From 199eebbae45791af0f37184dd495f16a6cf5c34a Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sat, 11 Feb 2012 03:05:32 -0500
Subject: [PATCH] um: deadlock in line_write_interrupt()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Richard Weinberger <richard@nod.at>
---
 arch/um/drivers/line.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/um/drivers/line.c b/arch/um/drivers/line.c
index 4a3c853689a3..4ab0d9c0911c 100644
--- a/arch/um/drivers/line.c
+++ b/arch/um/drivers/line.c
@@ -344,6 +344,7 @@ static irqreturn_t line_write_interrupt(int irq, void *data)
 	spin_lock(&line->lock);
 	err = flush_buffer(line);
 	if (err == 0) {
+		spin_unlock(&line->lock);
 		return IRQ_NONE;
 	} else if (err < 0) {
 		line->head = line->buffer;
-- 
2.20.1