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@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[lizf: Backported to 3.4: adjust context]
Signed-off-by: Zefan Li <lizefan@huawei.com>

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 2d66bee..a07eb4c 100644 (file)
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -1634,6 +1634,7 @@ 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;
@@ -1714,8 +1715,11 @@ int tty_release(struct inode *inode, struct file *filp)
                if (!do_sleep)
                        break;
 
-               printk(KERN_WARNING "%s: %s: read/write wait queue active!\n",
+               if (once) {
+                       once = 0;
+                       printk(KERN_WARNING "%s: %s: read/write wait queue active!\n",
                                __func__, tty_name(tty, buf));
+               }
                tty_unlock();
                mutex_unlock(&tty_mutex);
                schedule_timeout_killable(timeout);