* PROBLEM: n_hdlc not atomic use tty->flags.
@ 2011-11-07 7:32 Ilya Zykov
2011-11-07 10:24 ` Alan Cox
0 siblings, 1 reply; 2+ messages in thread
From: Ilya Zykov @ 2011-11-07 7:32 UTC (permalink / raw)
To: Paul Fulghum; +Cc: Greg Kroah-Hartman, linux-kernel, Alan Cox, Ilya Zykov
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>
---
diff -uprN -X ../../dontdiff a/drivers/tty/n_hdlc.c b/drivers/tty/n_hdlc.c
--- a/drivers/tty/n_hdlc.c 2011-05-19 08:06:34.000000000 +0400
+++ b/drivers/tty/n_hdlc.c 2011-11-06 16:30:13.000000000 +0400
@@ -417,7 +417,7 @@ static void n_hdlc_send_frames(struct n_
__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 @@ static void n_hdlc_send_frames(struct n_
}
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 @@ static void n_hdlc_tty_wakeup(struct tty
return;
if (tty != n_hdlc->tty) {
- tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);
+ clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
return;
}
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: PROBLEM: n_hdlc not atomic use tty->flags.
2011-11-07 7:32 PROBLEM: n_hdlc not atomic use tty->flags Ilya Zykov
@ 2011-11-07 10:24 ` Alan Cox
0 siblings, 0 replies; 2+ messages in thread
From: Alan Cox @ 2011-11-07 10:24 UTC (permalink / raw)
To: Ilya Zykov; +Cc: Paul Fulghum, Greg Kroah-Hartman, linux-kernel, Alan Cox
On Mon, 07 Nov 2011 11:32:46 +0400
Ilya Zykov <ilya@ilyx.ru> wrote:
> N_HDLC can spoil tty->flags because use not atomic operations on tty->flags.
> I use n_hdlc line discipline and it happens.
Acked-by: Alan Cox <alan@linux.intel.com>
^ permalink raw reply [flat|nested] 2+ messages in thread
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2011-11-07 7:32 PROBLEM: n_hdlc not atomic use tty->flags Ilya Zykov
2011-11-07 10:24 ` Alan Cox
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