From: Ilya Zykov <ilya@ilyx.ru>
To: Paul Fulghum <paulkf@microgate.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>,
linux-kernel@vger.kernel.org, Alan Cox <alan@linux.intel.com>,
Ilya Zykov <ilya@ilyx.ru>
Subject: PROBLEM: n_hdlc not atomic use tty->flags.
Date: Mon, 07 Nov 2011 11:32:46 +0400 [thread overview]
Message-ID: <4EB7899E.5090006@ilyx.ru> (raw)
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;
}
next reply other threads:[~2011-11-07 7:32 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-07 7:32 Ilya Zykov [this message]
2011-11-07 10:24 ` PROBLEM: n_hdlc not atomic use tty->flags Alan Cox
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4EB7899E.5090006@ilyx.ru \
--to=ilya@ilyx.ru \
--cc=alan@linux.intel.com \
--cc=gregkh@suse.de \
--cc=linux-kernel@vger.kernel.org \
--cc=paulkf@microgate.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox