tty: Fix transient pty write() EIO
Commit 699390354da6c258b65bf8fa79cfd5feaede50b6
('pty: Ignore slave pty close() if never successfully opened')
introduced a bug with ptys whereby a write() in parallel with an
open() on an existing pty could mistakenly indicate an I/O error.
Only indicate an I/O error if the condition on open() actually exists.
Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Tested-by: Mikael Pettersson <mikpe@it.uu.se>
Cc: stable <stable@vger.kernel.org> # 3.9
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c
index 59bfaec..abfd990 100644
--- a/drivers/tty/pty.c
+++ b/drivers/tty/pty.c
@@ -244,14 +244,9 @@
static int pty_open(struct tty_struct *tty, struct file *filp)
{
- int retval = -ENODEV;
-
if (!tty || !tty->link)
- goto out;
+ return -ENODEV;
- set_bit(TTY_IO_ERROR, &tty->flags);
-
- retval = -EIO;
if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
goto out;
if (test_bit(TTY_PTY_LOCK, &tty->link->flags))
@@ -262,9 +257,11 @@
clear_bit(TTY_IO_ERROR, &tty->flags);
clear_bit(TTY_OTHER_CLOSED, &tty->link->flags);
set_bit(TTY_THROTTLED, &tty->flags);
- retval = 0;
+ return 0;
+
out:
- return retval;
+ set_bit(TTY_IO_ERROR, &tty->flags);
+ return -EIO;
}
static void pty_set_termios(struct tty_struct *tty,