commit 093facf3634da1b0c2cc7ed106f1983da901bbab
author Vladimir Davydov <vdavydov@parallels.com> Tue Jul 15 12:25:28 2014 +0400
committer Marcel Holtmann <marcel@holtmann.org> Thu Jul 17 12:13:06 2014 +0200
tree 572c591aef2ac03e8278023cac4c801bc25bbed9
parent 02f3e25457915728624b976b0382601b5605ad64

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 <vdavydov@parallels.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Cc: stable@vger.kernel.org

net/bluetooth/sco.c

diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c
index ebf7ee6..7ee9e4a 100644
--- a/net/bluetooth/sco.c
+++ b/net/bluetooth/sco.c
@@ -970,7 +970,8 @@
 		sco_sock_clear_timer(sk);
 		__sco_sock_close(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);
 	}
@@ -990,7 +991,8 @@
 
 	sco_sock_close(sk);
 
-	if (sock_flag(sk, SOCK_LINGER) && sk->sk_lingertime) {
+	if (sock_flag(sk, SOCK_LINGER) && sk->sk_lingertime &&
+	    !(current->flags & PF_EXITING)) {
 		lock_sock(sk);
 		err = bt_sock_wait_state(sk, BT_CLOSED, sk->sk_lingertime);
 		release_sock(sk);