tty: Fix SIGTTOU not sent with tcflush()
authorPeter Hurley <peter@hurleysoftware.com>
Thu, 26 Sep 2013 00:13:04 +0000 (20:13 -0400)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 26 Sep 2013 00:52:17 +0000 (17:52 -0700)
Commit 'e7f3880cd9b98c5bf9391ae7acdec82b75403776'
  tty: Fix recursive deadlock in tty_perform_flush()
introduced a regression where tcflush() does not generate
SIGTTOU for background process groups.

Make sure ioctl(TCFLSH) calls tty_check_change() when
invoked from the line discipline.

Cc: stable@vger.kernel.org # v3.10+
Reported-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/tty/tty_ioctl.c

index 03ba081c577251a0947466b79f23b36b359b51c1..6fd60fece6b4b01684695b7df4af376e695ff873 100644 (file)
@@ -1201,6 +1201,9 @@ int n_tty_ioctl_helper(struct tty_struct *tty, struct file *file,
                }
                return 0;
        case TCFLSH:
+               retval = tty_check_change(tty);
+               if (retval)
+                       return retval;
                return __tty_perform_flush(tty, arg);
        default:
                /* Try the mode commands */