netdev - [PATCH 5/5] TTY: fix tty_wait_until

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1425461947-15888-6-git-send-email-johan@kernel.org>
Date:	Wed,  4 Mar 2015 10:39:07 +0100
From:	Johan Hovold <johan@...nel.org>
To:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:	Jiri Slaby <jslaby@...e.cz>, Samuel Ortiz <samuel@...tiz.org>,
	"David S. Miller" <davem@...emloft.net>,
	Peter Hurley <peter@...leysoftware.com>,
	Alan Cox <alan@...ux.intel.com>, linux-kernel@...r.kernel.org,
	linux-usb@...r.kernel.org, linux-serial@...r.kernel.org,
	netdev@...r.kernel.org,
	ZIV-Asier Llano Palacios <asier.llano@...lobal.com>,
	Johan Hovold <johan@...nel.org>
Subject: [PATCH 5/5] TTY: fix tty_wait_until_sent maximum timeout

Currently tty_wait_until_sent may take up to twice as long as the
requested timeout while waiting for driver and hardware buffers to
drain.

Fix this by taking the remaining number of jiffies after waiting for
driver buffers to drain into account so that the timeout actually
becomes a maximum timeout as it is documented to be.

Note that this specifically implies tighter timings when closing a port
as a consequence of actually honouring the port closing-wait setting
for drivers relying on tty_wait_until_sent_from_close (e.g. via
tty_port_close_start).

Signed-off-by: Johan Hovold <johan@...nel.org>
---
 drivers/tty/tty_ioctl.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/tty/tty_ioctl.c b/drivers/tty/tty_ioctl.c
index 89ae23ac9ae6..632fc8152061 100644
--- a/drivers/tty/tty_ioctl.c
+++ b/drivers/tty/tty_ioctl.c
@@ -218,10 +218,10 @@ void tty_wait_until_sent(struct tty_struct *tty, long timeout)
 	if (!timeout)
 		timeout = MAX_SCHEDULE_TIMEOUT;
 
-	if (wait_event_interruptible_timeout(tty->write_wait,
-			!tty_chars_in_buffer(tty), timeout) < 0) {
+	timeout = wait_event_interruptible_timeout(tty->write_wait,
+			!tty_chars_in_buffer(tty), timeout);
+	if (timeout <= 0)
 		return;
-	}
 
 	if (timeout == MAX_SCHEDULE_TIMEOUT)
 		timeout = 0;
-- 
2.0.5

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html