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

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

Cc: <stable@vger.kernel.org> # 3.4.x+
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 4021c10..0508a1d 100644 (file)
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -1710,6 +1710,7 @@ 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;
@@ -1790,8 +1791,11 @@ 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);