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 (file)
--- 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;
 }