From 03315b59165ee2049a4b903a1b0b8bf673d701fa Mon Sep 17 00:00:00 2001
From: Alexander Beregalov <a.beregalov@gmail.com>
Date: Fri, 5 Mar 2010 13:42:33 -0800
Subject: uml: line.c: avoid NULL pointer dereference

Assign tty only if line is not NULL.

[akpm@linux-foundation.org: simplification]
Signed-off-by: Alexander Beregalov <a.beregalov@gmail.com>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/um/drivers/line.c b/arch/um/drivers/line.c
index cf8a97f..64cda95 100644
--- a/arch/um/drivers/line.c
+++ b/arch/um/drivers/line.c
@@ -18,10 +18,10 @@ static irqreturn_t line_interrupt(int irq, void *data)
 {
 	struct chan *chan = data;
 	struct line *line = chan->line;
-	struct tty_struct *tty = line->tty;
+	struct tty_struct *tty;
 
 	if (line)
-		chan_interrupt(&line->chan_list, &line->task, tty, irq);
+		chan_interrupt(&line->chan_list, &line->task, line->tty, irq);
 	return IRQ_HANDLED;
 }
 
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