linux-kernel - [PATCH 3.13.y-ckt 038/121] tty: Prevent "read/write wait queue active!" log flooding

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Message-Id: <1417548000-1794-39-git-send-email-kamal@canonical.com>
Date:	Tue,  2 Dec 2014 11:18:37 -0800
From:	Kamal Mostafa <kamal@...onical.com>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org,
	kernel-team@...ts.ubuntu.com
Cc:	Peter Hurley <peter@...leysoftware.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Kamal Mostafa <kamal@...onical.com>
Subject: [PATCH 3.13.y-ckt 038/121] tty: Prevent "read/write wait queue active!" log flooding

3.13.11-ckt12 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Peter Hurley <peter@...leysoftware.com>

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@...leysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@...onical.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 25d0741..da7d0a2 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);
-- 
1.9.1

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