[3.16.y-ckt stable] Patch "tty: Prevent "read/write wait queue active!" log flooding" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    tty: Prevent "read/write wait queue active!" log flooding

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt2.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 2004c0559016a6e79928c1f6709b5a554e753c09 Mon Sep 17 00:00:00 2001
From: Peter Hurley <peter at hurleysoftware.com>
Date: Thu, 16 Oct 2014 13:54:36 -0400
Subject: tty: Prevent "read/write wait queue active!" log flooding

commit 494c1eac7e73f719af9d474a96ec8494c33efd6a upstream.

Only print one warning when a task is on the read_wait or write_wait
wait queue at final tty release.

Signed-off-by: Peter Hurley <peter at hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/tty/tty_io.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index fd682252bbac..fd4095cd4bd6 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -1702,6 +1702,7 @@ int tty_release(struct inode *inode, struct file *filp)
 	int	idx;
 	char	buf[64];
 	long	timeout = 0;
+	int	once = 1;

 	if (tty_paranoia_check(tty, inode, __func__))
 		return 0;
@@ -1782,8 +1783,11 @@ int tty_release(struct inode *inode, struct file *filp)
 		if (!do_sleep)
 			break;

-		printk(KERN_WARNING "%s: %s: read/write wait queue active!\n",
-				__func__, tty_name(tty, buf));
+		if (once) {
+			once = 0;
+			printk(KERN_WARNING "%s: %s: read/write wait queue active!\n",
+			       __func__, tty_name(tty, buf));
+		}
 		tty_unlock_pair(tty, o_tty);
 		mutex_unlock(&tty_mutex);
 		schedule_timeout_killable(timeout);
--
2.1.0