From: Stanislav Kozina <skozina@redhat.com>
Date: Thu, 16 Aug 2012 11:01:47 +0000 (+0100)
Subject: Remove BUG_ON from n_tty_read()
X-Git-Tag: v3.5.6~39
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7e67dd66193c2325cbd2739522db3334413c3aea;p=thirdparty%2Fkernel%2Fstable.git

Remove BUG_ON from n_tty_read()

commit e9490e93c1978b6669f3e993caa3189be13ce459 upstream.

Change the BUG_ON to WARN_ON and return in case of tty->read_buf==NULL. We want to track a
couple of long standing reports of this but at the same time we can avoid killing the box.

Signed-off-by: Stanislav Kozina <skozina@redhat.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index ee1c268f5f9d6..26f0d0e4484bb 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -1728,7 +1728,8 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
 
 do_it_again:
 
-	BUG_ON(!tty->read_buf);
+	if (WARN_ON(!tty->read_buf))
+		return -EAGAIN;
 
 	c = job_control(tty, file);
 	if (c < 0)