tty: n_hdlc not atomic use tty->flags.
N_HDLC can spoil tty->flags because use not atomic operations on tty->flags.
I use n_hdlc line discipline and it happens.
Signed-off-by: Ilya Zykov <ilya@ilyx.ru>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/tty/n_hdlc.c b/drivers/tty/n_hdlc.c
index cea5603..a09ce3e 100644
--- a/drivers/tty/n_hdlc.c
+++ b/drivers/tty/n_hdlc.c
@@ -417,7 +417,7 @@
__FILE__,__LINE__,tbuf,tbuf->count);
/* Send the next block of data to device */
- tty->flags |= (1 << TTY_DO_WRITE_WAKEUP);
+ set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
actual = tty->ops->write(tty, tbuf->buf, tbuf->count);
/* rollback was possible and has been done */
@@ -459,7 +459,7 @@
}
if (!tbuf)
- tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);
+ clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
/* Clear the re-entry flag */
spin_lock_irqsave(&n_hdlc->tx_buf_list.spinlock, flags);
@@ -491,7 +491,7 @@
return;
if (tty != n_hdlc->tty) {
- tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);
+ clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
return;
}