process exit

If the current process is exiting, lingering on socket close will make
it unkillable, so we should avoid it.

Reproducer:

 #include <sys/types.h>
 #include <sys/socket.h>

 #define BTPROTO_L2CAP   0
 #define BTPROTO_SCO     2
 #define BTPROTO_RFCOMM  3

 int main()
 {
         int fd;
         struct linger ling;

         fd = socket(PF_BLUETOOTH, SOCK_STREAM, BTPROTO_RFCOMM);
         //or: fd = socket(PF_BLUETOOTH, SOCK_DGRAM, BTPROTO_L2CAP);
         //or: fd = socket(PF_BLUETOOTH, SOCK_SEQPACKET, BTPROTO_SCO);

         ling.l_onoff = 1;
         ling.l_linger = 1000000000;
         setsockopt(fd, SOL_SOCKET, SO_LINGER, &ling, sizeof(ling));

         return 0;
 }

Signed-off-by: Vladimir Davydov <redacted>
Cc: Marcel Holtmann <marcel@holtmann.org>
Cc: Gustavo Padovan <redacted>
Cc: Johan Hedberg <redacted>
---
net/bluetooth/l2cap_sock.c  |    3 ++-
net/bluetooth/rfcomm/sock.c |    3 ++-
net/bluetooth/sco.c         |    6 ++++--
3 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c
index e1378693cc90..d0fd8b04f2e6 100644
--- a/net/bluetooth/l2cap_sock.c
+++ b/net/bluetooth/l2cap_sock.c

@@ -1111,7 +1111,8 @@ static int l2cap_sock_shutdown(struct socket *sock, int how)

		l2cap_chan_close(chan, 0);
		lock_sock(sk);

-		if (sock_flag(sk, SOCK_LINGER) && sk->sk_lingertime)
+		if (sock_flag(sk, SOCK_LINGER) && sk->sk_lingertime &&
+		    !(current->flags & PF_EXITING))
			err = bt_sock_wait_state(sk, BT_CLOSED,
						 sk->sk_lingertime);
	}